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BACKGROUND: Puerarin is an isoflavone compound isolated from the roots of a leguminous plant, the wild kudzu. Various functional activities of this compound in multiple diseases have been reported. However, the effect and mechanism of puerarin in improving blood pressure remain non-elucidated. PURPOSE: The current study was designed to assess the preventive effects of puerarin on the onset and progression of hypertension and to verify the hypothesis that puerarin alleviates blood pressure by inhibiting the ROS/TLR4/NLRP3 inflammasome signaling pathway in the hypothalamic paraventricular nucleus (PVN) of salt-induced prehypertensive rats. METHODS: Male Dahl salt-sensitive rats were fed low NaCl salt (3% in drinking water) for the control (NS) group or 8% (HS) to induce prehypertension. Each batch was divided into two group and treated by bilateral PVN microinjection with either artificial cerebrospinal fluid or puerarin through a micro-osmotic pump for 6 weeks. The mean arterial pressure (MAP) was recorded, and samples were collected and analyzed. RESULTS: We concluded that puerarin significantly prevented the elevation of blood pressure and effectively alleviated the increase in heart rate caused by high salt. Norepinephrine (NE) in the plasma of salt-induced prehypertensive rats also decreased upon puerarin chronic infusion. Additionally, analysis of the PVN sample revealed that puerarin pretreatment decreased the positive cells and gene level of TLR4 (Toll-like receptor 4), NLRP3, Caspase-1 p10, NOX2, MyD88, NOX4, and proinflammatory cytokines in the PVN. Puerarin pretreatment also decreased NF-κBp65 activity, inhibited oxidative stress, and alleviated inflammatory responses in the PVN. CONCLUSION: We conclude that puerarin alleviated blood pressure via inhibition of the ROS/TLR4/NLRP3 inflammasome signaling pathway in the PVN, suggesting the therapeutic potential of puerarin in the prevention of hypertension.
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Presión Sanguínea , Inflamasomas , Isoflavonas , Proteína con Dominio Pirina 3 de la Familia NLR , Núcleo Hipotalámico Paraventricular , Especies Reactivas de Oxígeno , Transducción de Señal , Receptor Toll-Like 4 , Animales , Masculino , Ratas , Presión Sanguínea/efectos de los fármacos , Modelos Animales de Enfermedad , Hipertensión/inducido químicamente , Hipertensión/tratamiento farmacológico , Inflamasomas/metabolismo , Inflamasomas/efectos de los fármacos , Isoflavonas/farmacología , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Prehipertensión/tratamiento farmacológico , Ratas Endogámicas Dahl , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos , Cloruro de Sodio Dietético , Receptor Toll-Like 4/metabolismoRESUMEN
Hypertension is usually accompanied by elevated sympathetic tonicity, but how sympathetic hyperactivity is triggered is not clear. Recent advances revealed that microglia-centered neuroinflammation contributes to sympathetic excitation in hypertension. In this study, we performed a temporospatial analysis of microglia at both morphological and transcriptomic levels and found that microglia in the hypothalamic paraventricular nucleus (PVN), a sympathetic center, were early responders to hypertensive challenges. Vasculature analyses revealed that the PVN was characterized by high capillary density, thin vessel diameter, and complex vascular topology relative to other brain regions. As such, the PVN was susceptible to the penetration of ATP released from the vasculature in response to hemodynamic disturbance after blood pressure increase. Mechanistically, ATP ligation to microglial P2Y12 receptor was responsible for microglial inflammatory activation and the eventual sympathetic overflow. Together, these findings identified a distinct vasculature pattern rendering vulnerability of PVN pre-sympathetic neurons to hypertension-associated microglia-mediated inflammatory insults.
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Hemodinámica , Hipertensión , Microglía , Núcleo Hipotalámico Paraventricular , Sistema Nervioso Simpático , Núcleo Hipotalámico Paraventricular/metabolismo , Animales , Microglía/metabolismo , Hipertensión/fisiopatología , Ratones , Sistema Nervioso Simpático/fisiopatología , Masculino , Ratones Endogámicos C57BL , Adenosina Trifosfato/metabolismo , Receptores Purinérgicos P2Y12/metabolismo , Inflamación/inmunología , Presión Sanguínea , Neuronas/metabolismoRESUMEN
Hypertension is a globally prevalent disease, but the pathogenesis remains largely unclear. AMP-activated protein kinase (AMPK) is a nutrition-sensitive signal of cellular energy metabolism, which has a certain influence on the development of hypertension. Previously, we found a down-regulation of the phosphorylated (p-) form of AMPK, and the up-regulation of the angiotensin II type 1 receptor (AT1-R) and that of p-ERK1/2 in the hypothalamic paraventricular nucleus (PVN) of hypertensive rats. However, the exact mechanism underlying the relationship between AMPK and AT1-R in the PVN during hypertension remains unclear. Thus, we hypothesized that AMPK modulates AT1-R through the ERK1/2-NF-κB pathway in the PVN, thereby inhibiting sympathetic nerve activity and improving hypertension. To examine this hypothesis, we employed a renovascular hypertensive animal model developed via two-kidney, one-clip (2K1C) and sham-operated (SHAM). Artificial cerebrospinal fluid (aCSF), used as vehicle, or 5-amino-1-ß-D-ribofuranosyl-imidazole-4-carboxamide (AICAR, an AMPK activator, 60 µg/day) was microinjected bilaterally in the PVN of these rats for 4 weeks. In 2K1C rats, there an increase in systolic blood pressure (SBP) and circulating norepinephrine (NE). Also, the hypertensive rats had lowered expression of p-AMPK and p-AMPK/AMPK, elevated expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R, increased NF-κB p65 activity in the PVN compared with the levels of these biomarkers in SHAM rats. Four weeks of bilateral PVN injection of AMPK activator AICAR, attenuated the NE level and SBP, increased the expression of p-AMPK and p-AMPK/AMPK, lessened the NF-κB p65 activity, decreased the expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R in the PVN of 2K1C rats. Data from this study imply that the activation of AMPK within the PVN suppressed AT1-R expression through inhibiting the ERK1/2-NF-κB pathway, decreased the activity of the sympathetic nervous system, improved hypertension.
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Proteínas Quinasas Activadas por AMP , Modelos Animales de Enfermedad , Activación Enzimática , Hipertensión Renovascular , Proteína Quinasa 3 Activada por Mitógenos , Núcleo Hipotalámico Paraventricular , Ratas Sprague-Dawley , Receptor de Angiotensina Tipo 1 , Animales , Núcleo Hipotalámico Paraventricular/metabolismo , Núcleo Hipotalámico Paraventricular/enzimología , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Núcleo Hipotalámico Paraventricular/fisiopatología , Hipertensión Renovascular/fisiopatología , Hipertensión Renovascular/enzimología , Hipertensión Renovascular/metabolismo , Hipertensión Renovascular/tratamiento farmacológico , Masculino , Proteínas Quinasas Activadas por AMP/metabolismo , Fosforilación , Receptor de Angiotensina Tipo 1/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Factor de Transcripción ReIA/metabolismo , Ribonucleótidos/farmacología , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Sistema Nervioso Simpático/fisiopatología , Sistema Nervioso Simpático/efectos de los fármacos , Sistema Nervioso Simpático/metabolismo , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacología , FN-kappa B/metabolismo , Transducción de Señal , Antihipertensivos/farmacología , RatasRESUMEN
Accumulating evidence suggests that electroacupuncture (EA) has obvious therapeutic effects and unique advantages in alleviating myocardial ischemia-reperfusion injury (MIRI), while the underlying neuromolecular mechanisms of EA intervention for MIRI have not been fully elucidated. The aim of the study is to investigate the role of the neural pathway of hypothalamic paraventricular nucleus (PVN) neurons projecting to the rostral ventrolateral medulla (RVLM) in the alleviation of MIRI rats by EA preconditioning. MIRI models were established by ligating the left anterior descending coronary artery for 30 min followed by reperfusion for 2 h. Electrocardiogram recording, chemogenetics, enzyme-linked immunosorbent assay, multichannel physiology recording and haematoxylin-eosin and immunofluorescence staining methods were conducted to demonstrate that the firing frequencies of neurons in the PVN and the expression of c-Fos decreased by EA pretreatment. Meanwhile, EA preconditioning significantly reduced the levels of creatine kinase isoenzymes (CK-MB), cardiac troponin I (cTnI) and lactic dehydrogenase (LDH). Virus tracing showed a projection connection between PVN and RVLM. The inhibition of the PVN-RVLM neural pathway could replicate the protective effect of EA pretreatment on MIRI rats. However, the activation of the pathway weakened the effect of EA preconditioning. EA pretreatment alleviated MIRI by regulating PVN neurons projecting to RVLM. This work provides novel evidence of EA pretreatment for alleviating MIRI.
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Electroacupuntura , Bulbo Raquídeo , Daño por Reperfusión Miocárdica , Neuronas , Núcleo Hipotalámico Paraventricular , Ratas Sprague-Dawley , Animales , Electroacupuntura/métodos , Núcleo Hipotalámico Paraventricular/metabolismo , Bulbo Raquídeo/metabolismo , Bulbo Raquídeo/fisiología , Masculino , Neuronas/fisiología , Neuronas/metabolismo , Daño por Reperfusión Miocárdica/terapia , Daño por Reperfusión Miocárdica/metabolismo , Ratas , Vías Nerviosas/fisiología , Vías Nerviosas/metabolismo , Troponina I/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismoRESUMEN
Abdominal visceral pain is a predominant symptom in patients with chronic pancreatitis (CP); however, the underlying mechanism of pain in CP remains elusive. We hypothesized that astrocytes in the hypothalamic paraventricular nucleus (PVH) contribute to CP pain pathogenesis. A mouse model of CP was established by repeated intraperitoneal administration of caerulein to induce abdominal visceral pain. Abdominal mechanical stimulation, open field and elevated plus maze tests were performed to assess visceral pain and anxiety-like behavior. Fiber photometry, brain slice Ca2+ imaging, electrophysiology, and immunohistochemistry were used to investigate the underlying mechanisms. Mice with CP displayed long-term abdominal mechanical allodynia and comorbid anxiety, which was accompanied by astrocyte glial fibrillary acidic protein reactivity, elevated Ca2+ signaling, and astroglial glutamate transporter-1 (GLT-1) deficits in the PVH. Specifically, reducing astrocyte Ca2+ signaling in the PVH via chemogenetics significantly rescued GLT-1 deficits and alleviated mechanical allodynia and anxiety in mice with CP. Furthermore, we found that GLT-1 deficits directly contributed to the hyperexcitability of VGLUT2PVH neurons in mice with CP, and that pharmacological activation of GLT-1 alleviated the hyperexcitability of VGLUT2PVH neurons, abdominal visceral pain, and anxiety in these mice. Taken together, our data suggest that dysfunctional astrocyte glutamate uptake in the PVH contributes to visceral pain and anxiety in mice with CP, highlighting GLT-1 as a potential therapeutic target for chronic pain in patients experiencing CP.
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Background: Long term hypertension seriously promotes target organ damage in the brain and heart, and has increasingly become serious public health problem worldwide. The anti-hypertensive effects of capsaicin has been reported, however, the role and mechanism of capsaicin within the brain on salt-induced hypertension have yet to be elucidated. This study aimed to verify the hypothesis that capsaicin attenuates salt-induced hypertension via the AMPK/Akt/Nrf2 pathway in hypothalamic paraventricular nucleus (PVN). Methods: Dahl salt-sensitive (Dahl S) rats were used as animal model for the present study. Rats were randomly divided into four groups based on their dietary regimen (0.3% normal salt diet and 8% high salt diet) and treatment methods (infusion of vehicle or capsaicin in the PVN). Capsaicin was chronically administered in the PVN throughout the animal experiment phase of the study that lasted 6 weeks. Results: Our results demonstrated that PVN pretreatment with capsaicin can slow down raise of the blood pressure elevation and heart rate (HR) of Dahl S hypertensive rats given high salt diet. Interestingly, the cardiac hypertrophy was significantly improved. Furthermore, PVN pretreatment with capsaicin induced decrease in the expression of mRNA expression of NADPH oxidase-2 (NOX2), inducible nitric oxide synthase (iNOS), NOX4, p-IKKß and proinflammatory cytokines and increase in number of positive cell level for Nrf2 and HO-1 in the PVN of Dahl S hypertensive rats. Additionally, the protein expressions of phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase-B (p-AKT) were decreased, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were increased after the PVN pretreatment with capsaicin. Conclusion: Capsaicin pretreatment attenuates salt-sensitive hypertension by alleviating AMPK/Akt/iNOS pathway in the PVN.
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BACKGROUND: In the hypothalamic paraventricular nucleus (PVN) of spontaneously hypertensive rats (SHRs), the expression of the testis-specific protein, Y-encoded-like 2 (TSPYL2) and the phosphorylation level of Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) are higher comparing with the normotensive Wistar Kyoto rats (WKY). But how they are involved in hypertension remains unclear. TSPYL2 may interact with JAK2/STAT3 in PVN to sustain high blood pressure during hypertension. METHODS: Knockdown of TSPYL2 via adeno-associated virus (AAV) carrying shRNA was conducted through bilateral microinjection into the PVN of SHR and WKY rats. JAK2/STAT3 inhibition was achieved by intraperitoneally or PVN injection of AG490 into the SHRs. Blood pressure (BP), plasma norepinephrine (NE), PVN inflammatory response, and PVN oxidative stress were measured. RESULTS: TSPYL2 knock-down in the PVN of SHRs but not WKYs led to reduced BP and plasma NE, deactivation of JAK2/STAT3, decreased expression of pro-inflammatory cytokine IL-1ß, and increased expression of anti-inflammatory cytokine IL-10 in the PVN. Meanwhile, AG490 administrated in both ways reduced the BP in the SHRs and deactivated JAK2/STAT3 but failed to change the expression of TSPYL2 in PVN. AG490 also downregulated expression of IL-1ß and upregulated expression of IL-10. Both knockdown of TSPYL2 and inhibition of JAK2/STAT3 can reduce the oxidative stress in the PVN of SHRs. CONCLUSION: JAK2/STAT3 is regulated by TSPYL2 in the PVN of SHRs, and PVN TSPYL2/JAK2/STAT3 is essential for maintaining high BP in hypertensive rats, making it a potential therapeutic target for hypertension.
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Presión Sanguínea , Hipertensión , Janus Quinasa 2 , Núcleo Hipotalámico Paraventricular , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Factor de Transcripción STAT3 , Transducción de Señal , Animales , Janus Quinasa 2/metabolismo , Factor de Transcripción STAT3/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Núcleo Hipotalámico Paraventricular/enzimología , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Hipertensión/metabolismo , Hipertensión/fisiopatología , Masculino , Modelos Animales de Enfermedad , Estrés Oxidativo/efectos de los fármacos , Norepinefrina/metabolismo , Ratas , Tirfostinos/farmacología , FosforilaciónRESUMEN
Activation of the renin-angiotensin system (RAS) triggers oxidative stress and an inflammatory response in the hypothalamic paraventricular nucleus (PVN), in turn increasing the sympathetic hyperactivity that is a major cause of hypertension. Pyridostigmine has cardioprotective effects by suppressing the RAS of myocardial tissue. However, whether pyridostigmine attenuates hypertension by inhibiting the RAS of the PVN remains unclear. We thus investigated the effect and mechanism of pyridostigmine on two-kidney one-clip (2K1C)-induced hypertension. 2K1C rats received pyridostigmine, or not, for 8 weeks. Cardiovascular function, hemodynamic parameters, and autonomic activity were measured. The PVN levels of pro-/anti-inflammatory cytokines, oxidative stress, and RAS signaling molecules were evaluated. Our results showed that hypertension was accompanied by cardiovascular dysfunction and an autonomic imbalance characterized by enhanced sympathetic but diminished vagal activity. The PVN levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS), NOX-2, and malondialdehyde (MDA) increased; those of IL-10 and superoxide dismutase (SOD) decreased. Moreover, the RAS signaling pathway was activated, as evidenced by increased levels of the angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and the Ang II type 1 receptor (AT1R) and a decreased AT2R level. Pyridostigmine lowered blood pressure and improved cardiovascular function, associated with restoration of the autonomic balance. Meanwhile, pyridostigmine decreased PVN IL-6, TNF-α, ROS, NOX-2, and MDA levels and increased IL-10 and SOD levels. Additionally, pyridostigmine suppressed PVN ACE, Ang II, and AT1R levels and increased AT2R expression. Pyridostigmine attenuated hypertension by inhibiting PVN oxidative stress and inflammation induced by the RAS.
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Paroxysmal sympathetic hyperactivity (PSH) is a common clinical feature secondary to ischemic stroke (IS), but its mechanism is poorly understood. We aimed to investigate the role of H2S in the pathogenesis of PSH. IS patients were divided into malignant (MCI) and non-malignant cerebral infarction (NMCI) group. IS in rats was induced by the right middle cerebral artery occlusion (MCAO). H2S donor (NaHS) or inhibitor (aminooxy-acetic acid, AOAA) were microinjected into the hypothalamic paraventricular nucleus (PVN). Compared with the NMCI group, patients in the MCI group showed PSH, including tachycardia, hypertension, and more plasma norepinephrine (NE) that was positively correlated with levels of creatine kinase, glutamate transaminase, and creatinine respectively. The 1-year survival rate of patients with high plasma NE levels was lower. The hypothalamus of rats with MCAO showed increased activity, especially in the PVN region. The levels of H2S in PVN of the rats with MCAO were reduced, while the blood pressure and renal sympathetic discharge were increased, which could be ameliorated by NaHS and exacerbated by AOAA. NaHS completely reduced the disulfide bond of NMDAR1 in PC12 cells. The inhibition of NMDAR by MK-801 microinjected in PVN of rats with MCAO also could lower blood pressure and renal sympathetic discharge. In conclusion, PSH may be associated with disease progression and survival in patients with IS. Decreased levels of H2S in PVN were involved in regulating sympathetic efferent activity after cerebral infarction. Our results might provide a new strategy and target for the prevention and treatment of PSH.
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Sulfuro de Hidrógeno , Núcleo Hipotalámico Paraventricular , Animales , Núcleo Hipotalámico Paraventricular/metabolismo , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Sulfuro de Hidrógeno/metabolismo , Sulfuro de Hidrógeno/sangre , Masculino , Ratas , Humanos , Anciano , Infarto Cerebral , Persona de Mediana Edad , Ratas Sprague-Dawley , Femenino , Norepinefrina/sangre , Enfermedades del Sistema Nervioso Autónomo , Ácido Aminooxiacético/farmacología , Sistema Nervioso Simpático/fisiopatología , Sistema Nervioso Simpático/efectos de los fármacos , Infarto de la Arteria Cerebral Media/complicaciones , Presión Sanguínea/efectos de los fármacosRESUMEN
BACKGROUND: Oxidative stress and inflammatory cytokines in the hypothalamus paraventricular nucleus (PVN) have been implicated in sympathetic nerve activity and the development of hypertension, but the specific mechanisms underlying their production in the PVN remains to be elucidated. Previous studies have demonstrated that activation of nuclear transcription related factor-2 (Nrf2) in the PVN reduced the production of reactive oxygen species (ROS) and inflammatory mediators. Moreover, AMP-activated protein kinase (AMPK), has been observed to decrease ROS and inflammatory cytokine production when activated in the periphery. 5-amino-1-ß-D-ribofuranosyl-imidazole-4-carboxamide (AICAR) is an AMPK agonist. However, little research has been conducted on the role of AMPK in the PVN during hypertension. Therefore, we hypothesized that AICAR in the PVN is involved in regulating AMPK/Nrf2 pathway, affecting ROS and inflammatory cytokine expression, influencing sympathetic nerve activity. METHODS: Adult male Sprague-Dawley rats were utilized to induce two-kidney, one-clip (2K1C) hypertension via constriction of the right renal artery. Bilateral PVN was microinjected with either artificial cerebrospinal fluid or AICAR once a day for 4 weeks. RESULTS: Compared to the SHAM group, the PVN of 2K1C hypertensive rats decreased p-AMPK and p-Nrf2 expression, increased Fra-Like, NAD(P)H oxidase (NOX)2, NOX4, tumor necrosis factor-α and interleukin (IL)-1ß expression, elevated ROS levels, decreased superoxide dismutase 1 and IL-10 expression, and elevated plasma norepinephrine levels. Bilateral PVN microinjection of AICAR significantly ameliorated these changes. CONCLUSION: These findings suggest that repeated injection of AICAR in the PVN suppresses ROS and inflammatory cytokine production through the AMPK/Nrf2 pathway, reducing sympathetic nerve activity and improving hypertension.
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Proteínas Quinasas Activadas por AMP , Aminoimidazol Carboxamida , Hipertensión , Factor 2 Relacionado con NF-E2 , Núcleo Hipotalámico Paraventricular , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno , Ribonucleótidos , Transducción de Señal , Animales , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Núcleo Hipotalámico Paraventricular/metabolismo , Masculino , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacología , Aminoimidazol Carboxamida/administración & dosificación , Ribonucleótidos/farmacología , Ribonucleótidos/administración & dosificación , Proteínas Quinasas Activadas por AMP/metabolismo , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Ratas , Transducción de Señal/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Presión Sanguínea/efectos de los fármacos , Sistema Nervioso Simpático/efectos de los fármacos , Sistema Nervioso Simpático/metabolismo , Estrés Oxidativo/efectos de los fármacos , Citocinas/metabolismoRESUMEN
Guo, Xinqi, Hongyu Ma, Ziye Cui, Qiyue Zhao, Ying Zhang, Lu Jia, Liping Zhang, Hui Guo, Xiangjian Zhang, Yi Zhang, Yue Guan, and Huijie Ma. Chronic intermittent hypobaric hypoxia reduces hypothalamic N-Methyl-d-Aspartate Receptor activity and sympathetic outflow in spontaneously hypertensive rats. High Alt Med Biol. 25:77-88, 2024. Objective: This study aims to determine the role of hypothalamic renin-angiotensin system (RAS) in the antihypertensive effect of chronic intermittent hypobaric hypoxia (CIHH). Methods: Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) received 35 days of hypobaric hypoxia simulating an altitude of 4,000 m, 5 h/day. The levels of RAS, blood pressure, and N-methyl-d-aspartate receptor (NMDAR) activities of hypothalamic paraventricular nucleus (PVN) presympathetic neurons from each group of rats were determined. Results: The systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure (MAP) of SHRs significantly decreased from the third week of CIHH treatment. This blood pressure reduction effect could be maintained for at least 2 weeks after stopping the CIHH treatment. CIHH treatment also attenuated the decrease in MAP and renal sympathetic nerve activity induced by hexamethonium administration in SHRs, but not in WKY rats. Furthermore, CIHH reversed the increase in serum angiotensin (Ang)II concentration and the expression of PVN angiotensin-converting enzyme (ACE) and AngII type 1 (AT1) receptors, as well as the decrease in serum Ang1-7 concentration and the expression of PVN ACE2 and Mas receptors in SHRs. In addition, the administration of CIHH resulted in a reduction in the frequency of miniature excitatory postsynaptic currents and amplitude of NMDAR current in PVN presympathetic neurons of SHRs, which means that CIHH decreased the pre- and postsynaptic NMDAR activity of PVN presympathetic neurons in SHRs. However, pretreatment with A779 (a Mas receptor blocker) or AngII abrogated the above effects. Meanwhile, Ang1-7 pretreatment mimicked the CIHH effect on pre- and postsynaptic NMDAR activity of presympathetic neurons in SHRs. Conclusions: Our data indicate that CIHH reduces pre- and postsynaptic NMDAR activity of PVN presympathetic neurons, sympathetic outflow, and blood pressure by decreasing the activity of the ACE/AngII/AT1 axis and increasing the activity of ACE2/Ang1-7/Mas axis in the hypothalamus in hypertension.
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Hipertensión , Receptores de N-Metil-D-Aspartato , Ratas , Animales , Ratas Endogámicas SHR , Receptores de N-Metil-D-Aspartato/metabolismo , Ratas Endogámicas WKY , Enzima Convertidora de Angiotensina 2/metabolismo , Hipotálamo , Hipertensión/etiología , Hipertensión/terapia , Presión Sanguínea/fisiología , Sistema Nervioso Simpático/metabolismo , Angiotensinas/metabolismo , Angiotensinas/farmacologíaRESUMEN
Background: Glucagon-like peptide 1 (GLP-1) is involved in the regulation of energy and glucose homeostasis. As GLP-1 has similar effects on the energy homeostasis as the hypophysiotropic thyrotropin-releasing hormone (TRH) neurons that regulate the hypothalamic-pituitary-thyroid (HPT) axis, we raised the possibility that the TRH neurons are involved in the mediation of the effects of GLP-1. Therefore, the relationship and interaction of the GLP-1 system and the TRH neurons of the hypothalamic paraventricular nucleus (PVN) were studied. Methods: To examine the anatomical and functional relationship of TRH neurons and the GLP-1 system in the PVN, immunocytochemistry, in situ hybridization, in vitro patch-clamp electrophysiology, metabolic phenotyping, and explant experiments were performed. Results: Our data demonstrate that the TRH neurons of the PVN are innervated by GLP-1 producing neurons and express the GLP-1 receptor (GLP-1R). However, not only do the GLP-1-innervated TRH neurons express GLP-1R but the receptor is also present in the axons of the hypophysiotropic TRH neurons in the blood-brain barrier free median eminence (ME) suggesting that peripherally derived GLP-1 may also influence the TRH neurons. In vitro, GLP-1 increased the firing rate of TRH neurons and depolarized them. In addition, GLP-1 directly stimulated the GABAergic input of a population of TRH neurons. Furthermore, GLP-1 inhibited the release of TRH from the hypophysiotropic axons in the ME. In vivo, peripheral GLP-1R agonist administration markedly inhibited the food intake and the energy expenditure, but had no effect on the TRH expression in the PVN and resulted in lower circulating free T4 levels. Conclusions: Our results indicate that GLP-1R activation has a direct stimulatory effect on TRH neurons in the PVN, but the activation of GLP-1R may also inhibit TRH neurons by facilitating their inhibitory inputs or by inhibiting the axon terminals of these cells in the ME. The innervation of TRH neurons by GLP-1 neurons suggests that TRH neurons might be influenced by both circulating GLP-1 and by GLP-1 neurons of the nucleus tractus solitarii. The lack of GLP-1R agonist-induced regulation of TRH neurons in vivo suggests that the HPT axis does not mediate the GLP-1R agonist-induced weight loss.
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Receptor del Péptido 1 Similar al Glucagón , Hormona Liberadora de Tirotropina , Ratones , Masculino , Animales , Hormona Liberadora de Tirotropina/metabolismo , Neuronas/metabolismo , Axones/metabolismo , Núcleo Hipotalámico Paraventricular , Péptido 1 Similar al Glucagón/metabolismo , Péptido 1 Similar al Glucagón/farmacologíaRESUMEN
BACKGROUND: Our previous study showed that light-emitting diode modulation of the hypothalamic paraventricular nucleus (PVN), which is the control center of the sympathetic nervous system, might attenuate neuroinflammation in the PVN and prevent ventricular arrhythmias (VAs) after myocardial infarction (MI). Low-intensity focused ultrasound (LIFU) has deeper penetration than does light-emitting diode, while its effect on the PVN has not been reported. OBJECTIVE: This study aimed to explore the effect of LIFU modulation of the PVN on the inducibility of post-MI VAs. METHODS: Fifty-four Sprague-Dawley rats were randomly divided into acute control (n = 12, 22.22%), acute MI (AMI, n = 12, 22.22%), AMI + LIFU (n = 12, 22.22%), chronic control (n = 6, 11.11%), chronic MI (CMI, n = 6, 11.11%), and CMI + LIFU (n = 6, 11.11%) groups. MI was induced by left anterior artery ligation, and electrocardiographic recording for 0.5 hours after MI and programmed electrophysiological stimulation were used to test the vulnerability of VAs. Peripheral sympathetic neural activity was assessed by measuring left stellate ganglion neural activity. Finally, hearts and brains were extracted for Western blotting and histopathological analysis, respectively. RESULTS: Compared with the AMI group, AMI-induced VAs (P < .05) and left stellate ganglion neural activity (P < .05) were significantly attenuated in the AMI + LIFU group. In addition, LIFU resulted in a significant reduction of microglial activation in the PVN and expression of inflammatory cytokines in the peri-ischemic myocardium. In the CMI + LIFU group, there was no obvious tissue damage in the brain. CONCLUSION: LIFU modulation of the PVN may prevent the incidence of post-MI VAs by attenuating MI-induced sympathetic neural activation and inflammatory response.
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Infarto del Miocardio , Núcleo Hipotalámico Paraventricular , Ratas , Animales , Núcleo Hipotalámico Paraventricular/metabolismo , Ratas Sprague-Dawley , Arritmias Cardíacas/etiología , Arritmias Cardíacas/prevención & control , CorazónRESUMEN
Objective:To explore the feature of FOS expression in oxytocin-and vasopressin-positive neurons in the hypothalamic paraventricular nucleus(PVN)under different status of diabetes mellitus(DM).Methods:Intraperito-neal injection of vehicle or STZ in mice was conducted to establish control or diabetes model.Mechanical sensitivity was evaluated by von Frey filament tests to distinguish diabetic neuropathic pain(DNP)from without-pain group(DWP).The expression of FOS,oxytocin(OXT)-and vasopressin(VP)-positive neurons,as well as their double labeling was detected by immunohistochemical and immunofluorescent staining.Cell counting and comparison were made in groups.Results:FOS expression was easily detected in the PVN in the three groups(Control group,DNP group and DWP group)at 7 days,while that in DWP and DNP groups at 28 days was hardly detectable,with the number being signifi-cantly different from the 7 days group(P＜0.05 or 0.001).Likewise,compared with the control group,immunofluo-rescent signals for VP and OXT staining in the DNP and DWP groups also showed a trend of weakening as the modeling time increased(P＜0.05).The cell counting after double staining for VP or OXT with FOS showed that,in the DWP group at 7 days,the number of VP and FOS double-labeled neurons was 74.33±22.10,accounting for(56.64± 7.52)％of VP-positive cells,whereas the double labeling rate for OXT and FOS was only(10.44±3.14)％.In the DNP group at 7 days,the number of OXT and FOS double-labeled neurons was 51.00±31.80,accounting for(18.50 ±9.51)％of OXT-positive neurons,whereas the double labeling rate for VP and FOS was only(9.34±3.27)％.In contrast to these changes in 7 days group,the expression of FOS decreased sharply in the group of 28 days,thereby al-most no double-labeled neurons.Conclusion:The plasticity changes of oxytocin-and vasopressin-positive neurons in the PVN are different depending on the status of pain and non-pain,and the stage of disease progression.Understanding the changes is of great significance for unravelling the neural mechanism of diabetes and its complications.
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Chronic stress induces depression and insulin resistance, between which there is a bidirectional relationship. However, the mechanisms underlying this comorbidity remain unclear. White adipose tissue (WAT), innervated by sympathetic nerves, serves as a central node in the interorgan crosstalk through adipokines. Abnormal secretion of adipokines is involved in mood disorders and metabolic morbidities. We describe here a brain-sympathetic nerve-adipose circuit originating in the hypothalamic paraventricular nucleus (PVN) with a role in depression and insulin resistance induced by chronic stress. PVN neurons are labelled after inoculation of pseudorabies virus (PRV) into WAT and are activated under restraint stress. Chemogenetic manipulations suggest a role for the PVN in depression and insulin resistance. Chronic stress increases the sympathetic innervation of WAT and downregulates several antidepressant and insulin-sensitizing adipokines, including leptin, adiponectin, Angptl4 and Sfrp5. Chronic activation of the PVN has similar effects. ß-adrenergic receptors translate sympathetic tone into an adipose response, inducing downregulation of those adipokines and depressive-like behaviours and insulin resistance. We finally show that AP-1 has a role in the regulation of adipokine expression under chronic stress.
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Resistencia a la Insulina , Núcleo Hipotalámico Paraventricular , Ratas , Animales , Núcleo Hipotalámico Paraventricular/metabolismo , Ratas Sprague-Dawley , Depresión , Obesidad/metabolismo , Adipoquinas/metabolismo , Adipoquinas/farmacologíaRESUMEN
BACKGROUND: Hypertension has seriously affected a large part of the adult and elderly population. The complications caused by hypertension are important risk factors for cardiovascular disease accidents. Capsaicin, a pungent component of chili pepper has been revealed to improve hypertension. However, its potential mechanism in improving hypertension remains to be explored. PURPOSE: In the present study, we aimed to investigate whether capsaicin could attenuate the SIRT1/NF-κB/MAPKs pathway in the paraventricular nucleus of hypothalamus (PVN). METHODS: We used spontaneous hypertensive rats (SHRs) as animal model rats. Micro osmotic pump was used to give capsaicin through PVN for 28 days, starting from age12-week-old. RESULTS: The results showed that capsaicin significantly reduced blood pressure from the 16th day of infusion onward. At the end of the experimental period, we measured cardiac hypertrophy index and the heart rate (HR), and the results showed that the cardiac hypertrophy and heart rate of rats was significantly improved upon capsaicin chronic infusion. Norepinephrine (NE) and epinephrine (EPI) in plasma of SHRs treated with capsaicin were also decreased. Additionally, capsaicin increased the protein expression and number of positive cells of SIRT1 and the 67-kDa isoform of glutamate decarboxylase (GAD67), decreased the production of reactive oxygen species (ROS), number of positive cells of NOX2, those of Angiotensin Converting Enzyme (ACE) and p-IKKß, tyrosine hydroxylase (TH), the gene expression levels of NOX4 and pro-inflammatory cytokines. Capsaicin also decreased the relative protein expressions of protein in MAPKs pathway. CONCLUSION: Current data indicated that capsaicin within the PVN improves hypertension and cardiac hypertrophy via SIRT1/NF-κB/MAPKs pathway in the PVN of SHRs, supporting its potential as candidate drug for preventing and improving hypertension.
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Hipertensión , FN-kappa B , Anciano , Humanos , Ratas , Animales , FN-kappa B/metabolismo , Núcleo Hipotalámico Paraventricular , Capsaicina/farmacología , Sirtuina 1/metabolismo , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo , Cardiomegalia/tratamiento farmacológico , Cardiomegalia/metabolismo , Ratas Endogámicas SHRRESUMEN
BACKGROUND: Luteolin is widely distributed among a number of vegetal species worldwide. The pharmacological effects of luteolin are diverse and amongst antioxidant, free radical scavenging, and anti-inflammatory activities. Preliminary study showed that luteolin can ameliorate hypertension. However, the precise mechanism needs further investigation. There is no evidence that luteolin affects the paraventricular nucleus of the hypothalamus (PVN), a brain nucleus associated with a critical neural regulator of blood pressure. Our main aim was to explore the effect of luteolin on the PI3K/Akt/NF-κB signaling pathway within the PVN of hypertensive rats. METHODS: spontaneously hypertensive rats (SHRs) and corresponding normotensive control rats, the Wistar Kyoto (WKY) rats were divided into four groups and subsequently treated for 4 weeks with bilateral PVN injections of either luteolin (20 µg/0.11 µL, volume: 0.11 µL/h) or vehicle (artificial cerebrospinal fluid). RESULTS: luteolin infusion to the PVN significantly decreased some hemodynamic parameters including the mean arterial pressure (MAP), heart rate (HR), circulating plasma norepinephrine (NE) and epinephrine (EPI). Additionally, there was a decrease in the expressions of the phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase-B (p-AKT), levels of reactive oxygen species (ROS), NAD(P)H oxidase subunit (NOX2, NOX4) in the PVN of SHRs. Meanwhile, the expression of inflammatory cytokines and the activity of nuclear factor κB (NF-κB) p65 in the PVN of SHRs were lowered. Furthermore, immunofluorescence results showed that injection of luteolin in the PVN reduced the expression of tyrosine hydroxylase (TH), and increased that of superoxide dismutase (SOD1) and the 67-kDa isoform of glutamate decarboxylase (GAD67) in the PVN of SHRs. CONCLUSION: Our novel findings revealed that luteolin lowered hypertension via inhibiting NF-κB-mediated inflammation and PI3K/Akt signaling pathway in the PVN.
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Hipertensión , FN-kappa B , Ratas , Animales , FN-kappa B/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Luteolina/farmacología , Luteolina/uso terapéutico , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Endogámicas WKY , Transducción de Señal , Ratas Endogámicas SHR , Inflamación/metabolismo , Sistema Nervioso SimpáticoRESUMEN
Proinflammatory cytokines, reactive oxygen species and imbalance of neurotransmitters are involved in the pathophysiology of angiotensin II-induced hypertension. The hypothalamic paraventricular nucleus (PVN) plays a vital role in hypertension. Evidences show that microglia are activated and release proinflammatory cytokines in angiocardiopathy. We hypothesized that angiotensin II induces PVN microglial activation, and the activated PVN microglia release proinflammatory cytokines and cause oxidative stress through nuclear factor-kappa B (NF-κB) pathway, which contributes to sympathetic overactivity and hypertension. Male Sprague-Dawley rats (weight 275-300 g) were infused with angiotensin II to induce hypertension. Then, rats were treated with bilateral PVN infusion of microglial activation inhibitor minocycline, NF-κB activation inhibitor pyrrolidine dithiocarbamate or vehicle for 4 weeks. When compared to control groups, angiotensin II-induced hypertensive rats had higher mean arterial pressure, PVN proinflammatory cytokines, and imbalance of neurotransmitters, accompanied with PVN activated microglia. These rats also had more PVN gp91phox (source of reactive oxygen species production), and NF-κB p65. Bilateral PVN infusion of minocycline or pyrrolidine dithiocarbamate partly or completely ameliorated these changes. This study indicates that angiotensin II-induced hypertensive rats have more activated microglia in PVN, and activated PVN microglia release proinflammatory cytokines and result in oxidative stress, which contributes to sympathoexcitation and hypertensive response. Suppression of activated PVN microglia by minocycline or pyrrolidine dithiocarbamate attenuates inflammation and oxidative stress, and improves angiotensin II-induced hypertension, which indicates that activated microglia promote hypertension through activated NF-κB. The findings may offer hypertension new strategies.
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Hipertensión , Minociclina , Ratas , Masculino , Animales , Minociclina/efectos adversos , Microglía/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Especies Reactivas de Oxígeno/efectos adversos , Especies Reactivas de Oxígeno/metabolismo , FN-kappa B/metabolismo , Angiotensina II/efectos adversos , Angiotensina II/metabolismo , Ratas Sprague-Dawley , Hipertensión/tratamiento farmacológico , Citocinas/metabolismo , Neurotransmisores/efectos adversos , Neurotransmisores/metabolismoRESUMEN
Aim To observe the effect of corticotropin-releasing factor ( CRF) -expressing neurons on presympathetic neurons in hypothalamic paraventricular nucleus ( PVN) of normotensive Wistar Kyoto ( WKY) rats or spontaneously hypertensive rats (SHR) , and to elucidate the underlying neuronal circuit mechanism of central sympathetic hyperexcitability. Methods The expression levels of CRF protein in WKY rats and SHR PVN were determined by Western blot. Meanwhile, the WKY and SHR PVN CRF-expressing neurons and presympathetic neurons were observed by immunofluo-rescent staining. Adult WKY rats and SHR were used in this study. By microinjection of Cre-dependent ade-no-associated viruses ( AAV) that specifically recognized the CRF promoter and AAV of chemogenetics into the PVN, CRF-expressing neurons expressed designer receptors exclusively activated by designer drugs (DREADDs). Human M3 muscarinic DREADD coupled to Gq receptor ( hM3 Dq) was specifically expressed in PVN CRF-expressing neurons in WKY rats, while human M4 muscarinic DREADD coupled to Gi receptor ( hM4Di) was specifically expressed in PVN CRF-expressing neurons in SHR. Clozapine-N-oxide (CNO) , as a designer ligand, would couple to excitatory hM3Dq or inhibitory hM4Di to regulate the excitability of PVN CRF-expressing neurons. Then the PVN presympathetic neurons were retrogradely labeled by microinjection of fluosecent tracer into the intermedio-lateral column (IML) of spinal cord. Lastly, whole cell patch clamp was used to determine the effect of CNO (10 jjumol L~ ) on spontaneous excitatory postsynaptic currents ( sEPSCs) and current-evoked firing of PVN presympathtic neurons of WKY rats and SHR. Results The expression of CRF protein in the PVN of SHR was significantly higher than that of WKY rats, and the activity and number of CRF-expressing neurons in the PVN of SHR were increased. PVN CRF-expressing neurons were expressed with chemogenetic DREADDs and PVN presympathetic neurons were retrogradely labeled with fluorescent tracer in WKY rats and SHR. In SHR expressed with chemogenetic inhibitory hM4Di-mCherry of PVN CRF-expressing neurons, bath application of CNO to the brain slices resulted in a significant decrease in sEPSCs frequency, but no change in their amplitude of labeled PVN presympathetic neurons. In contrast, in WKY rats expressed with excitatory hM3Dq-eGFP of PVN CRF-expressing neurons, CNO had no obvious effect on the sEPSCs frequency and amplitude in PVN presympathetic neurons. Furthermore, bath application of CNO had no significant effect on current-evoked firing of PVN presympathetic neurons of either WKY rats with hM3Dq-eGFP expression in CRF neurons or SHR with hM4Di-mCherry expression in CRF neurons. Conclusions The activity and number of PVN CRF-expressing neurons are increased in SHR, and CRF-expressing neurons enhance the excitability of presympathetic neurons, which acts as a regulatory neuronal microcircuit between CRF neurons and presympathetic neurons in the PVN.
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AIM: To assess the effect of curcumin in hypothalamic paraventricular nucleus (PVN) and mean arterial pressure so as to explore the central mechanism of hypertension. METHODS: Sixty Sprague-Dawley rats which body weights between 170 and 190 grams fed with a normal salt (0.3% NaCl) or a high salt (8% NaCl) diet for 6 weeks. Meanwhile half of each team received curcumin administration or vehicle by intragastric administration. Mean Arterial pressure was measured noninvasively via tail-cuff instrument and their recording system. The PVN tissue samPles were collected and stored at −80 °C for later analyses. We performed the following experimental procedures: Western blot analysis, immunofluorescence, immunofluorescence and statistical analysis. RESULTS:The average arterial blood Pressure of rats in the high-salt diet group was significantly reduced after 6 weeks of curcumin intervention. The levels of NOX2, NOX4, TLR4, MyD88, IL-6, IL-1β, MCP-1 and ROS in the long-term high-salt diet grouP were significantly higher after curcumin intervention. CONCLUSION:Curcumin can improve blood pressure in hypertensive rats induced by long-term high salt, the mechanism may be related to the imProvement of oxidative stress and inflammatory cytokines in the paraventricular nucleus of the hypothalamus.