RESUMEN
The l -arginine ( l -Arg)/nitric oxide/cyclic GMP/potassium channel (K ATP ) pathway and opioid receptors are known to play critical roles in pain perception and the antinociceptive effects of various compounds. While there is evidence suggesting that the analgesic effects of rutin may involve nitric oxide modulation, the direct link between rutin and the l -Arg/nitric oxide/cyclic GMP/K ATP pathway in the context of pain modulation requires further investigation. The antinociceptive effect of rutin was studied in male NMRI mice using the formalin test. To investigate the role of the l -Arg/nitric oxide/cyclic GMP/K ATP pathway and opioid receptors, the mice were pretreated intraperitoneally with different substances. These substances included l -Arg (a precursor of nitric oxide), S-nitroso- N -acetylpenicillamine (SNAP, a nitric oxide donor), N(gamma)-nitro- l -arginine methyl ester (L-NAME, an inhibitor of nitric oxide synthase), sildenafil (an inhibitor of phosphodiesterase enzyme), glibenclamide (a K ATP channel blocker), and naloxone (an opioid receptor antagonist). All pretreatments were administered 20â min before the administration of the most effective dose of rutin. Based on our investigation, it was found that rutin exhibited a dose-dependent antinociceptive effect. The administration of SNAP enhanced the analgesic effects of rutin during both the initial and secondary phases. Moreover, L-NAME, naloxone, and glibenclamide reduced the analgesic effects of rutin in both the primary and secondary phases. In conclusion, rutin holds significant value as a flavonoid with analgesic properties, and its analgesic effect is directly mediated through the nitric oxide/cyclic GMP/K ATP channel pathway.
Asunto(s)
Analgésicos , Arginina , GMP Cíclico , Canales KATP , NG-Nitroarginina Metil Éster , Óxido Nítrico , Receptores Opioides , Rutina , Transducción de Señal , Animales , Masculino , Ratones , Arginina/farmacología , Óxido Nítrico/metabolismo , Rutina/farmacología , Analgésicos/farmacología , Transducción de Señal/efectos de los fármacos , Receptores Opioides/metabolismo , Receptores Opioides/efectos de los fármacos , Canales KATP/metabolismo , GMP Cíclico/metabolismo , NG-Nitroarginina Metil Éster/farmacología , Gliburida/farmacología , Citrato de Sildenafil/farmacología , Dimensión del Dolor/efectos de los fármacos , Dimensión del Dolor/métodos , Naloxona/farmacología , Sulfonas/farmacología , Piperazinas/farmacología , Purinas/farmacología , S-Nitroso-N-Acetilpenicilamina/farmacología , Dolor/tratamiento farmacológico , Dolor/metabolismo , Antagonistas de Narcóticos/farmacología , Relación Dosis-Respuesta a Droga , Donantes de Óxido Nítrico/farmacologíaRESUMEN
BACKGROUND: Antidiabetic therapies are effective, but could indirectly modify the inflammatory response in the ocular microenvironment; therefore, a study was developed to evaluate the inflammatory cytokine profile in the vitreous humor of diabetic patients with retinopathy under treatment with antidiabetic drugs. METHODS: Observational, comparative, retrospective, cross-sectional study. Interleukins 1ß, 6, 8, 10, and tumor necrosis factor-alpha (TNFα) were evaluated in the vitreous humor obtained from patients with type 2 diabetes mellitus, proliferative diabetic retinopathy, and concomitant retinal detachment or vitreous hemorrhage, and who were already on antidiabetic treatment with insulin or metformin + glibenclamide. The quantification analysis of each cytokine was performed by the cytometric bead array (CBA) technique; medians and interquartile ranges were obtained, and the results were compared between groups using the Mann-Whitney U test, where a p-value < 0.05 was considered significant. RESULTS: Thirty-eight samples; quantification of TNFα concentrations was higher in the group of patients administered insulin, while interleukin-8 was lower; in the metformin + glibenclamide combination therapy group, it occurred inversely. In the stratified analysis, the highest concentrations of interleukin-8 and TNFα occurred in patients with vitreous hemorrhage; however, the only statistical difference existed in patients with retinal detachment, whose TNFα concentration in the combined therapy group was the lowest value found (53.50 (33.03-86.66), p = 0.03). Interleukins 1ß, 6, and 10 were not detected. CONCLUSION: Interleukin-8 and TNFα concentrations are opposite between treatment groups; this change is more accentuated in patients with proliferative diabetic retinopathy and vitreous hemorrhage, where the highest concentrations of both cytokines are found, although only TNFα have statistical difference.
Asunto(s)
Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Hipoglucemiantes , Interleucina-8 , Factor de Necrosis Tumoral alfa , Cuerpo Vítreo , Humanos , Retinopatía Diabética/tratamiento farmacológico , Retinopatía Diabética/metabolismo , Masculino , Cuerpo Vítreo/metabolismo , Femenino , Persona de Mediana Edad , Estudios Transversales , Factor de Necrosis Tumoral alfa/metabolismo , Estudios Retrospectivos , Hipoglucemiantes/uso terapéutico , Anciano , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Interleucina-8/metabolismo , Insulina/uso terapéutico , Metformina/uso terapéutico , Gliburida/uso terapéutico , Quimioterapia CombinadaRESUMEN
BACKGROUND: Recently, we demonstrated that nicorandil inhibits mechanical allodynia induced by paclitaxel. In the present study, we evaluated the effect induced by nicorandil in a model of neuropathic pain induced by chronic constriction injury (CCI) in mice. We also investigated putative mechanisms underlying such an effect. METHODS: CCI was induced by three ligatures of the left sciatic nerve. Mechanical allodynia was evaluated by measuring the paw withdrawal threshold with an electronic von Frey apparatus. Concentrations of cytokines and myeloperoxidase activity were determined in the paw tissue, sciatic nerve, and dorsal root ganglia (DRG). RESULTS: Oral administration of two doses of nicorandil (150 mg/kg po), but not equimolar doses of nicotinamide or nicotinic acid, attenuated mechanical allodynia induced by CCI. Nicorandil activity was reduced by previous administration of glibenclamide (40 mg/kg) or naltrexone (5 mg/kg or 10 mg/kg). Two doses of nicorandil (150 mg/kg, po) reduced tumor necrosis factor-α, interleukin-1ß and interleukin-6, but not CXCL-1, concentrations in the paw tissue of CCI mice. Two doses of nicorandil (150 mg/kg, po) reduced concentrations of all these mediators in the sciatic nerve and DRG. Two doses of nicorandil (150 mg/kg, po) also reduced the myeloperoxidase activity in the paw tissue, sciatic nerve, and DRG. CONCLUSIONS: Nicorandil exhibits antiallodynic activity in a model of neuropathic pain induced by CCI. Inhibition of cytokines production and reduction of neutrophils recruitment in paw tissue, sciatic nerve, and DRG as well as activation of ATP-dependent potassium channels and opioidergic pathways, underlie nicorandil antiallodynic activity.
Asunto(s)
Citocinas , Modelos Animales de Enfermedad , Ganglios Espinales , Hiperalgesia , Canales KATP , Neuralgia , Nicorandil , Nervio Ciático , Animales , Nicorandil/farmacología , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , Ganglios Espinales/metabolismo , Ganglios Espinales/efectos de los fármacos , Ratones , Nervio Ciático/efectos de los fármacos , Nervio Ciático/metabolismo , Masculino , Citocinas/metabolismo , Canales KATP/metabolismo , Hiperalgesia/tratamiento farmacológico , Hiperalgesia/metabolismo , Gliburida/farmacología , Naltrexona/farmacología , Naltrexona/análogos & derivados , Peroxidasa/metabolismo , Infiltración Neutrófila/efectos de los fármacos , Analgésicos/farmacologíaRESUMEN
Lymphatic dysfunction is an underlying component of multiple metabolic diseases, including diabetes, obesity, and metabolic syndrome. We investigated the roles of KATP channels in lymphatic contractile dysfunction in response to acute metabolic stress induced by inhibition of the mitochondrial electron transport chain. Ex vivo popliteal lymphatic vessels from mice were exposed to the electron transport chain inhibitors antimycin A and rotenone, or the oxidative phosphorylation inhibitor/protonophore, CCCP. Each inhibitor led to a significant reduction in the frequency of spontaneous lymphatic contractions and calculated pump flow, without a significant change in contraction amplitude. Contraction frequency was restored by the KATP channel inhibitor, glibenclamide. Lymphatic vessels from mice with global Kir6.1 deficiency or expressing a smooth muscle-specific dominant negative Kir6.1 channel were resistant to inhibition. Antimycin A inhibited the spontaneous action potentials generated in lymphatic muscle and this effect was reversed by glibenclamide, confirming the role of KATP channels. Antimycin A, but not rotenone or CCCP, increased dihydrorhodamine fluorescence in lymphatic muscle, indicating ROS production. Pretreatment with tiron or catalase prevented the effect of antimycin A on wild-type lymphatic vessels, consistent with its action being mediated by ROS. Our results support the conclusion that KATP channels in lymphatic muscle can be directly activated by reduced mitochondrial ATP production or ROS generation, consequent to acute metabolic stress, leading to contractile dysfunction through inhibition of the ionic pacemaker controlling spontaneous lymphatic contractions. We propose that a similar activation of KATP channels contributes to lymphatic dysfunction in metabolic disease.
Asunto(s)
Canales KATP , Vasos Linfáticos , Contracción Muscular , Estrés Fisiológico , Animales , Canales KATP/metabolismo , Ratones , Vasos Linfáticos/metabolismo , Vasos Linfáticos/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Estrés Fisiológico/fisiología , Estrés Fisiológico/efectos de los fármacos , Gliburida/farmacología , Ratones Endogámicos C57BL , Especies Reactivas de Oxígeno/metabolismo , Antimicina A/farmacología , MasculinoRESUMEN
Glyburide, a sulfonylurea drug used to treat type 2 diabetes, boasts neuroprotective effects by targeting the sulfonylurea receptor 1 (SUR1) and associated ion channels in various cell types, including those in the central nervous system and the retina. Previously, we demonstrated that glyburide therapy improved retinal function and structure in a rat model of diabetic retinopathy. In the present study, we explore the application of glyburide in non-neovascular ("dry") age-related macular degeneration (AMD), another progressive disease characterized by oxidative stress-induced damage and neuroinflammation that trigger cell death in the retina. We show that glyburide administration to a human cone cell line confers protection against oxidative stress, inflammasome activation, and apoptosis. To corroborate our in vitro results, we also conducted a case-control study, controlling for AMD risk factors and other diabetes medications. It showed that glyburide use in patients reduces the odds of new-onset dry AMD. A positive dose-response relationship is observed from this analysis, in which higher cumulative doses of glyburide further reduce the odds of new-onset dry AMD. In the quest for novel therapies for AMD, glyburide emerges as a promising repurposable drug given its known safety profile. The results from this study provide insights into the multifaceted actions of glyburide and its potential as a neuroprotective agent for retinal diseases; however, further preclinical and clinical studies are needed to validate its therapeutic potential in the context of degenerative retinal disorders such as AMD.
Asunto(s)
Gliburida , Degeneración Macular , Fármacos Neuroprotectores , Estrés Oxidativo , Humanos , Gliburida/farmacología , Gliburida/uso terapéutico , Degeneración Macular/tratamiento farmacológico , Degeneración Macular/prevención & control , Fármacos Neuroprotectores/uso terapéutico , Fármacos Neuroprotectores/farmacología , Estrés Oxidativo/efectos de los fármacos , Masculino , Femenino , Apoptosis/efectos de los fármacos , Anciano , Línea Celular , Estudios de Casos y Controles , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Células Fotorreceptoras Retinianas Conos/patología , Neuroprotección/efectos de los fármacos , Inflamasomas/metabolismo , Inflamasomas/efectos de los fármacosRESUMEN
Objective: Potassium channels have an important role in the vascular adaptation during pregnancy and a reduction in the expression of adenosine triphosphate-sensitive potassium channels (Katp) has been linked to preeclampsia. Activation of Katp induces vasodilation; however, no previous study has been conducted to evaluate the effects of the inhibition of these channels in the contractility of preeclamptic arteries. Glibenclamide is an oral antihyperglycemic agent that inhibits Katp and has been widely used in vascular studies. Methods: To investigate the effects of the inhibition of Katp, umbilical arteries of preeclamptic women and women with healthy pregnancies were assessed by vascular contractility experiments, in the presence or absence of glibenclamide. The umbilical arteries were challenged with cumulative concentrations of potassium chloride (KCl) and serotonin. Results: There were no differences between the groups concerning the maternal age and gestational age of the patients. The percentage of smokers, caucasians and primiparae per group was also similar. On the other hand, blood pressure parameters were elevated in the preeclamptic group. In addition, the preeclamptic group presented a significantly higher body mass index. The newborns of both groups presented similar APGAR scores and weights. Conclusion: In the presence of glibenclamide, there was an increase in the KCl-induced contractions only in vessels from the PE group, showing a possible involvement of these channels in the disorder.
Asunto(s)
Gliburida , Preeclampsia , Arterias Umbilicales , Humanos , Femenino , Embarazo , Preeclampsia/fisiopatología , Arterias Umbilicales/fisiopatología , Adulto , Gliburida/farmacología , Vasoconstricción/efectos de los fármacos , Adulto Joven , Canales KATP/metabolismo , Cloruro de Potasio/farmacologíaRESUMEN
During diabetes progression, ß-cell dysfunction due to loss of potassium channels sensitive to ATP, known as KATP channels, occurs, contributing to hyperglycemia. The aim of this study was to investigate if KATP channel expression or activity in the nervous system was altered in a high-fat diet (HFD)-fed mouse model of diet-induced obesity. Expression of two KATP channel subunits, Kcnj11 (Kir6.2) and Abcc8 (SUR1), were decreased in the peripheral and central nervous system of mice fed HFD, which was significantly correlated with mechanical paw-withdrawal thresholds. HFD mice had decreased antinociception to systemic morphine compared with control diet (CON) mice, which was expected because KATP channels are downstream targets of opioid receptors. Mechanical hypersensitivity in HFD mice was exacerbated after systemic treatment with glyburide or nateglinide, KATP channel antagonists clinically used to control blood glucose levels. Upregulation of SUR1 and Kir6.2, through an adenovirus delivered intrathecally, increased morphine antinociception in HFD mice. These data present a potential link between KATP channel function and neuropathy during early stages of diabetes. There is a need for increased knowledge of how diabetes affects structural and molecular changes in the nervous system, including ion channels, to lead to the progression of chronic pain and sensory issues.
Asunto(s)
Dieta Alta en Grasa , Canales KATP , Obesidad , Canales de Potasio de Rectificación Interna , Receptores de Sulfonilureas , Animales , Obesidad/metabolismo , Dieta Alta en Grasa/efectos adversos , Ratones , Canales KATP/metabolismo , Canales KATP/genética , Canales de Potasio de Rectificación Interna/metabolismo , Canales de Potasio de Rectificación Interna/genética , Masculino , Receptores de Sulfonilureas/metabolismo , Receptores de Sulfonilureas/genética , Ratones Endogámicos C57BL , Morfina/farmacología , Analgésicos Opioides/farmacología , Gliburida/farmacología , Modelos Animales de EnfermedadRESUMEN
Oral bioavailability of glibenclamide (Glb) was appreciably improved by the formation of an amorphous solid dispersion with Poloxamer-188 (P-188). Poloxamer-188 substantially enhanced the solubility and thereby the dissolution rate of the biopharmaceutics classification system (BCS) class II drug Glb and simultaneously exhibited a better stabilizing effect of the amorphous solid dispersion prepared by the solvent evaporation method. The physical state of the dispersed Glb in the polymeric matrix was characterized by differential scanning calorimetry, X-ray diffraction, scanning electron microscope and Fourier transform infrared studies. In vitro drug release in buffer (pH 7.2) revealed that the amorphous solid dispersion at a Glb-P-188 ratio of 1:6 (SDE4) improved the dissolution of Glb by 90% within 3 h. A pharmacokinetic study of the solid dispersion formulation SDE4 in Wistar rats showed that the oral bioavailability of the drug was greatly increased as compared with the market tablet formulation, Daonil®. The formulation SDE4 resulted in an AUC0-24h ~2-fold higher. The SDE4 formulation was found to be stable during the study period of 6 months.
Asunto(s)
Disponibilidad Biológica , Gliburida , Poloxámero , Ratas Wistar , Animales , Gliburida/farmacocinética , Gliburida/química , Gliburida/sangre , Gliburida/administración & dosificación , Ratas , Masculino , Poloxámero/química , Poloxámero/farmacocinética , Estabilidad de Medicamentos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Difracción de Rayos X/métodos , Rastreo Diferencial de Calorimetría , SolubilidadRESUMEN
El estudio presenta el caso de una mujer de 47 años con diabetes tipo 2 (DM-II), hipertensión y anemia, tratada con metformina, glibenclamida, metoprolol y hierro/ácido fólico. Se identificó una interacción farmacológica entre glibenclamida y metoprolol, causando síntomas de hipoglucemia por la tarde. La evaluación mediante la Escala de Probabilidad de Interacciones Farmacológicas (EPIF) de Horn sugirió una interacción probable. El análisis farmacocinético reveló que el tiempo en el cual se alcanzan las concentraciones máximas de ambos fármacos coincidía con el inicio de los síntomas. Se implementó un nuevo horario de medicación que resolvió los síntomas. La interacción farmacológica se atribuyó al bloqueo de los efectos adrenérgicos por el metoprolol, comprometiendo la capacidad de contrarrestar la acción de la insulina liberada por la glibenclamida. Se resalta la importancia de la vigilancia, la toma de decisiones informadas y la implementación de estrategias preventivas para garantizar la seguridad y eficacia del tratamiento farmacológico en pacientes con condiciones clínicas específicas, como la DM-II y enfermedades cardiovasculares concomitantes.(AU)
Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Receptores de Sulfonilureas , Antagonistas Adrenérgicos beta , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Gliburida/uso terapéutico , Metoprolol/uso terapéutico , Examen Físico , Pacientes Internos , Farmacéuticos , Servicios Comunitarios de FarmaciaRESUMEN
OBJECTIVE: The purpose of this study was to describe the impact of enteral glyburide on cerebral edema formation and hypoglycemia when used to treat patients diagnosed with acute ischemic stroke (AIS). METHODS: This study was a single-center, retrospective medical record review that included all patients aged ≥18 years diagnosed with AIS who received ≥1 dose of enteral glyburide for the prevention of cerebral edema from January 1, 2018 to March 31, 2022. The primary outcome was the percentage of patients requiring intervention for cerebral edema management after glyburide initiation, and the safety outcome was the occurrence of hypoglycemia in this patient population. RESULTS: The final evaluation included 44 patients, with 6 patients (14%) requiring intervention for cerebral edema after glyburide initiation. The average baseline National Institutes of Health stroke scale score was 19. Overall, in-hospital mortality was 36% (n = 17), and hypoglycemia occurred in 7 patients (15%). Of the 44 patients, 20 (45%) received a partial duration of enteral glyburide (1-4 doses) and 24 (55%) received a full duration of enteral glyburide (5-7 doses). The rate of intervention for cerebral edema (10% vs. 17%) and the incidence of hypoglycemia (5% vs. 23%) were lower in the partial duration than in the full duration group. The in-hospital all-cause mortality rate was higher in the partial duration group than in the full duration group (43% vs. 31%). CONCLUSIONS: Despite the relatively low rates of intervention for cerebral edema, hypoglycemia was common, especially for patients receiving 5-7 doses of enteral glyburide for the prevention of cerebral edema after moderate-to-severe AIS.
Asunto(s)
Edema Encefálico , Gliburida , Hipoglucemiantes , Accidente Cerebrovascular Isquémico , Humanos , Edema Encefálico/prevención & control , Edema Encefálico/etiología , Femenino , Masculino , Gliburida/uso terapéutico , Gliburida/administración & dosificación , Accidente Cerebrovascular Isquémico/prevención & control , Anciano , Persona de Mediana Edad , Estudios Retrospectivos , Hipoglucemiantes/uso terapéutico , Hipoglucemiantes/administración & dosificación , Administración Oral , Anciano de 80 o más Años , Hipoglucemia/prevención & control , Mortalidad Hospitalaria , AdultoRESUMEN
Cytoprotection has emerged as an effective therapeutic strategy for mitigating brain injury following acute ischemic stroke (AIS). The sulfonylurea receptor 1-transient receptor potential M4 (SUR1-TRPM4) channel plays a pivotal role in brain edema and neuroinflammation. However, the practical use of the inhibitor glyburide (GLB) is hindered by its low bioavailability. Additionally, the elevated reactive oxygen species (ROS) after AIS exacerbate SUR1-TRPM4 activation, contributing to irreversible brain damage. To overcome these challenges, GLB and superoxide dismutase (SOD) were embedded in a covalent organic framework (COF) with a porous structure and great stability. The resulting S/G@COF demonstrated significant improvements in survival and neurological functions. This was achieved by eliminating ROS, preventing neuronal loss and apoptosis, suppressing neuroinflammation, modulating microglia activation, and ameliorating blood-brain barrier (BBB) disruption. Mechanistic investigations revealed that S/G@COF concurrently activated the Wnt/ß-catenin signaling pathway while suppressing the upregulation of SUR1-TRPM4. This study underscores the potential of employing multi-target therapy and drug modification in cytoprotective strategies for ischemic stroke.
Asunto(s)
Accidente Cerebrovascular Isquémico , Estructuras Metalorgánicas , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Estructuras Metalorgánicas/metabolismo , Estructuras Metalorgánicas/farmacología , Enfermedades Neuroinflamatorias , Especies Reactivas de Oxígeno/metabolismo , Barrera Hematoencefálica , Gliburida/metabolismo , Gliburida/farmacología , Gliburida/uso terapéutico , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/metabolismoRESUMEN
OBJECTIVE: Methyl-2-(4-chloro- phenyl)-5-benzoxazoleacetate (MCBA), a synthetic benzoxazole derivative with established antipsoriatic efficacy, was investigated for potential antinociceptive effects. This study employs various nociceptive assays in mice to elucidate MCBA's antinociceptive mechanisms. MATERIALS AND METHODS: MCBA's antinociceptive potential was tested against various nociception models induced by formalin, glutamate, capsaicin, a transient receptor potential vanilloid 1 (TRPV1) receptor agonist, and phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator. It was then assessed using the hot plate test and examined within the acetic acid-induced writhing test. During the acetic acid-induced writhing test, MCBA was pre-challenged against selective receptor antagonists such as naloxone, caffeine, atropine, yohimbine, ondansetron, and haloperidol. It was also pre-challenged with ATP-sensitive potassium channel inhibitor (glibenclamide) to further elucidate its antinociceptive mechanism. RESULTS: The results showed that oral administration of MCBA led to a dose-dependent and significant inhibition (p < 0.05) of nociceptive effects across all evaluated models at doses of 60, 120, and 240 mg/kg. Moreover, the efficacy of MCBA's antinociceptive potential was significantly counteracted (p < 0.0001) by specific antagonists: (i) directed at adenosinergic, alpha-2 adrenergic, and cholinergic receptors using caffeine, yohimbine, and atropine, respectively; and (ii) targeting ATP-sensitive potassium channels, employing glibenclamide. Antagonists aimed at opioidergic and serotoninergic receptors (naloxone and ondansetron, respectively) had poor utility in inhibiting antinociceptive activity. Conversely, the dopaminergic receptor antagonist haloperidol potentiated locomotor abnormalities associated with MCBA treatment. CONCLUSIONS: MCBA-induced antinociception involves modulation of glutamatergic-, TRVP1 receptors- and PKC-signaling pathways. It impacts adenosinergic, alpha-2 adrenergic, and cholinergic receptors and opens ATP-sensitive potassium channels.
Asunto(s)
Cafeína , Gliburida , Animales , Ratones , Haloperidol , Nocicepción , Ondansetrón , Adrenérgicos , Atropina , Canales KATP , Naloxona/farmacología , Receptores Colinérgicos , Yohimbina , Analgésicos/farmacología , AcetatosRESUMEN
Vascular smooth muscle KATP channels critically regulate blood flow and blood pressure by modulating vascular tone and therefore represent attractive drug targets for treating several cardiovascular disorders. However, the lack of potent inhibitors that can selectively inhibit Kir6.1/SUR2B (vascular KATP) over Kir6.2/SUR1 (pancreatic KATP) has eluded discovery despite decades of intensive research. We therefore screened 47,872 chemically diverse compounds for novel inhibitors of heterologously expressed Kir6.1/SUR2B channels. The most potent inhibitor identified in the screen was an N-aryl-N'-benzyl urea compound termed VU0542270. VU0542270 inhibits Kir6.1/SUR2B with an IC50 of approximately 100 nM but has no apparent activity toward Kir6.2/SUR1 or several other members of the Kir channel family at doses up to 30 µM (>300-fold selectivity). By expressing different combinations of Kir6.1 or Kir6.2 with SUR1, SUR2A, or SUR2B, the VU0542270 binding site was localized to SUR2. Initial structure-activity relationship exploration around VU0542270 revealed basic texture related to structural elements that are required for Kir6.1/SUR2B inhibition. Analysis of the pharmacokinetic properties of VU0542270 showed that it has a short in vivo half-life due to extensive metabolism. In pressure myography experiments on isolated mouse ductus arteriosus vessels, VU0542270 induced ductus arteriosus constriction in a dose-dependent manner similar to that of the nonspecific KATP channel inhibitor glibenclamide. The discovery of VU0542270 provides conceptual proof that SUR2-specific KATP channel inhibitors can be developed using a molecular target-based approach and offers hope for developing cardiovascular therapeutics targeting Kir6.1/SUR2B. SIGNIFICANCE STATEMENT: Small-molecule inhibitors of vascular smooth muscle KATP channels might represent novel therapeutics for patent ductus arteriosus, migraine headache, and sepsis; however, the lack of selective channel inhibitors has slowed progress in these therapeutic areas. Here, this study describes the discovery and characterization of the first vascular-specific KATP channel inhibitor, VU0542270.
Asunto(s)
Canales KATP , Animales , Ratones , Gliburida , Canales KATP/antagonistas & inhibidores , Músculo Liso Vascular/metabolismo , Receptores de Sulfonilureas/antagonistas & inhibidoresRESUMEN
AIMS/HYPOTHESIS: The ATP-sensitive potassium (KATP) channel couples beta cell electrical activity to glucose-stimulated insulin secretion. Loss-of-function mutations in either the pore-forming (inwardly rectifying potassium channel 6.2 [Kir6.2], encoded by KCNJ11) or regulatory (sulfonylurea receptor 1, encoded by ABCC8) subunits result in congenital hyperinsulinism, whereas gain-of-function mutations cause neonatal diabetes. Here, we report a novel loss-of-function mutation (Ser118Leu) in the pore helix of Kir6.2 paradoxically associated with sulfonylurea-sensitive diabetes that presents in early adult life. METHODS: A 31-year-old woman was diagnosed with mild hyperglycaemia during an employee screen. After three pregnancies, during which she was diagnosed with gestational diabetes, the patient continued to show elevated blood glucose and was treated with glibenclamide (known as glyburide in the USA and Canada) and metformin. Genetic testing identified a heterozygous mutation (S118L) in the KCNJ11 gene. Neither parent was known to have diabetes. We investigated the functional properties and membrane trafficking of mutant and wild-type KATP channels in Xenopus oocytes and in HEK-293T cells, using patch-clamp, two-electrode voltage-clamp and surface expression assays. RESULTS: Functional analysis showed no changes in the ATP sensitivity or metabolic regulation of the mutant channel. However, the Kir6.2-S118L mutation impaired surface expression of the KATP channel by 40%, categorising this as a loss-of-function mutation. CONCLUSIONS/INTERPRETATION: Our data support the increasing evidence that individuals with mild loss-of-function KATP channel mutations may develop insulin deficiency in early adulthood and even frank diabetes in middle age. In this case, the patient may have had hyperinsulinism that escaped detection in early life. Our results support the importance of functional analysis of KATP channel mutations in cases of atypical diabetes.
Asunto(s)
Hiperinsulinismo Congénito , Diabetes Gestacional , Canales de Potasio de Rectificación Interna , Recién Nacido , Adulto , Persona de Mediana Edad , Femenino , Embarazo , Humanos , Canales de Potasio de Rectificación Interna/genética , Receptores de Sulfonilureas/genética , Receptores de Sulfonilureas/metabolismo , Hiperinsulinismo Congénito/genética , Compuestos de Sulfonilurea/uso terapéutico , Mutación/genética , Gliburida , Adenosina Trifosfato/metabolismoRESUMEN
OBJECTIVE: This study aimed to investigate the impact of physical solid dispersions of spray-dried glibenclamide (SG) on the surface of microcrystalline cellulose (MC) and mannitol (M) surfaces, as well as their combination with phosphatidylcholine (P), on enhancing the dissolution rate of glibenclamide (G). METHODS: Solid dispersions were prepared using varying proportions of 1:1, 1:4, and 1:10 for SG on the surface of MC (SGA) and M (SGM), and then combined with P, in a proportion of 1:4:0.02 using spray drying. The particle size, specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and dissolution rate of SGA and SGM were characterized. RESULTS: SEM analysis revealed successful adhesion of SG onto the surface of the carrier surfaces. XRD showed reduced crystalline characteristic peaks for SGA, while SGM exhibited a sharp peaks pattern. Both SGA and SGM demonstrated higher dissolution rates compared to SG and G alone. Furthermore, the dissolution rates of the solid dispersions of SG, MC and P (SGAP), and SG, M, and P (SGMP) were sequentially higher than that of SGA and SGM. CONCLUSIONS: The study suggests that physical solid dispersions of SG on MC and M, along with their combination with P, can effectively enhance the dissolution rate of G. These findings may be valuable in developing of oral solid drug dosage forms utilizing SGA, SGM, SGAP, and SGMP.
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Celulosa , Gliburida , Manitol , Fosfatidilcolinas , Solubilidad , Difracción de Rayos X , Rastreo Diferencial de CalorimetríaRESUMEN
PURPOSE: To determine the effect of gallic acid or its combination with glibenclamide on some biochemical markers and histology of the cornea of streptozotocin (STZ) induced diabetic rats. METHODS: Following induction of diabetes, 24 male albino rats were divided into four groups of six rats each. Groups 1 and 2 (control and diabetic) received rat pellets and distilled water; group 3 (gallic acid) received rat pellets and gallic acid (10 mg/kg, orally) dissolved in the distilled water; and group 4 (gallic acid + glibenclamide) received rat pellets, gallic acid (10 mg/kg, orally), and glibenclamide (5 mg/kg, orally) dissolved in the distilled water. The treatments were administered for three months after which the rats were sacrificed after an overnight fast. Blood and sera were collected for the determination of biochemical parameters, while their eyes were excised for histology. RESULTS: STZ administration to the rats induced insulin resistance, hyperglycemia, microprotenuria, loss of weight, oxidative stress, inflammation, and alteration of their cornea histology, which was abolished following supplementation with gallic acid or its combination with glibenclamide. CONCLUSIONS: The study showed the potentials of gallic acid and glibenclamide in mitigating systemic complication and histological changes in the cornea of diabetic rats induced with STZ.
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Diabetes Mellitus Experimental , Gliburida , Ratas , Masculino , Animales , Gliburida/efectos adversos , Hipoglucemiantes/efectos adversos , Ácido Gálico/efectos adversos , Estreptozocina/efectos adversos , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Córnea/patología , Agua/efectos adversos , GlucemiaRESUMEN
OBJECTIVE: To evaluate the bronchodilatory mechanism of Astragalus sarcocolla (ASE) extract on tracheal smooth muscles of rabbits. STUDY DESIGN: In-vitro experimental study. Place and Duration of the Study: The animal house of CMH Lahore Medical College, Lahore, and Institute of Dentistry, NUMS, from October 2022 to May 2023. METHODOLOGY: Six rabbits were randomly divided into four groups. After euthanising the rabbit, the trachea was carefully dissected out and stabilised in Kreb's Henseleit solution for 30 minutes and then, stimulated by acetylcholine (Ach) 1µm, under mimicked physiological conditions. Group I served as the control group with tracheal smooth muscles stabilised with 1g tension. In Group II (positive control), tracheal smooth muscles were stimulated by potassium chloride (KCl) (80 mM and 25 mM, respectively) to get maximum tracheal smooth muscle contractions. Later, the tissue was exposed to theophylline with three molar concentrations 0.2, 0.4, 0.6, and 0.8 mM, and cumulative dose response curves were formed. In Group III (ASE group), tracheal smooth muscles were stimulated by KCl (80 mM and 25 mM) and was exposed to increasing concentration of ASE. In group IV, tissue was stimulated by KCl (25 mM) and glibenclamide (3 µM), later exposed to increasing concentration of ASE to confirm the bronchodilatory mechanism. The change in isometric contraction of the tissue was recorded using the force displacement transducer connected to a PowerLab data acquisition system. Concentration response curves were drawn, and median effective concentrations (EC50 values) and percentage inhibition were calculated. Non-linear regression was applied for the analysis of the concentration-response curves. RESULTS: ASE inhibited the KCl-induced low potassium (25 mM) contractions (EC50 = 0.38 mg/ml, 95% CI: 0.04 - 0.38, n = 6). It only partially inhibited the high potassium-induced contractions in tracheal smooth muscles. Pretreatment with glibenclamide showed a rightward shift of the dose-response curve. Theophylline and ASE significantly reduced the low K+ induced smooth muscle contractions in comparison to the control group (p <0.001, each). CONCLUSION: Astragalus sarcocolla extract produced bronchodilator effects through the activation of ATP sensitive potassium channels in isolated rabbit trachea. KEY WORDS: Astragalus sarcocolla, Bronchodilators, ATP-sensitive potassium channels, Effective concentration 50, Concentration response curves.
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Planta del Astrágalo , Broncodilatadores , Humanos , Animales , Conejos , Broncodilatadores/farmacología , Teofilina , Gliburida , Potasio , Extractos Vegetales/farmacologíaRESUMEN
BACKGROUND: Gestational diabetes mellitus (GDM) poses significant risks during pregnancy for both mother and fetus. Adherence to oral antidiabetic medications, like glibenclamide (GB), can be challenging, necessitating novel drug delivery methods. Nanostructured lipid carriers (NLC) offer a promising approach by efficiently permeating the skin due to their small size and lipid-based composition. OBJECTIVE: This study aimed to develop and evaluate transdermal patches loaded with glibenclamide NLCs to treat GDM. METHODS: Glibenclamide NLCs were prepared using hot homogenization with ultrasonication and melt dispersion method. A central composite design was utilized to optimize the formulations. Transdermal patches containing optimized NLCs were developed using HPMC K 100 and Eudragit L polymers. The patches were evaluated for various parameters, and their pharmacokinetic and pharmacodynamic studies were carried out to assess their safety and efficacy. RESULTS: Optimized NLCs efficiently permeated rat skin. Cell viability studies indicated the nontoxicity of the formulations. NLC-loaded transdermal patches (F2 and F7) showed drug release of 1098 µg/cm2 and 1001.83 µg/cm2 in 24 h, with a 2.5-fold higher flux and permeation coefficient than the GB patch. Pharmacokinetic analysis revealed Tmax of 8 and 10 h and Cmax of 7127 ng/ml and 7960 ng/ml for F2 and F7, respectively, ensuring sustained drug action. AUC0-α was 625681 ng/ml·h and 363625 ng/ml·h for F2 and F7, respectively, indicating improved bioavailability. CONCLUSION: Transdermal patches incorporating NLCs hold promise for enhancing glibenclamide's therapeutic efficacy in GDM treatment. Improved skin permeation, sustained drug release, and enhanced bioavailability make NLC-based transdermal patches a potential alternative with better patient compliance.
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Administración Cutánea , Diabetes Gestacional , Portadores de Fármacos , Gliburida , Hipoglucemiantes , Lípidos , Nanoestructuras , Gliburida/administración & dosificación , Gliburida/farmacocinética , Gliburida/química , Animales , Diabetes Gestacional/tratamiento farmacológico , Femenino , Embarazo , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Lípidos/química , Lípidos/administración & dosificación , Ratas , Nanoestructuras/química , Nanoestructuras/administración & dosificación , Portadores de Fármacos/química , Parche Transdérmico , Absorción Cutánea , Liberación de Fármacos , Sistemas de Liberación de Medicamentos , Supervivencia Celular/efectos de los fármacos , Ratas WistarRESUMEN
BACKGROUND: Medicinal herbs are frequently used for the management of gastrointestinal disorders because they contain various compounds that can potentially amplify the intended therapeutic effects. Cuminaldehyde is a plant-based constituent found in oils derived from botanicals such as cumin, eucalyptus, myrrh, and cassia and is responsible for its health benefits. Despite the utilization of cuminaldehyde for several medicinal properties, there is currently insufficient scientific evidence to support its effectiveness in treating diarrhea. Hence, the present investigation was carried out to evaluate the antidiarrheal and antispasmodic efficacy of cuminaldehyde, with detailed pharmacodynamics explored. METHODS: An in vivo antidiarrheal test was conducted in mice following the castor oil-induced diarrhea model, while an isolated small intestine obtained from rats was used to evaluate the detailed mechanism(s) of antispasmodic effects. RESULTS: Cuminaldehyde, at 10 and 20 mg/kg, exhibited 60 and 80% protection in mice from episodic diarrhea compared to the saline control group, whereas this inhibitory effect was significantly reversed in the pretreated mice with glibenclamide, similar to cromakalim, an ATP-dependent K+ channel opener. In the ex vivo experiments conducted in isolated rat tissues, cuminaldehyde reversed the glibenclamide-sensitive low K+ (25 mM)-mediated contractions at significantly higher potency compared to its inhibitory effect against high K+ (80 mM), thus showing predominant involvement of ATP-dependent K+ activation followed by Ca++ channel inhibition. Cromakalim, a standard drug, selectively suppressed the glibenclamide-sensitive low K+-induced contractions, whereas no relaxation was observed against high K+, as expected. Verapamil, a Ca++ channel inhibitor, effectively suppressed both low and high K+-induced contractions with similar potency, as anticipated. At higher concentrations, the inhibitory effect of cuminaldehyde against Ca++ channels was further confirmed when the preincubated ileum tissues with cuminaldehyde (3 and 10 mM) in Ca++ free medium shifted CaCl2-mediated concentration-response curves (CRCs) towards the right with suppression of the maximum peaks, similar to verapamil, a standard Ca++ ion inhibitor. CONCLUSIONS: Present findings support the antidiarrheal and antispasmodic potential of cuminaldehyde, possibly by the predominant activation of ATP-dependent K+ channels followed by voltage-gated Ca++ inhibition. However, further in-depth assays are recommended to know the precise mechanism and to elucidate additional unexplored mechanism(s) if involved.
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Antidiarreicos , Benzaldehídos , Cimenos , Parasimpatolíticos , Ratas , Ratones , Animales , Antidiarreicos/efectos adversos , Parasimpatolíticos/efectos adversos , Cromakalim/efectos adversos , Gliburida/efectos adversos , Extractos Vegetales/farmacología , Yeyuno , Diarrea/inducido químicamente , Diarrea/tratamiento farmacológico , Verapamilo/efectos adversos , Adenosina TrifosfatoRESUMEN
Tramadol, an analgesic classified as an "atypical opioid", exhibits both opioid and non-opioid mechanisms of action. This study aimed to explore these mechanisms, specifically the opioid-, cannabinoid-, nitric oxide-, and potassium channel-based mechanisms, which contribute to the peripheral antinociception effect of tramadol, in an experimental rat model. The nociceptive threshold was determined using paw pressure withdrawal. To examine the mechanisms of action, several substances were administered intraplantarly: naloxone, a non-selective opioid antagonist (50 µg/paw); AM251 (80 µg/paw) and AM630 (100 µg/paw) as the selective antagonists for types 1 and 2 cannabinoid receptors, respectively; nitric oxide synthase inhibitors L-NOArg, L-NIO, L-NPA, and L-NIL (24 µg/paw); and the enzyme inhibitors of guanylatocyclase and phosphodiesterase of cGMP, ODQ, and zaprinast. Additionally, potassium channel blockers glibenclamide, tetraethylammonium, dequalinium, and paxillin were used. The results showed that opioid and cannabinoid receptor antagonists did not reverse tramadol's effects. L-NOarg, L-NIO, and L-NPA partially reversed antinociception, while ODQ completely reversed, and zaprinast enhanced tramadol's antinociception effect. Notably, glibenclamide blocked tramadol's antinociception in a dose-dependent manner. These findings suggest that tramadol's peripheral antinociception effect is likely mediated by the nitrergic pathway and sensitive ATP potassium channels, rather than the opioid and cannabinoid pathways.