RESUMEN
Cinnamic alcohol (CA) is a phenylpropanoid found in the essential oil of the bark of the genus Cinnamomum spp. Schaeff. (Lauraceae Juss.), known as cinnamon. To evaluate the neuroprotective effect of CA and its possible mechanism of action on mice submitted to the pentylenetetrazole (PTZ) induced epileptic seizures model. Behavioral, neurochemical, histomorphometric and immunohistochemistry analysis were carried out. The administration of CA (50-200 mg/kg, i.p., 30 min prior to PTZ and 0.7-25 mg/kg, i.p., 60 min prior to PTZ) increased the latency to seizure onset and the latency to death. The effects observed with CA treatment at 60 min were partially reversed by pretreatment with flumazenil. Furthermore, neurochemical assays indicated that CA reduced the concentration of malondialdehyde and nitrite, while increasing the concentration of reduced glutathione. Finally, histomorphometric and immunohistochemistry analysis revealed a reduction in inflammation and an increase in neuronal preservation in the hippocampi of CA pre-treated mice. Taken together, the results suggest that CA seems to modulate the GABAA receptor, decrease oxidative stress, mitigate neuroinflammation, and reduce cell death processes.
Asunto(s)
Cinnamomum , Fármacos Neuroprotectores , Aceites Volátiles , Animales , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Fármacos Neuroprotectores/aislamiento & purificación , Ratones , Aceites Volátiles/farmacología , Aceites Volátiles/uso terapéutico , Aceites Volátiles/aislamiento & purificación , Masculino , Cinnamomum/química , Pentilenotetrazol , Convulsiones/tratamiento farmacológico , Convulsiones/inducido químicamente , Convulsiones/metabolismo , Convulsiones/prevención & control , Estrés Oxidativo/efectos de los fármacos , Propanoles/farmacologíaRESUMEN
The purpose of this study was to investigate the mechanisms underlying sex differences in the role of spinal α6-subunit containing GABAA (α6GABAA) receptors in rats with neuropathic pain. Intrathecal 2,5-dihydro-7-methoxy-2-(4-methoxyphenyl)-3H-pyrazolo [4,3-c] quinoline-3-one (PZ-II-029, positive allosteric modulator of α6GABAA receptors) reduced tactile allodynia in female but not in male rats with neuropathic pain. PZ-II-029 was also more effective in females than males in inflammatory and nociplastic pain. Ovariectomy abated the antiallodynic effect of PZ-II-029 in neuropathic rats, whereas 17ß-estradiol or 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT), estradiol receptor-α agonist, restored the effect of PZ-II-029 in ovariectomized rats. Blockade of estradiol receptor-α, using MPP (1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy) phenol]-1H-pyrazole dihydrochloride), prevented the effect of 17ß-estradiol on PZ-II-029-induced antiallodynia in ovariectomized neuropathic females. Nerve injury reduced α6GABAA receptor protein expression at the dorsal root ganglia (DRG) and spinal cord of intact and ovariectomized female rats. In this last group, reconstitution with 17ß-estradiol fully restored its expression in DRG and spinal cord. In male rats, nerve injury reduced α6GABAA receptor protein expression only at the spinal cord. Nerve injury enhanced estradiol receptor-α protein expression at the DRG in intact non-ovariectomized rats. However, ovariectomy decreased estradiol receptor-α protein expression at the DRG. In the spinal cord there were no changes in estradiol receptor-α protein expression. 17ß-estradiol restored estradiol receptor-α protein expression at the DRG and increased it at the spinal cord of neuropathic rats. These data suggest that 17ß-estradiol modulates the expression and function of the α6GABAA receptor through its interaction with estradiol receptor-α in female rats.
Asunto(s)
Estradiol , Neuralgia , Receptores de GABA-A , Médula Espinal , Animales , Femenino , Estradiol/farmacología , Receptores de GABA-A/metabolismo , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , Ratas , Masculino , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismo , Hiperalgesia/tratamiento farmacológico , Hiperalgesia/metabolismo , Ovariectomía , Ratas Sprague-Dawley , Caracteres Sexuales , Receptor alfa de Estrógeno/metabolismo , Pirazoles/farmacologíaRESUMEN
Gamma-aminobutyric acid (GABA) disinhibition in medial hypothalamus (MH) nuclei of rats elicits some defensive reactions that are considered panic attack-like behaviours. Recent evidence showed that the norepinephrine-mediated system modulates fear-related defensive behaviours organised by MH neurons at least in part via noradrenergic receptors recruitment on midbrain tegmentum. However, it is unknown whether noradrenergic receptors of the MH also modulate the panic attack-like reactions. The aim of this work was to investigate the distribution of noradrenergic receptors in MH, and the effects of either α1-, α2- or ß-noradrenergic receptors blockade in the MH on defensive behaviours elaborated by hypothalamic nuclei. Defensive behaviours were evaluated after the microinjection of the selective GABAA receptor antagonist bicuculline into the MH that was preceded by microinjection of either WB4101, RX821002, propranolol (α1-, α2- and ß-noradrenergic receptor selective antagonists, respectively), or physiological saline into the MH of male Wistar rats. The α1-, α2- and ß-noradrenergic receptors were found in neuronal perikarya of all MH nuclei, and the α2-noradrenergic receptor were also found on glial cells mainly situated in the ventrolateral division of the ventromedial hypothalamic nucleus. The α1- and ß-noradrenergic receptors blockade in the MH decreased defensive attention and escape reactions elicited by the intra-MH microinjections of bicuculline. These findings suggest that, despite the profuse distributions of α1-, α2- and ß-noradrenergic receptors in the MH, both α1- and ß-noradrenergic receptor- rather than α2-noradrenergic receptor-signalling in MH are critical for the neuromodulation of panic-like behaviour.
Asunto(s)
Trastorno de Pánico , Ratas , Masculino , Animales , Núcleo Hipotalámico Ventromedial , Bicuculina/farmacología , Ratas Wistar , Transmisión Sináptica , MicroinyeccionesRESUMEN
Besides its function as a local mediator of the immune response, histamine can play a role as a neurotransmitter and neuromodulator. Histamine actions are classically mediated through four different G protein-coupled receptor subtypes but non-classical actions were also described, including effects on many ligand-gated ion channels. Previous evidence indicated that histamine acts as a positive modulator on diverse GABAA receptor subtypes, such as GABAAα1ß2γ2, GABAAα2ß3γ2, GABAAα3ß3γ2, GABAAα4ß3γ2 and GABAAα5ß3γ2. Meanwhile, its effects on GABAAρ1 receptors, known to stand for tonic currents in retinal neurons, had not been examined before. The effects of histamine on the function of human homomeric GABAAρ1 receptors were studied here, using heterologous expression in Xenopus laevis oocytes followed by the electrophysiological recording of GABA-evoked Cl- currents. Histamine inhibited GABAAρ1 receptor-mediated responses. Effects were reversible, independent of the membrane potential, and strongly dependent on both histamine and GABA concentration. A rightward parallel shift in the concentration-response curve for GABA was observed in the presence of histamine, without substantial change in the maximal response or the Hill coefficient. Results were compatible with a competitive antagonism of histamine on the GABAAρ1 receptors. This is the first report of inhibitory actions exerted by histamine on an ionotropic GABA receptor.
Asunto(s)
Histamina , Receptores de GABA-A , Humanos , Animales , Receptores de GABA-A/metabolismo , Histamina/farmacología , Histamina/metabolismo , Receptores de GABA , Fenómenos Electrofisiológicos , Ácido gamma-Aminobutírico/farmacología , Ácido gamma-Aminobutírico/metabolismo , Xenopus laevis/metabolismo , Oocitos/metabolismoRESUMEN
Neuroinflammation plays a protective role in the brain; however, in neurological diseases such as epilepsy, overactivated neuroinflammation, along with overexpression of inflammatory mediators, can cause neuronal tissue damage, which can trigger seizures due to loss of ionic or neurotransmitter homeostasis. Therefore, we aimed to evaluate mRNA expression levels of proinflammatory cytokines, early growth response factor 3 (Egr3), and GABA A receptors in the hippocampus of naive audiogenic mutant tremor mice, and stimulated tremor mice after a seizure. Gene expression of Il-1ß, Il-6, Tnf-α, Ccl2, Ccl3, Egr3, Gabra1, and Gabra4 from hippocampal samples of naive and stimulated tremor mice were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Relative to resistant mice, Ccl3 gene expression was increased and Il6 was decreased in the hippocampus of naïve tremor mice. Thirty minutes after a seizure, Ccl3 and Il-1ß mRNA expression were decreased (p < 0.0001; p = 0.0034, respectively) while Il6 was increased (p = 0.0052) in stimulated tremor mice, relative to naïve animals. In addition, Egr3, Gabra1, and Gabra4 mRNA expression was decreased in the hippocampus of naive tremor mice, relative to resistant mice, which increased 30 minutes after a seizure (p = 0.0496; p = 0.0447, and p = 0.0011, respectively), relative to naïve animals. In conclusion, overexpression of Ccl3 in the hippocampus of naive tremor mice, followed by downregulation soon after seizure in stimulated tremor mice, could be involved in changes in the blood-brain barrier (BBB) permeability in epilepsy. Il-1ß may be involved in hippocampal downregulation of GABA A receptors of naive tremor mice, characterizing an important mechanism in audiogenic seizures triggering. Hippocampal alterations of proinflammatory cytokines, Egr3, and GABA A receptors in tremor mice reinforce them as an alternative tool to modeling temporal lobe epilepsy.
Asunto(s)
Epilepsia Refleja , Receptores de GABA-A , Ratones , Animales , Receptores de GABA-A/metabolismo , Temblor/metabolismo , Convulsiones/genética , Hipocampo/metabolismo , Epilepsia Refleja/genética , ARN Mensajero , Quimiocina CCL3/genética , Quimiocina CCL3/metabolismoRESUMEN
Previous studies have been described changes in brain regions contributing to the sympathetic vasomotor overactivity in Goldblatt hypertension (2K1C). Furthermore, changes in the spinal cord are also involved in the cardiovascular and autonomic dysfunction in renovascular hypertension, as intrathecal (i.t.) administration of Losartan (Los) causes a robust hypotensive/sympathoinhibitory response in 2K1C but not in control rats. The present study evaluated the role of spinal γ-aminobutyric acid (GABA)-ergic inputs in the control of sympathetic vasomotor activity in the 2K1C rats. Hypertension was induced by clipping the renal artery. After six weeks, a catheter (PE-10) was inserted into the subarachnoid space and advanced to the T10-11 vertebral level in urethane-anaesthetized rats. The effects of i.t. injection of bicuculline (Bic) on blood pressure (BP), renal and splanchnic sympathetic nerve activity (rSNA and sSNA, respectively) were evaluated over 40 consecutive minutes in the presence or absence of spinal AT1 antagonism. I.t. Bic triggered a more intense pressor and sympathoexcitatory response in 2K1C rats, however, these responses were attenuated by previous i.t. Los. No differences in the gene expression of GAD 65 and GABA-A receptors subunits in the spinal cord segments were found. Thus, the sympathoexcitation induced by spinal GABA-A blockade is dependent of local AT1 receptor in 2K1C but not in control rats. Excitatory angiotensinergic inputs to sympathetic preganglionic neurons are tonic controlled by spinal GABAergic actions in Goldblatt hypertension.
Asunto(s)
Angiotensina II/metabolismo , Hipertensión Renovascular/tratamiento farmacológico , Losartán/farmacología , Sistema Nervioso Simpático/efectos de los fármacos , Ácido gamma-Aminobutírico/metabolismo , Animales , Bicuculina/farmacología , Presión Sanguínea/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Hipertensión Renovascular/fisiopatología , Masculino , Ratas Wistar , Receptor de Angiotensina Tipo 1/efectos de los fármacos , Receptor de Angiotensina Tipo 1/metabolismo , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismoRESUMEN
RATIONALE: The absence of ovarian hormones that is characteristic of natural and surgical postmenopause in women is frequently related to such disorders as depression and anxiety. Chronic treatment with the flavonoid chrysin was previously shown to exert antidepressant-like effects in rodents subjected to validate behavioral models. Chrysin has also been shown to have anxiolytic-like properties, but its antidepressant-like effects and mechanism of action in the absence of ovarian hormones remain unknown. OBJECTIVES: To compare the effects of the flavonoid chrysin with the effects of the neurosteroids progesterone and allopregnanolone on depression-like behavior in ovariectomized rats and evaluate the participation of γ-aminobutyric acid-A (GABAA) receptors in these actions. METHODS: Ovariectomized female Wistar rats were subjected to the locomotor activity test and forced swim test. The animals were assigned to eight treatment groups: vehicle, chrysin (1 mg/kg), progesterone (1 mg/kg), allopregnanolone (1 mg/kg), bicuculline (1 mg/kg), and pretreatment with bicuculline followed by chrysin, progesterone or allopregnanolone, respectively. After the treatments, the rats underwent the behavioral tests. RESULTS: Chrysin, progesterone, and allopregnanolone increased the latency to the first immobility and decreased the total immobility time in the forced swim test. The number of crossings and the time spent rearing and grooming decreased from the pretest to test sessions in the locomotor activity test. Chrysin, progesterone, and allopregnanolone only prevented the decreases in rearing and grooming. Bicuculline blocked the effects of chrysin, progesterone, and allopregnanolone in both behavioral tests. CONCLUSIONS: These results show that the GABA-binding site at GABAA receptors participates in the acute antidepressant-like effects of chrysin, similar to neurosteroids, in ovariectomized rats.
Asunto(s)
Depresión/fisiopatología , Flavonoides/farmacología , Neuronas GABAérgicas/metabolismo , Animales , Antidepresivos/farmacología , Bicuculina/farmacología , Depresión/tratamiento farmacológico , Femenino , Flavonoides/metabolismo , Neuronas GABAérgicas/efectos de los fármacos , Neuronas GABAérgicas/fisiología , Locomoción/efectos de los fármacos , Neuroesteroides , Ovariectomía , Pregnanolona/farmacología , Progesterona/farmacología , Ratas , Ratas Wistar , Receptores de GABA-A/efectos de los fármacosRESUMEN
Abstract Natural compounds from marine organisms have been rarely studied for their acetylcholinesterase inhibitory activities. The aim of this study was to isolate novel compounds with antiAChE activity from the venom of upside-down jellyfish Cassiopea andromeda Forskål, 1775. The compounds of the fractionated venom on gel filtration chromatography were identified by analyzing gas chromatography-mass spectroscopy data. The structure of the isolated compound that showed the most potent antiAChE activity in a docking study was elucidated by different spectral data, including 1H NMR and 13C NMR. Three compounds, including a neurosteroidal alkaloid androtoxin B, were identified from two venom fractions. This neurosteroidal alkaloid showed strong acetylcholinesterase inhibitory activity (IC50 2.24 ± 0.1 µM) compared with the reference standard, galantamine. The results obtained by a docking study demonstrated that Androtoxin B had close contact with two of the three amino acid residues of the catalytic triad of acetylcholinesterase gorge and was accommodated within a peripheral hydrophobic pocket composed of numerous aromatic site chains. In conclusion, the isolated neurosteroidal alkaloid from Cassiopea andromeda was a potent antiAChE agent with strong binding to both the catalytic and peripheral sites of acetylcholinesterase that correlated well with the experimental data. Further studies are required to determine whether androtoxin B could be a potential treatment for Alzheimer's disease.
RESUMEN
The synthesis, in vitro ligand binding study and in vivo Elevated Plus Maze test (EPM) of a series of pyrazolo[4,3-c]quinolin-3-ones (PQs) are reported. Multistep synthesis of PQs started from anilines and diethyl 2-(ethoxymethylene)malonate to give the quinolin-4-one nucleus, via the Gould-Jacobs reaction. These quinolinones were transformed to 4-chloroquinolines, which react with aryl-hydrazines affording the final compounds. PQs exhibited different potency in displacing specific [3H]Flunitrazepam binding from the benzodiazepine binding site at the γ-aminobutyric acid receptor (GABAA-R) depending on the substitution of the pyrazoloquinolone nucleus. PCA helped determine how different substituents contributed to the differential behavior of the PQs studied. Compounds with high affinity for the GABAA-R were tested regarding their anxiolytic properties in Wistar adult male rats using the Elevated Plus Maze (EPM). Thus, PQs with a p-methoxy phenyl group at N-1 (7b-ii and 7c-ii) displayed a remarkable anxiolytic activity at low doses (0.5-1.0â¯mg/kg). Meanwhile, PQs featuring an unsubstituted phenyl (7b-i) or p-fluoro phenyl group (7b-iii) at the N-1 showed anxiogenic effects in the EPM test.
Asunto(s)
Ansiolíticos/farmacología , Ansiedad/tratamiento farmacológico , Conducta Animal/efectos de los fármacos , Aprendizaje por Laberinto/efectos de los fármacos , Quinolonas/farmacología , Receptores de GABA-A/metabolismo , Animales , Ansiolíticos/síntesis química , Ansiolíticos/química , Relación Dosis-Respuesta a Droga , Ligandos , Masculino , Estructura Molecular , Quinolonas/síntesis química , Quinolonas/química , Ratas , Ratas Wistar , Relación Estructura-ActividadRESUMEN
Malaria, parasitic disease considered a major health public problem, is caused by Plasmodium protozoan genus and transmitted by the bite of infected female Anopheles mosquito genus. Cerebral malaria (CM) is the most severe presentation of malaria, caused by P. falciparum and responsible for high mortality and enduring development of cognitive deficits which may persist even after cure and cessation of therapy. In the present study we evaluated selected behavioral, neurochemical and neuropathologic parameters after rescue from experimental cerebral malaria caused by P. berghei ANKA in C57BL/6 mice. Behavioral tests showed impaired nest building activity as well as increased marble burying, indicating that natural behavior of mice remains altered even after cure of infection. Regarding the neurochemical data, we found decreased α2/α3 Na+,K+-ATPase activity and increased immunoreactivity of phosphorylated Na+,K+-ATPase at Ser943 in cerebral cortex after CM. In addition, [3H]-Flunitrazepam binding assays revealed a decrease of benzodiazepine/GABAA receptor binding sites in infected animals. Moreover, in hippocampus, dot blot analysis revealed increased levels of protein carbonyls, suggesting occurrence of oxidative damage to proteins. Interestingly, no changes in the neuropathological markers Fluoro-Jade C, Timm staining or IBA-1 were detected. Altogether, present data indicate that behavioral and neurochemical alterations persist even after parasitemia clearance and CM recovery, which agrees with available clinical findings. Some of the molecular mechanisms reported in the present study may underlie the behavioral changes and increased seizure susceptibility that persist after recovery from CM and may help in the future development of therapeutic strategies for CM sequelae.
Asunto(s)
Conducta Animal , Malaria Cerebral/metabolismo , Malaria Cerebral/psicología , Plasmodium berghei/patogenicidad , Animales , Proteínas de Unión al Calcio/metabolismo , Corteza Cerebral/metabolismo , Femenino , Flunitrazepam/metabolismo , Fluoresceínas/metabolismo , Hipocampo/metabolismo , Malaria Cerebral/parasitología , Malaria Cerebral/patología , Ratones , Proteínas de Microfilamentos/metabolismo , Carbonilación Proteica , Ensayo de Unión Radioligante , Receptores de GABA-A/metabolismo , Compuestos de Plata/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/inmunología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Tritio/metabolismoRESUMEN
AIMS: Various investigations have demonstrated the protective capacity of general anesthetics as neuroprotective agents. The effects of propofol against ischemia are known to reside in its antioxidant properties and its GABAergic activity. Other aromatic alcohols have also been reported as able to protect neurons against oxidative damage. The aim of this work is to evaluate the potential neuroprotective effect of some phenols, structurally analogues of propofol, with proven GABAergic activity. These phenols include the naturally occurring compounds thymol, carvacrol and eugenol, the synthetic product chlorothymol, and the most widely used intravenous anesthetic, propofol, as a reference compound. MATERIALS AND METHODS: Taking primary cultures of cortical neurons as a suitable model to evaluate cellular protection against oxidative damage, we developed an injury model to test potential neuroprotective activity. The intracellular hydroperoxides were also determined. KEY FINDINGS: The results showed that no compound decreased cell viability at concentrations where they were active on the GABAA receptor. In neuroprotection tests, some phenols and Vit E showed a partial protective effect against the oxidative injury. These compounds induced a clear tendency to reduce H2O2 damage, comparing production of hydroperoxides, although these last changes were statistically non-significant. SIGNIFICANCE: Testing the intracellular oxidation levels suggests that this partial protection exerted by propofol, thymol and chlorothymol may be mediated in some way by their antioxidant activities. However, this neuroprotection is not completely correlated with the antioxidant capacity, but it approaches their relative pharmacological potency, which could be interpreted as a final effect that would involve both activities.
Asunto(s)
Anestésicos Intravenosos/farmacología , Antioxidantes/farmacología , Corteza Cerebral/metabolismo , Eugenol/farmacología , Monoterpenos/farmacología , Neuronas/metabolismo , Fármacos Neuroprotectores/farmacología , Timol/farmacología , Animales , Células Cultivadas , Corteza Cerebral/citología , Cimenos , Neuronas/citología , Ratas , Ratas Wistar , Receptores de GABA-A/metabolismoRESUMEN
The effects of cannabinoids in brain areas expressing cannabinoid receptors, such as hypothalamic nuclei, are not yet well known. Several studies have demonstrated the role of hypothalamic nuclei in the organisation of behavioural responses induced through innate fear and panic attacks. Panic-prone states are experimentally induced in laboratory animals through a reduction in the GABAergic activity. The aim of the present study was to examine panic-like elaborated defensive behaviour evoked by GABAA receptor blockade with bicuculline (BIC) in the dorsomedial division of the ventromedial hypothalamus (VMHdm). We also aimed to characterise the involvement of endocannabinoids and the CB1 cannabinoid receptor in the modulation of elaborated defence behavioural responses organised with the VMHdm. The guide-cannula was stereotaxicaly implanted in VMHdm and the animals were treated with anandamide (AEA) at different doses, and the effective dose was used after the pre-treatment with the CB1 receptor antagonist AM251, followed by GABAA receptor blockade in VMHdm. The results showed that the intra-hypothalamic administration of AEA at an intermediate dose (5 pmol) attenuated defence responses induced through the intra-VMHdm microinjection of bicuculline (40 ng). This effect, however, was inhibited when applied central microinjection of the CB1 receptor antagonist AM251 in the VMHdm. Moreover, AM251 potentiates de non-oriented escape induced by bicuculline, effect blocked by pre-treatment with the TRPV1 channel antagonist 6-I-CPS. These results indicate that AEA modulates the pro-aversive effects of intra-VMHdm-bicuculline treatment, recruiting CB1 cannabinoid receptors and the TRPV1 channel is involved in the AM251-related potentiation of bicuculline effects on non-oriented escape behaviour.
Asunto(s)
Reacción de Fuga/fisiología , Receptor Cannabinoide CB1/fisiología , Receptores de GABA-A/fisiología , Canales Catiónicos TRPV/fisiología , Núcleo Hipotalámico Ventromedial/fisiología , Animales , Ácidos Araquidónicos/administración & dosificación , Bicuculina/administración & dosificación , Modelos Animales de Enfermedad , Endocannabinoides/administración & dosificación , Reacción de Fuga/efectos de los fármacos , Antagonistas de Receptores de GABA-A/administración & dosificación , Masculino , Trastorno de Pánico/inducido químicamente , Trastorno de Pánico/fisiopatología , Piperidinas/administración & dosificación , Alcamidas Poliinsaturadas/administración & dosificación , Pirazoles/administración & dosificación , Ratas , Ratas Wistar , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB1/antagonistas & inhibidores , Núcleo Hipotalámico Ventromedial/efectos de los fármacosRESUMEN
OBJECTIVES: (-)-Myrtenol is a natural fragrance monoterpenoid structurally related to α-pinene found in diverse plant essential oils. This study was aimed to assess the anti-ulcerogenic potential of (-)-myrtenol against ethanol-induced gastric lesions and to elucidate the underlying mechanism(s). METHODS: Gastroprotective activity of (-)-myrtenol was evaluated using the mouse model of ethanol-induced gastric damage. To elucidate the gastroprotective mechanism(s), the roles of GABA, prostaglandins, nitric oxide and KATP channels were assessed. Besides, the oxidative stress-related parameters and the mucus content in gastric tissues were analysed. KEY FINDINGS: (-)-Myrtenol at oral doses of 25, 50 and 100 mg/kg significantly decreased the severity of ethanol-induced gastric lesions affording gastroprotection that was accompanied by a decrease in the activity of myeloperoxidase and malondialdehyde, an increase in GPx, SOD, and catalase activity in gastric tissues, and with well-maintained normal levels of nitrite/nitrate, gastric mucus and NP-SHs. Pretreatment with GABA-A receptor antagonist flumazenil, the COX inhibitor indomethacin, and NO synthesis inhibitor L-NAME but not with KATP channel blocker glibenclamide significantly blocked the (-)-myrtenol gastroprotection. CONCLUSION: These results provide first-time evidence for the gastroprotective effect of (-)-myrtenol that could be related to GABAA -receptor activation and antioxidant activity.
Asunto(s)
Antiulcerosos/farmacología , Antioxidantes/farmacología , Monoterpenos/farmacología , Fitoterapia , Receptores de GABA-A/metabolismo , Úlcera Gástrica/metabolismo , Estómago/efectos de los fármacos , Animales , Antiulcerosos/uso terapéutico , Antioxidantes/metabolismo , Antioxidantes/uso terapéutico , Monoterpenos Bicíclicos , Mucosa Gástrica/metabolismo , Masculino , Ratones , Monoterpenos/uso terapéutico , Moco/metabolismo , Myrtus/química , Aceites Volátiles/química , Peroxidasa/metabolismo , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Estómago/patología , Úlcera Gástrica/prevención & control , Ácido gamma-Aminobutírico/metabolismoRESUMEN
The cyclic ketones, thujone and dihydrocarvone, are lipophilic components of essential oils extracted from different plants, which have proven insecticidal activity. The GABAA receptor is activated by the neurotransmitter GABA and is the action site of widely used neurotoxic pesticides. Many compounds that regulate GABAA receptor function interact with membrane lipids, causing changes in their physical properties and consequently, in the membrane dynamic characteristics that modulate receptor macromolecules. In the present study, the biophysical effects of thujone (a gabaergic reference compound) and dihydrocarvone (structurally very similar) were explored by using monomolecular films of DPPC as a model membrane system, to gain insight into membrane-drug interaction. The compression isotherms showed that both ketones expand the DPPC isotherms and increase membrane elasticity. They penetrate the monolayer but their permanence depends on the possibility of establishing molecular interactions with the film component, favored by defects present in the membrane at the phase transition. Finally, by using Brewster angle microscopy (BAM) as a complementary technique for direct visualization of the study films, we found that incorporating ketone seems to reduce molecular repulsion among phospholipid headgroups. Our results reinforce the notion that changes in membrane mechanics may be occurring in the presence of the assayed ketones, suggesting that their interaction with the receptor's surrounding membrane may modulate or affect its functionality, possibly as part of the mechanism of the bioactivity described for thujone and DHC.
Asunto(s)
Membrana Celular/química , Membrana Celular/efectos de los fármacos , Monoterpenos/farmacología , 1,2-Dipalmitoilfosfatidilcolina/química , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Adsorción , Monoterpenos Bicíclicos , Membrana Celular/metabolismo , Monoterpenos Ciclohexánicos , Monoterpenos/química , ReologíaRESUMEN
Argentina Biomedical Science has been historically strong. The development of Human and Veterinary Pharmacology in our country as a pivotal discipline has been acknowledged worldwide because of the quality of its contributions. Argentinean Society of Experimental Pharmacology (SAFE) is a non- profit association whose research fields include Experimental and Clinical Pharmacology. SAFE main goals are described as follow (a) To meet active researchers for studying concerns regarding Experimental and Clinical Pharmacology (b) To launch an initiative for development of the discipline in mainly our country and other collaborative countries worldwide (c) To spread the pharmacological know-how obtained from different research teams (d) To strengthen relations between pharmacologists (e) To facilitate the presentation and discussion of scientific papers. This current article shows the SAFE's more important scientific contribution to pharmacology through its former research scientists to the present.
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Farmacología/historia , Sociedades Científicas/historia , Animales , Investigación Biomédica , Historia del Siglo XX , Historia del Siglo XXI , HumanosRESUMEN
The clinical use of benzodiazepines is limited by the development of tolerance to their pharmacological effects. Tolerance to each of the pharmacological actions of benzodiazepines develops at different rates. The aim of this work was to investigate the mechanism of tolerance by performing behavioral tests in combination with biochemical studies. To this end, we administered prolonged treatments of diazepam to rats for 7 or 14 days. Tolerance to the sedative effects of diazepam was detected by means of the open field test after the 7- and 14-day treatments, whereas tolerance to the anxiolytic actions of benzodiazepine manifested following only the 14-day treatment in the elevated plus maze. The cerebral cortical concentrations of diazepam did not decline after the diazepam treatments, indicating that tolerance was not due to alterations in pharmacokinetic factors. The uncoupling of GABA/benzodiazepine site interactions and an increase in the degree of phosphorylation of the GABAA receptor γ2 subunit at serine 327 in the cerebral cortex were produced by day 7 of diazepam treatment and persisted after 14 days of exposure to benzodiazepine. Thus, these alterations could be part of the mechanism of tolerance to the sedative effects of diazepam. An increase in the percentage of α1-containing GABAA receptors in the cerebral cortex was observed following the 14-day treatment with diazepam but not the 7-day treatment, suggesting that tolerance to the anxiolytic effects is associated with a change in receptor subunit composition. The understanding of the molecular bases of tolerance could be important for the development of new drugs that maintain their efficacies over long-term treatments.
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Ansiolíticos/farmacología , Corteza Cerebral/efectos de los fármacos , Diazepam/farmacología , Tolerancia a Medicamentos/fisiología , Regulación de la Expresión Génica/efectos de los fármacos , Receptores de GABA-A/metabolismo , Animales , Ansiolíticos/metabolismo , Benzodiazepinas/farmacología , Sitios de Unión/efectos de los fármacos , Corteza Cerebral/metabolismo , Diazepam/metabolismo , Esquema de Medicación , Inmunoprecipitación , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Unión Proteica/efectos de los fármacos , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de GABA-A/genética , Factores de Tiempo , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
Neuroactive steroids, like allopregnanolone (A) and pregnanolone (P), bind to specifics sites on the GABAA receptor complex and modulate receptor function. They are capable to inhibit or stimulate the binding of GABAA receptor-specific ligands, like t-butyl-bicyclophosphorothionate, flunitrazepam and muscimol. We have previously characterized a set of oxygen-bridged synthetic steroids (SS) analogs to A or P using synaptosomes. Considering that the subunit composition of the GABAA receptor throughout the central nervous system affects the magnitude of the modulation of the GABAA receptor by NAS, we evaluated the action of two selected SS, in brain sections containing the cerebral cortex (CC) and hippocampus (HC) using quantitative receptor autoradiography. Both SS affected the binding of the three ligands in a similar way to A and P, with some differences on certain CC layers according to the ligand used. One of the SS, the 3α-hydroxy-6,19-epoxypregn-4-ene-20-one (compound 5), behaved similarly to the natural neuroactive steroids. However, significant differences with compound 5 were observed on the HC CA2 region, making it steroid suitable for a specific action. Those differences may be related to structural conformation of the SS and the subunits' composition present on the receptor complex.
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Corteza Cerebral/metabolismo , Hipocampo/metabolismo , Pregnanolona/análogos & derivados , Receptores de GABA-A/metabolismo , Animales , Autorradiografía , Unión Competitiva , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/metabolismo , Corteza Cerebral/efectos de los fármacos , Flunitrazepam/metabolismo , Agonistas de Receptores de GABA-A/metabolismo , Agonistas de Receptores de GABA-A/farmacología , Hipocampo/efectos de los fármacos , Masculino , Muscimol/metabolismo , Pregnanolona/química , Pregnanolona/metabolismo , Pregnanolona/farmacología , Unión Proteica , Ratas Sprague-Dawley , Radioisótopos de Azufre , TritioRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Montanoa tomentosa also named Cihuapatli is a native plant of Mexico that has been used in traditional medicine for the last five centuries mainly as a remedy for reproductive impairments. However, there are reports indicating that this plant was also consumed by Mexican ancient people for its relaxing properties. In order to corroborate this information, the present study was conducted to evaluate the effect of Montanoa tomentosa lyophilisate (MT) on rat׳s anxiety-like behavior and to analyze its mechanism of action. MATERIALS AND METHODS: The anxiolytic-like action of MT (1.5, 3.0, 6.0 and 12.0 mg/kg) was investigated in male Wistar rats tested in three animal models of anxiety: the burying behavior, the elevated plus maze and the hole-board tests. As a positive control, the anti-anxiety effects of different doses of the selective GABAA receptor agonist muscimol were also analyzed. In order to evaluate the participation of the GABAA and oxytocin receptors in the anxiolytic-like actions of MT, the GABAA receptors blockers picrotoxin (0.25 and 0.50 mg/kg), bicuculline (2.0 mg/kg) and flumazenil (5.00 and 10.0 mg/kg), the neurosteroid inhibitor finasteride (50.0 and 100 mg/kg) and the oxytocin receptor antagonist atosiban (0.25 µg) were used. Finally, to evaluate general activity, and motor coordination, the open field and rota-rod tests were used. RESULTS: MT at 3.0 mg/kg showed anxiolytic-like effects in the three anxiety paradigms without affecting reactivity, general motor activity or motor coordination; however, at higher doses sedative effects were observed. Picrotoxin (0.25 and 0.50 mg/kg), flumazenil (10.0 mg/kg) and finasteride (100 mg/kg) antagonized the anxiolytic-like actions of MT in the burying behavior test. In the plus maze and hole-board tests bicuculline (2.0 mg/kg) blocked the effects of the plant as well. Atosiban (0.25 µg) did not antagonize the anxiolytic-like actions of MT. CONCLUSIONS: The results corroborate the anxiolytic-like actions of Montanoa tomentosa and suggest that this effect is mediated through GABAA receptors but not oxytocin receptors.
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Ansiolíticos/farmacología , Ansiedad/tratamiento farmacológico , Montanoa/química , Extractos Vegetales/farmacología , Receptores de GABA-A/metabolismo , Animales , Ansiolíticos/química , Conducta Animal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica , Masculino , Muscimol/administración & dosificación , Muscimol/farmacología , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Ratas , Ratas Wistar , Receptores de GABA-A/genéticaRESUMEN
Ghrelin (Grh) is an endogenous ligand of the growth hormone secretagogue receptor. In neonatal chicks, central Ghr induces anxiogenic-like behavior but strongly inhibits food intake. The intermediate medial mesopallium (IMM) of the chick forebrain has been identified to be a site of the memory formation, and the modulation of the GABAA receptors that are present here modifies the expression of behavior. Thus, the GABAergic system may constitute a central pathway for Ghr action in regulating the processes of food intake and stress-related behaviors. Therefore, we investigated if the effect of systemic administration of bicuculline (GABAA receptor antagonist) and diazepam (benzodiazepine receptor agonist) on the anxiety in an Open Field test and inhibition in food intake induced by Grh (30pmol) when injected into IMM, were mediated by GABAergic transmission. In Open Field test, bicuculline was able to block the anxiogenic-like behavior induced by Ghr, whereas diazepam did not produce it. However, the co-administration of bicuculline or diazepam plus Ghr did not show any change in food intake at 30, 60 and 120min after injection compared to Ghr alone. Our results indicate for the first time that Ghr, injected into the forebrain IMM area, induces an anxiogenic-like behavior, which was blocked by bicuculline but not diazepam, thus suggesting that Ghr plays an important role in the response pattern to acute stressor, involving the possible participation of the GABAergic system. Nevertheless, as neither drug affected the hypophagia induced by intra-IMM Ghr, this suggests that it may be mediated by different mechanisms.
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Ansiedad/metabolismo , Conducta Animal/fisiología , Cerebro/metabolismo , Ingestión de Alimentos/fisiología , Ghrelina/fisiología , Receptores de GABA-A/fisiología , Animales , Animales Recién Nacidos , Ansiedad/inducido químicamente , Conducta Animal/efectos de los fármacos , Cerebro/efectos de los fármacos , Pollos , Ingestión de Alimentos/efectos de los fármacos , Femenino , Ghrelina/administración & dosificación , Ghrelina/farmacología , MasculinoRESUMEN
Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological therapy for the treatment of pain. The present work investigated the effect of cannabidiol, naloxone and diazepam in combination with 10 Hz and 150 Hz TENS. Male Wistar rats were submitted to the tail-flick test (baseline), and each rodent received an acute administration (intraperitoneal) of naloxone (3.0mg/kg), diazepam (1.5mg/kg) or cannabidiol (0.75 mg/kg, 1.5mg/kg, 3.0mg/kg, 4.5mg/kg, 6.0mg/kg and 12.0mg/kg); 10 min after the acute administration, 10 Hz or 150 Hz TENS or a sham procedure was performed for 30 min. Subsequently, tail-flick measures were recorded over a 90-min period, at 5-min intervals. 10 Hz TENS increased the nociceptive threshold during the 90-min period. This antinociceptive effect was reversed by naloxone pre-treatment, was not altered by diazepam pre-treatment and was abolished by cannabidiol pre-treatment (1.5mg/kg). Moreover, 150 Hz TENS increased tail-flick latencies by 35 min post-treatment, which was partially inhibited by naloxone pre-treatment and totally inhibited by cannabidiol (1.5mg/kg). These data suggest the involvement of the endogenous opioid system and the cannabinoid-mediated neuromodulation of the antinociception induced by transcutaneous electrostimulation at 10 Hz and 150 Hz TENS.