RESUMEN
The Federal Pain Research Strategy recommended development of nonopioid analgesics as a top priority in its strategic plan to address the significant public health crisis and individual burden of chronic pain faced by >100 million Americans. Motivated by this challenge, a natural product extracts library was screened and identified a plant extract that targets activity of voltage-gated calcium channels. This profile is of interest as a potential treatment for neuropathic pain. The active extract derived from the desert lavender plant native to southwestern United States, when subjected to bioassay-guided fractionation, afforded 3 compounds identified as pentacyclic triterpenoids, betulinic acid (BA), oleanolic acid, and ursolic acid. Betulinic acid inhibited depolarization-evoked calcium influx in dorsal root ganglion (DRG) neurons predominantly through targeting low-voltage-gated (Cav3 or T-type) and CaV2.2 (N-type) calcium channels. Voltage-clamp electrophysiology experiments revealed a reduction of Ca, but not Na, currents in sensory neurons after BA exposure. Betulinic acid inhibited spontaneous excitatory postsynaptic currents and depolarization-evoked release of calcitonin gene-related peptide from lumbar spinal cord slices. Notably, BA did not engage human mu, delta, or kappa opioid receptors. Intrathecal administration of BA reversed mechanical allodynia in rat models of chemotherapy-induced peripheral neuropathy and HIV-associated peripheral sensory neuropathy as well as a mouse model of partial sciatic nerve ligation without effects on locomotion. The broad-spectrum biological and medicinal properties reported, including anti-HIV and anticancer activities of BA and its derivatives, position this plant-derived small molecule natural product as a potential nonopioid therapy for management of chronic pain.
Asunto(s)
Canales de Calcio Tipo N/metabolismo , Canales de Calcio Tipo T/metabolismo , Infecciones por VIH/complicaciones , Neuralgia/tratamiento farmacológico , Neuralgia/etiología , Paclitaxel/toxicidad , Triterpenos/uso terapéutico , Animales , Antiinflamatorios no Esteroideos/toxicidad , Células CHO , Cricetulus , Diprenorfina/farmacocinética , Modelos Animales de Enfermedad , Femenino , Ganglios Espinales/citología , Potenciales Postsinápticos Inhibidores/efectos de los fármacos , Potenciales Postsinápticos Inhibidores/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Triterpenos Pentacíclicos , Traumatismos de los Nervios Periféricos/inducido químicamente , Traumatismos de los Nervios Periféricos/complicaciones , Traumatismos de los Nervios Periféricos/etiología , Traumatismos de los Nervios Periféricos/virología , Ratas , Ratas Sprague-Dawley , Tritio/farmacocinética , Ácido BetulínicoRESUMEN
The neonatal exposure to general anesthetics has been associated with neuronal apoptosis and dendritic spines morphologic changes in the developing brain. Ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, is widely used in pediatric patients to induce general anesthesia, analgesia, and perioperative sedation. In the present study, we investigated short- and long-term effects of a single ketamine (20 mg/kg, s.c.) neonatal exposure at postnatal day 7 in rats on the hippocampal and frontal cortical cellular viability. Additionally, putative neurochemical alterations and neurobehavioral impairments were evaluated in the adulthood. Ketamine neonatal administration selectively decreased cellular viability in the hippocampus, but not in the frontal cortex, 24 h after the treatment. Interestingly, a single ketamine neonatal exposure prevented the vulnerability to glutamate-induced neurotoxicity in the frontal cortex of adult rats. No short- or long-term damage to cellular membranes, as an indicative of cell death, was observed in hippocampal or cortical slices. However, ketamine induced a long-term increase in hippocampal glutamate uptake. Regarding behavioral analysis, neonatal ketamine exposure did not alter locomotor activity and anxiety-related parameters evaluated in the open-field test. However, ketamine administration disrupted the hippocampal-dependent object recognition ability of adult rats, while improved the motor coordination addressed on the rotarod. These findings indicate that a single neonatal ketamine exposure induces a short-term reduction in the hippocampal, but not in cortical, cellular viability, and long-term alterations in hippocampal glutamate transport, improvement on motor performance, and short-term recognition memory impairment.
Asunto(s)
Sistema de Transporte de Aminoácidos X-AG/metabolismo , Conducta Animal/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores/toxicidad , Lóbulo Frontal/metabolismo , Hipocampo/metabolismo , Ketamina/toxicidad , Animales , Animales Recién Nacidos , Conducta Exploratoria/efectos de los fármacos , Femenino , Ácido Glutámico/farmacocinética , Ácido Glutámico/toxicidad , Técnicas In Vitro , Masculino , Ratas , Ratas Wistar , Reconocimiento en Psicología/efectos de los fármacos , Natación , Tritio/farmacocinéticaRESUMEN
The analgesic mechanisms of mu opioid receptor (MOR) agonists, including receptor occupancy at the site of action, are not completely understood. The aims of the present study were to evaluate: (i) receptor occupancy in the rat brain after administration of MOR agonists; (ii) the relationship between occupancy and the antinociceptive effect. Morphine (2 or 4â¯mg/kg) or oxycodone (1 or 3â¯mg/kg) was subcutaneously administered to rats. The antinociceptive effect of these drugs was measured by the hot-plate test. MOR occupancy in the thalamus was assessed by conducting an ex vivo receptor binding assay using [3H] [D-Ala2, N-MePhe4, Gly-ol]-enkephalin, followed by autoradiographic analysis. Both drugs produced antinociception in a dose-dependent manner, and these effects disappeared after the time point at which the maximal effect was elicited. Thalamic MOR occupancy was observed in a dose-dependent manner at the time point at which maximal antinociception was elicited, and relatively low occupancy was observed when the antinociceptive effect was decreasing. Good correlation between thalamic MOR occupancy and the antinociceptive effect was observed. These findings provide direct evidence for the receptor occupancy of MOR agonists at the site of action and its relationship with the analgesic effect.
Asunto(s)
Analgésicos Opioides/farmacología , Nocicepción/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Receptores Opioides mu/metabolismo , Tálamo/efectos de los fármacos , Tálamo/metabolismo , Animales , Autorradiografía , Relación Dosis-Respuesta a Droga , Encefalina Ala(2)-MeFe(4)-Gli(5)/farmacocinética , Masculino , Morfina/farmacología , Oxicodona/farmacología , Dimensión del Dolor , Ratas , Ratas Sprague-Dawley , Tálamo/diagnóstico por imagen , Factores de Tiempo , Tritio/farmacocinéticaRESUMEN
Some volatile aromatic solvents have similar or opposite effects to anesthetics in the central nervous system. Like for anesthetics, the mechanisms of action involved are currently the subject of debate. This paper presents an in vivo study to determine whether direct binding or effects on membrane fluidity best explain how solvents counterbalance anesthesia's depression of the middle-ear reflex (MER). Rats were anesthetized with a mixture of ketamine and xylazine while also exposed to solvent vapors (toluene, ethylbenzene, or one of the three xylene isomers) and the amplitude of their MER was monitored. The depth of anesthesia was standardized based on the magnitude of the contraction of the muscles involved in the MER, determined by measuring cubic distortion product oto-acoustic emissions (DPOAEs) while triggering the bilateral reflex with contralateral acoustic stimulation. The effects of the aromatic solvents were quantified based on variations in the amplitude of the DPOAEs. The amplitude of the alteration to the MER measured in anesthetized rats did not correlate with solvent lipophilocity (as indicated by logKow values). Results obtained with the three xylene isomers indicated that the positions of two methyl groups around the benzene ring played a determinant role in solvent/neuronal cell interaction. Additionally, Solid-state Nuclear Magnetic Resonance (NMR) spectra for brain microsomes confirmed that brain lipid fluidity was unaffected by solvent exposure, even after three days (6h/day) at an extremely high concentration (3000ppm). Therefore, aromatic solvents appear to act directly on the neuroreceptors involved in the acoustic reflex circuit, rather than on membrane fluidity. The affinity of this interaction is determined by stereospecific parameters rather than lipophilocity.
Asunto(s)
Oído Medio/fisiología , Fluidez de la Membrana/efectos de los fármacos , Reflejo Acústico/efectos de los fármacos , Solventes/farmacología , Estimulación Acústica , Animales , Encéfalo/metabolismo , Oído Medio/efectos de los fármacos , Lateralidad Funcional/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Masculino , Fluidez de la Membrana/fisiología , Emisiones Otoacústicas Espontáneas/efectos de los fármacos , Ratas , Reflejo Acústico/fisiología , Solventes/metabolismo , Tolueno/farmacología , Tritio/farmacocinéticaRESUMEN
Triple reuptake inhibitors that block dopamine transporters (DATs), norepinephrine transporters (NETs), and serotonin transporters (SERTs) are being developed as a new class of antidepressants that might have better efficacy and fewer side effects than traditional antidepressants. In this study, we performed in vitro binding and uptake assays as well as in vivo behavioural tests to assess the pharmacological properties and antidepressant-like efficacy of Yuanzhi-1. In vitro, Yuanzhi-1 had a high affinity for SERTs, NETs, and DATs prepared from rat brain tissue (Ki=3.95, 4.52 and 0.87nM, respectively) and recombinant cells (Ki=2.87, 6.86 and 1.03nM, respectively). Moreover, Yuanzhi-1 potently inhibited the uptake of serotonin (5-hydroxytryptamine; 5-HT), norepinephrine (NE) and dopamine (DA) into rat brain synaptosomes (Ki=2.12, 4.85 and 1.08nM, respectively) and recombinant cells (Ki=1.65, 5.32 and 0.68nM, respectively). In vivo, Yuanzhi-1 decreased immobility in a dose-dependent manner, which was shown among rats via the forced-swim test (FST) and mice via the tail-suspension test (TST). The results observed in the behavioural tests did not appear to result from the stimulation of locomotor activity. Repeated Yuanzhi-1 treatment (2.5, 5 or 10mg/kg) significantly reversed depression-like behaviours in chronically stressed rats, including reduced sucrose preference, decreased locomotor activity, and prolonged time to begin eating. Furthermore, in vivo microdialysis studies showed that 5- and 10-mg/kg administrations of Yuanzhi-1 significantly increased the extracellular concentrations of 5-HT, NE and DA in the frontal cortices of freely moving rats. Therefore, Yuanzhi-1 might represent a novel triple reuptake inhibitor and possess antidepressant-like activity.
Asunto(s)
Antidepresivos/farmacología , Medicamentos Herbarios Chinos/farmacología , Inhibidores de la Captación de Neurotransmisores/farmacología , Sinaptosomas/efectos de los fármacos , Animales , Citalopram/farmacocinética , Cuerpo Estriado/citología , Depresión/tratamiento farmacológico , Modelos Animales de Enfermedad , Preferencias Alimentarias/efectos de los fármacos , Lóbulo Frontal/citología , Humanos , Masculino , Ratones , Ratones Endogámicos ICR , Neurotransmisores/farmacocinética , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/metabolismo , Unión Proteica/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Saponinas/farmacología , Saponinas/uso terapéutico , Sacarosa/administración & dosificación , Tritio/farmacocinéticaRESUMEN
Yuanzhi, the dried root of Polygala tenuifolia Willd., is a well-known traditional Chinese medicine used for its sedative, antipsychotic, cognitive improving, neuroprotective, and antidepressant effects. The present study was designed to screen and identify the antidepressant-like effect of six triterpenoid saponin components derived from Yuanzhi (Yuanzhi-1 to Yuanzhi-6) using in vitro radioligand receptor binding assays and in vivo behavioral tests. Yuanzhi-1, -3, -5 and -6 were shown to have antidepressant-like activity in the tail suspension test and forced swim test in mice, with no stimulant effect on locomotor activity. The minimal effective dose of Yuanzhi-1 (2.5 mg/kg) was lower than that of duloxetine (5mg/kg), a serotonin and norepinephrine reuptake inhibitor commonly used in the treatment of depression. Yuanzhi-1 (1 nM) had a high affinity for serotonin, norepinephrine and dopamine transporters. Acute toxicity tests indicated that the LD50 of Yuanzhi-1 (86.5mg/kg) was similar to that of duloxetine (73.2 mg/kg). These findings demonstrate that Yuanzhi-1 has a potential to be a novel triple monoamine reuptake inhibitor of antidepressant-like activity.
Asunto(s)
Antidepresivos/uso terapéutico , Depresión/tratamiento farmacológico , Medicina Tradicional China , Saponinas/uso terapéutico , Animales , Antidepresivos/farmacología , Citalopram/farmacocinética , Cocaína/análogos & derivados , Cocaína/farmacocinética , Modelos Animales de Enfermedad , Femenino , Fluoxetina/análogos & derivados , Fluoxetina/farmacología , Masculino , Proteínas de Transporte de Membrana/metabolismo , Ratones , Ratones Endogámicos ICR , Actividad Motora/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Saponinas/química , Natación/psicología , Tritio/farmacocinéticaRESUMEN
Stress and glucocorticoids alter glutamatergic transmission, and the outcome of stress may range from plasticity enhancing effects to noxious, maladaptive changes. We have previously demonstrated that acute stress rapidly increases glutamate release in prefrontal and frontal cortex via glucocorticoid receptor and accumulation of presynaptic SNARE complex. Here we compared the ex vivo effects of acute stress on glutamate release with those of in vitro application of corticosterone, to analyze whether acute effect of stress on glutamatergic transmission is mediated by local synaptic action of corticosterone. We found that acute stress increases both the readily releasable pool (RRP) of vesicles and depolarization-evoked glutamate release, while application in vitro of corticosterone rapidly increases the RRP, an effect dependent on synaptic receptors for the hormone, but does not induce glutamate release for up to 20 min. These findings indicate that corticosterone mediates the enhancement of glutamate release induced by acute stress, and the rapid non-genomic action of the hormone is necessary but not sufficient for this effect.
Asunto(s)
Corticosterona/metabolismo , Lóbulo Frontal/patología , Neuronas/patología , Terminales Presinápticos/metabolismo , Estrés Psicológico/patología , Análisis de Varianza , Animales , Ácido Aspártico/metabolismo , Corticosterona/farmacología , Relación Dosis-Respuesta a Droga , Electrochoque/efectos adversos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Técnicas In Vitro , Masculino , Neuronas/metabolismo , Terminales Presinápticos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Estrés Psicológico/etiología , Sinapsinas/metabolismo , Vesículas Sinápticas/efectos de los fármacos , Vesículas Sinápticas/metabolismo , Sinaptosomas/metabolismo , Tritio/farmacocinéticaRESUMEN
The aim of this study was to investigate the effect of Withania somnifera (WS) extract, withanolide A (WA), and carbamazepine (CBZ) on cerebellar AMPA receptor function in pilocarpine-induced temporal lobe epilepsy (TLE). In the present study, motor learning deficit was studied by rotarod test, grid walk test, and narrow beam test. Motor learning was significantly impaired in rats with epilepsy. The treatment with WS and WA significantly reversed the motor learning deficit in rats with epilepsy when compared with control rats. There was an increase in glutamate content and IP3 content observed in rats with epilepsy which was reversed in WS- and WA-treated rats with epilepsy. alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor dysfunction was analyzed using radiolabeled AMPA receptor binding assay, AMPA receptor mRNA expression, and immunohistochemistry using anti-AMPA receptor antibody. Our results suggest that there was a decrease in Bmax, mRNA expression, and AMPA receptor expression indicating AMPA receptor dysfunction, which is suggested to have contributed to the motor learning deficit observed in rats with epilepsy. Moreover, treatment with WS and WA resulted in physiological expression of AMPA receptors. There was also alteration in GAD and GLAST expression which supplemented the increase in extracellular glutamate. The treatment with WS and WA reversed the GAD and GLAST expression. These findings suggest that WS and WA regulate AMPA receptor function in the cerebellum of rats with TLE, which has therapeutic application in epilepsy.
Asunto(s)
Anticonvulsivantes/uso terapéutico , Epilepsia del Lóbulo Temporal , Discapacidades para el Aprendizaje/etiología , Fitoterapia , Receptores AMPA/metabolismo , Withania , Witanólidos/uso terapéutico , Animales , Carbamazepina/uso terapéutico , Cerebelo/efectos de los fármacos , Cerebelo/metabolismo , Modelos Animales de Enfermedad , Epilepsia del Lóbulo Temporal/complicaciones , Epilepsia del Lóbulo Temporal/patología , Epilepsia del Lóbulo Temporal/terapia , Transportador 1 de Aminoácidos Excitadores/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Glutamato Descarboxilasa/metabolismo , Ácido Glutámico/metabolismo , Inositol 1,4,5-Trifosfato/metabolismo , Modelos Lineales , Locomoción/efectos de los fármacos , Masculino , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Pilocarpina/toxicidad , Unión Proteica/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptores AMPA/genética , Factores de Tiempo , Tritio/farmacocinética , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/farmacocinéticaRESUMEN
Down syndrome (DS) is associated with neurological complications, including cognitive deficits that lead to impairment in intellectual functioning. Increased GABA-mediated inhibition has been proposed as a mechanism underlying deficient cognition in the Ts65Dn (TS) mouse model of DS. We show that chronic treatment of these mice with RO4938581 (3-bromo-10-(difluoromethyl)-9H-benzo[f]imidazo[1,5-a][1,2,4]triazolo[1,5-d][1,4]diazepine), a selective GABA(A) α5 negative allosteric modulator (NAM), rescued their deficits in spatial learning and memory, hippocampal synaptic plasticity, and adult neurogenesis. We also show that RO4938581 normalized the high density of GABAergic synapse markers in the molecular layer of the hippocampus of TS mice. In addition, RO4938581 treatment suppressed the hyperactivity observed in TS mice without inducing anxiety or altering their motor abilities. These data demonstrate that reducing GABAergic inhibition with RO4938581 can reverse functional and neuromorphological deficits of TS mice by facilitating brain plasticity and support the potential therapeutic use of selective GABA(A) α5 NAMs to treat cognitive dysfunction in DS.
Asunto(s)
Síndrome de Down/complicaciones , Síndrome de Down/patología , Hipocampo/patología , Discapacidades para el Aprendizaje/tratamiento farmacológico , Neuronas/fisiología , Receptores de GABA-A/metabolismo , Estimulación Acústica , Análisis de Varianza , Animales , Benzodiazepinas/farmacología , Benzodiazepinas/uso terapéutico , Biofisica , Proteínas Portadoras/metabolismo , Recuento de Células , Proliferación Celular/efectos de los fármacos , Señales (Psicología) , Modelos Animales de Enfermedad , Síndrome de Down/tratamiento farmacológico , Estimulación Eléctrica , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/genética , Conducta Exploratoria/efectos de los fármacos , Moduladores del GABA/farmacología , Moduladores del GABA/uso terapéutico , Glutamato Descarboxilasa/metabolismo , Hipocampo/efectos de los fármacos , Hipercinesia/tratamiento farmacológico , Hipercinesia/etiología , Imidazoles/farmacología , Imidazoles/uso terapéutico , Antígeno Ki-67 , Discapacidades para el Aprendizaje/etiología , Potenciación a Largo Plazo/efectos de los fármacos , Potenciación a Largo Plazo/genética , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Neurogénesis/efectos de los fármacos , Neurogénesis/genética , Neuronas/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Unión Proteica/genética , Desempeño Psicomotor/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos , Reflejo/efectos de los fármacos , Reflejo/genética , Reflejo de Sobresalto/efectos de los fármacos , Prueba de Desempeño de Rotación con Aceleración Constante , Convulsiones/etiología , Filtrado Sensorial/efectos de los fármacos , Tritio/farmacocinética , Proteínas del Transporte Vesicular de Aminoácidos Inhibidores/metabolismoRESUMEN
Julibroside C1 is a saponin-containing compound isolated from Albizzia julibrissin Durazz. In this study, we investigated the putative anxiolytic effects of Julibroside C1 using the elevated plus maze (EPM) in mice. Julibroside C1 at doses of 0.5 and 1 mg/kg significantly increased the time spent in the open arms and the number of entries into the open arms of the EPM compared to the control group. Moreover, the anxiolytic-like effects of Julibroside C1 (0.5 mg/kg) were blocked by WAY-100635 (5-HT1A receptor antagonist), bicuculline (GABA(A) receptor antagonist), and flumazenil (antagonist of the GABA(A) receptor benzodiazepine site). However, Julibroside C1 did not change locomotor activity or induce myorelaxant effects. We used quantitative receptor autoradiography to investigate the effects of Julibroside C1 on alterations in mouse brain receptors. After acute treatment with Julibroside C1 (0.5 mg/kg), [(3)H]-8-OH-DPAT binding was significantly decreased in the CA1 region of the hippocampus and [(3)H]-flunitrazepam binding was decreased remarkably in the cingulate cortex region. However, [(3)H]-muscimol binding did not show a significant change in any brain region. Taken together, our findings suggest that Julibroside C1 shows anxiolytic-like effects, which might be mediated by the 5-HT1A and GABA(A)-benzodiazepine receptor systems.
Asunto(s)
Albizzia/química , Ansiolíticos/farmacología , Aprendizaje por Laberinto/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Saponinas/farmacología , Triterpenos/farmacología , 8-Hidroxi-2-(di-n-propilamino)tetralin/farmacocinética , Análisis de Varianza , Animales , Autorradiografía , Encéfalo/diagnóstico por imagen , Encéfalo/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Flunitrazepam/farmacocinética , Masculino , Ratones , Ratones Endogámicos ICR , Muscimol/farmacocinética , Preparaciones de Plantas/química , Preparaciones de Plantas/farmacología , Unión Proteica/efectos de los fármacos , Cintigrafía , Saponinas/química , Triterpenos/química , Tritio/farmacocinéticaRESUMEN
Glutamate is the major mediator of excitotoxic neuronal death following cerebral ischemia. Under severe ischemic conditions, glutamate transporters can functionally reverse to release glutamate, thereby inducing further neuronal injury. Hypothermia has been shown to protect neurons from brain ischemia. However, the mechanism(s) involved remain unclear. Therefore, the aim of this study was to investigate the mechanism(s) mediating glutamate release during brain ischemia-reperfusion injury under hypothermic conditions. Neuron/astrocyte co-cultures were exposed to oxygen-glucose deprivation (OGD) at various temperatures for 2h, and cell viability was assayed 12h after reoxygenation. PI and MAP-2 staining demonstrated that hypothermia significantly decreased neuronal injury. Furthermore, [(3)H]-glutamate uptake assays showed that hypothermia protected rat primary cortical cultures against OGD reoxygenation-induced injury. Protein levels of the astrocytic glutamate transporter, GLT-1, which is primarily responsible for the clearance of extracellular glutamate, were also found to be reduced in a temperature-dependent manner. In contrast, expression of GLT-1 in astrocyte-enriched cultures was found to significantly increase following the addition of neuron-conditioned medium maintained at 37 °C, and to a lesser extent with neuron-conditioned medium at 33 °C. In conclusion, the neuroprotective effects of hypothermia against brain ischemia-reperfusion injury involve down-regulation of astrocytic GLT-1, which mediates the reverse transport of glutamate. Moreover, this process may be regulated by molecules secreted by stressed neurons.
Asunto(s)
Regulación hacia Abajo/fisiología , Ácido Glutámico/farmacología , Hipotermia Inducida/métodos , Hipoxia/prevención & control , Neuronas/efectos de los fármacos , Análisis de Varianza , Animales , Astrocitos/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Corteza Cerebral/citología , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Regulación hacia Abajo/efectos de los fármacos , Embrión de Mamíferos , Glucosa/deficiencia , Glucosa/metabolismo , Ácido Glutámico/metabolismo , Oxigenoterapia Hiperbárica/métodos , Proteínas del Tejido Nervioso/metabolismo , Ratas , Tritio/farmacocinéticaRESUMEN
Delineation of key molecules that act epigenetically to transduce diverse stressors into established patterns of disease would facilitate the advent of preventive and disease-modifying therapeutics for a host of neurological disorders. Herein, we demonstrate that selective overexpression of the stress protein heme oxygenase-1 (HO-1) in astrocytes of novel GFAP.HMOX1 transgenic mice results in subcortical oxidative stress and mitochondrial damage/autophagy; diminished neuronal reelin content (males); induction of Nurr1 and Pitx3 with attendant suppression of their targeting miRNAs, 145 and 133b; increased tyrosine hydroxylase and α-synuclein expression with downregulation of the targeting miR-7b of the latter; augmented dopamine and serotonin levels in basal ganglia; reduced D1 receptor binding in nucleus accumbens; axodendritic pathology and altered hippocampal cytoarchitectonics; impaired neurovascular coupling; attenuated prepulse inhibition (males); and hyperkinetic behavior. The GFAP.HMOX1 neurophenotype bears resemblances to human schizophrenia and other neurodevelopmental conditions and implicates glial HO-1 as a prime transducer of inimical (endogenous and environmental) influences on the development of monoaminergic circuitry. Containment of the glial HO-1 response to noxious stimuli at strategic points of the life cycle may afford novel opportunities for the effective management of human neurodevelopmental and neurodegenerative conditions.
Asunto(s)
Astrocitos/metabolismo , Encéfalo/patología , Regulación del Desarrollo de la Expresión Génica/genética , Hemo-Oxigenasa 1/metabolismo , Esquizofrenia/genética , Esquizofrenia/patología , Estimulación Acústica , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos , Astrocitos/ultraestructura , Benzamidas/farmacocinética , Benzazepinas/farmacocinética , Monoaminas Biogénicas/metabolismo , Cromatografía Líquida de Alta Presión , Modelos Animales de Enfermedad , Dopaminérgicos/farmacocinética , Embrión de Mamíferos , Ensayo de Inmunoadsorción Enzimática , Trastornos Neurológicos de la Marcha/etiología , Trastornos Neurológicos de la Marcha/genética , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Hemo-Oxigenasa 1/genética , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Inhibición Psicológica , Flujometría por Láser-Doppler , Ratones , Ratones Transgénicos , MicroARNs/genética , MicroARNs/metabolismo , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Unión Proteica/efectos de los fármacos , Unión Proteica/genética , ARN Mensajero/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Proteína Reelina , Esquizofrenia/fisiopatología , Filtrado Sensorial/genética , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Tritio/farmacocinética , Tirosina 3-Monooxigenasa/genética , Tirosina 3-Monooxigenasa/metabolismo , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismoRESUMEN
Acute and prolonged bone complications associated with radiation and chemotherapy in cancer survivors underscore the importance of establishing a laboratory-based complementary dual-isotope tool to evaluate short- as well as long-term bone remodeling in an in vivo model. To address this need, a liquid scintillation dual-label method was investigated using different scintillation cocktails for quantitative measurement of (3)H-tetracycline ((3)H-TC) and (45)Ca as markers of bone turnover in mice. Individual samples were prepared over a wide range of known (45)Ca/(3)H activity ratios. Results showed that (45)Ca/(3)H activity ratios determined experimentally by the dual-label method were comparable to the known activity ratios (percentage difference â¼2%), but large variations were found in samples with (45)Ca/(3)H activity ratios in range of 2-10 (percentage difference â¼20-30%). Urine and fecal samples from mice administered with both (3)H-TC and (45)Ca were analyzed with the dual-label method. Positive correlations between (3)H and (45)Ca in urine (R=0.93) and feces (R=0.83) indicate that (3)H-TC and (45)Ca can be interchangeably used to monitor longitudinal in vivo skeletal remodeling.
Asunto(s)
Remodelación Ósea/fisiología , Radioisótopos de Calcio/farmacocinética , Radioisótopos de Calcio/orina , Heces/química , Conteo por Cintilación/métodos , Tritio/farmacocinética , Tritio/orina , Animales , Huesos/metabolismo , Tasa de Depuración Metabólica , Ratones , Ratones Endogámicos BALB CRESUMEN
Neuropathic pain is a debilitating condition that is often difficult to treat using conventional pharmacological interventions and the exact mechanisms involved in the establishment and maintenance of this type of chronic pain have yet to be fully elucidated. The present studies examined the effect of chronic nerve injury on µ-opioid receptors and receptor-mediated G-protein activity within the supraspinal brain regions involved in pain processing of mice. Chronic constriction injury (CCI) reduced paw withdrawal latency, which was maximal at 10 days post-injury. [d-Ala2,(N-Me)Phe4,Gly5-OH] enkephalin (DAMGO)-stimulated [(35)S]GTPγS binding was then conducted at this time point in membranes prepared from the rostral ACC (rACC), thalamus and periaqueductal grey (PAG) of CCI and sham-operated mice. Results showed reduced DAMGO-stimulated [(35)S]GTPγS binding in the thalamus and PAG of CCI mice, with no change in the rACC. In thalamus, this reduction was due to decreased maximal stimulation by DAMGO, with no difference in EC(50) values. In PAG, however, DAMGO E(max) values did not significantly differ between groups, possibly due to the small magnitude of the main effect. [(3)H]Naloxone binding in membranes of the thalamus showed no significant differences in B(max) values between CCI and sham-operated mice, indicating that the difference in G-protein activation did not result from differences in µ-opioid receptor levels. These results suggest that CCI induced a region-specific adaptation of µ-opioid receptor-mediated G-protein activity, with apparent desensitization of the µ-opioid receptor in the thalamus and PAG and could have implications for treatment of neuropathic pain.
Asunto(s)
Proteínas de Unión al GTP/metabolismo , Receptores Opioides mu/metabolismo , Ciática/patología , Tálamo/metabolismo , Analgésicos Opioides/farmacología , Animales , Constricción , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas/fisiología , Encefalina Ala(2)-MeFe(4)-Gli(5)/farmacología , Guanosina 5'-O-(3-Tiotrifosfato)/farmacocinética , Hiperalgesia/etiología , Masculino , Ratones , Naloxona/farmacocinética , Antagonistas de Narcóticos/farmacocinética , Umbral del Dolor/fisiología , Unión Proteica/efectos de los fármacos , Ciática/complicaciones , Isótopos de Azufre/farmacocinética , Tálamo/fisiopatología , Factores de Tiempo , Tritio/farmacocinéticaRESUMEN
Clozapine, by virtue of its absence of extrapyramidal side effects and greater efficacy, revolutionized the treatment of schizophrenia, although the mechanisms underlying this exceptional activity remain controversial. Combining an unbiased cheminformatics and physical screening approach, we evaluated clozapine's activity at >2350 distinct molecular targets. Clozapine, and the closely related atypical antipsychotic drug olanzapine, interacted potently with a unique spectrum of molecular targets. This distinct pattern, which was not shared with the typical antipsychotic drug haloperidol, suggested that the serotonergic neuronal system was a key determinant of clozapine's actions. To test this hypothesis, we used pet1(-/-) mice, which are deficient in serotonergic presynaptic markers. We discovered that the antipsychotic-like properties of the atypical antipsychotic drugs clozapine and olanzapine were abolished in a pharmacological model that mimics NMDA-receptor hypofunction in pet1(-/-) mice, whereas haloperidol's efficacy was unaffected. These results show that clozapine's ability to normalize NMDA-receptor hypofunction, which is characteristic of schizophrenia, depends on an intact presynaptic serotonergic neuronal system.
Asunto(s)
Clozapina/farmacología , Neuronas/citología , Terminales Presinápticos/efectos de los fármacos , Antagonistas de la Serotonina/farmacología , Serotonina/metabolismo , Estimulación Acústica/métodos , Potenciales de Acción/efectos de los fármacos , Inhibidores de Captación Adrenérgica/farmacología , Anfetaminas/farmacología , Animales , Antipsicóticos/farmacología , Conducta Animal/efectos de los fármacos , Quinasa de Punto de Control 2 , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Ketanserina/farmacocinética , Lisina/análogos & derivados , Lisina/metabolismo , Ratones , Ratones Noqueados , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Actividad Motora/efectos de los fármacos , N-Metil-3,4-metilenodioxianfetamina/farmacología , Neuronas/efectos de los fármacos , Neuronas/fisiología , Técnicas de Placa-Clamp/métodos , Fenciclidina/farmacología , Unión Proteica/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/deficiencia , Ensayo de Unión Radioligante/métodos , Núcleos del Rafe/citología , Receptor de Serotonina 5-HT1A/metabolismo , Reflejo de Sobresalto/efectos de los fármacos , Reflejo de Sobresalto/fisiología , Conducta Estereotipada/efectos de los fármacos , Tritio/farmacocinética , Triptófano Hidroxilasa/metabolismoRESUMEN
In the present study, the effects of Bacopa monnieri and its active component, bacoside A, on motor deficit and alterations of GABA receptor functional regulation in the cerebellum of epileptic rats were investigated. Scatchard analysis of [(3)H]GABA and [(3)H]bicuculline in the cerebellum of epileptic rats revealed a significant decrease in B(max) compared with control. Real-time polymerase chain reaction amplification of GABA(A) receptor subunits-GABA(Aalpha1), GABA(Aalpha5,) and GABA(Adelta)-was downregulated (P<0.001) in the cerebellum of epileptic rats compared with control rats. Epileptic rats exhibit deficits in radial arm and Y-maze performance. Treatment with B. monnieri and bacoside A reversed these changes to near-control levels. Our results suggest that changes in GABAergic activity, motor learning, and memory deficit are induced by the occurrence of repetitive seizures. Treatment with B. monnieri and bacoside A prevents the occurrence of seizures thereby reducing the impairment of GABAergic activity, motor learning, and memory deficit.
Asunto(s)
Síntomas Conductuales , Cerebelo/efectos de los fármacos , Epilepsia/complicaciones , Epilepsia/patología , Fitoterapia/métodos , Preparaciones de Plantas/uso terapéutico , Receptores de GABA/metabolismo , Saponinas/uso terapéutico , Triterpenos/uso terapéutico , Animales , Anticonvulsivantes/uso terapéutico , Síntomas Conductuales/tratamiento farmacológico , Síntomas Conductuales/etiología , Bicuculina/farmacocinética , Carbamazepina/uso terapéutico , Modelos Animales de Enfermedad , Epilepsia/inducido químicamente , Epilepsia/tratamiento farmacológico , Antagonistas del GABA/farmacocinética , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Pilocarpina , Unión Proteica/efectos de los fármacos , Ratas , Ratas Wistar , Tritio/farmacocinética , Ácido gamma-Aminobutírico/farmacocinéticaRESUMEN
L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID) remains a challenge in Parkinson's disease (PD) drug therapy. In the present study, we examined the effect of L-stepholidine (L-SPD), a known dual dopamine receptor agent, on LID in 6-hydroxydopamine (6-OHDA)-lesioned PD rat model. Daily administration of L-DOPA to PD rats for 22 days induced steady expression of LID, co-administration of L-SPD with L-DOPA significantly ameliorated LID without compromising the therapeutic potency of L-DOPA, indicating that L-SPD attenuated LID development. L-SPD alone elicited stable contralateral rotational behavior without inducing significant dyskinesia. Acute administration of L-SPD to rats with established LID produced significant relief of dyskinesia; this effect was mimicked by D(2) receptor antagonist haloperidol, but blunted by 5-HT(1A) receptor antagonist WAY100635. Furthermore, the mRNA level of 5-HT(1A) decreased significantly on 6-OHDA-lesioned striata, whereas chronic L-SPD treatment restored 5-HT(1A) receptor mRNA level on the lesioned striata. The present data demonstrated that L-SPD elicited antidyskinesia effects via both dopamine (D(2) receptor antagonistic activity) and nondopamine (5-HT(1A) agonistic activity) mechanisms.
Asunto(s)
Antiparkinsonianos/efectos adversos , Antipsicóticos/uso terapéutico , Benzazepinas , Berberina/análogos & derivados , Discinesias/tratamiento farmacológico , Discinesias/etiología , Levodopa/efectos adversos , 8-Hidroxi-2-(di-n-propilamino)tetralin/farmacocinética , Análisis de Varianza , Animales , Benzazepinas/administración & dosificación , Berberina/uso terapéutico , Células CHO , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Cricetinae , Cricetulus , Modelos Animales de Enfermedad , Dopaminérgicos/administración & dosificación , Esquema de Medicación , Interacciones Farmacológicas , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Oxidopamina , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/tratamiento farmacológico , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptor de Serotonina 5-HT1A/genética , Receptor de Serotonina 5-HT1A/metabolismo , Agonistas de Receptores de Serotonina/farmacocinética , Transfección , Tritio/farmacocinéticaRESUMEN
The pharmacological actions of 2,6-di-tert-butyl-4-(3-hydroxy-2-spiropentylpropyl)-phenol (BSPP), a putative presynaptic GABA(B) receptor modulator, were examined in electrically stimulated rat neocortical brain slices preloaded with [3H]-GABA or [3H]-glutamic acid. At 10 mmol/L, BSPP inhibited the release of [3H]-GABA in the presence of baclofen, but not that of [3H]-glutamic acid. This effect was sensitive to the GABA(B) receptor antagonist (+)-(S)-5,5-dimethylmorpholinyl-2-acetic acid (Sch 50911). Alone, BSPP had no effect on the release of [3H]-GABA or [3H]-glutamic acid. It is concluded that BSPP selectively potentiates the action of baclofen at GABA(B) autoreceptors, but not heteroreceptors and may be a useful ligand to discriminate between presynaptic GABA(B) receptor subtypes.
Asunto(s)
Baclofeno/farmacología , Antagonistas de Receptores de GABA-B , Neocórtex/efectos de los fármacos , Fenoles/farmacología , Compuestos de Espiro/farmacología , Animales , Evaluación Preclínica de Medicamentos , Sinergismo Farmacológico , Ácido Glutámico/farmacocinética , Masculino , Morfolinas/farmacología , Neocórtex/metabolismo , Técnicas de Cultivo de Órganos , Fenoles/química , Ratas , Ratas Sprague-Dawley , Receptores de GABA-B/metabolismo , Tritio/farmacocinética , Ácido gamma-Aminobutírico/farmacocinéticaRESUMEN
We have investigated the presence of histamine H(3) receptors (H(3)Rs) on rat thalamic isolated nerve terminals (synaptosomes) and the effect of their activation on glutamate and GABA release. N-alpha-[methyl-(3)H]histamine ([(3)H]-NMHA) bound specifically to synaptosomal membranes with dissociation constant (K(d)) 0.78+/-0.20 nM and maximum binding (B(max)) 141+/-12fmol/mg protein. Inhibition of [(3)H]-NMHA binding by histamine and the H(3)R agonist immepip fit better to a two-site model, whereas for the H(3)R antagonist clobenpropit the best fit was to the one-site model. GTPgammaS (30 microM) decreased [(3)H]-NMHA binding by 55+/-4% and made the histamine inhibition fit better to the one-site model. Immepip (30 nM) induced a modest, but significant increase (113+/-2% of basal) in [(35)S]-GTPgammaS binding to synaptosomal membranes, an effect prevented by clobenpropit (1 microM) and by pre-treatment with pertussis toxin. In thalamus synaptosomes depolarisation-induced, Ca(2+)-dependent glutamate release was inhibited by histamine (1 microM, 25+/-4% inhibition) and immepip (30 nM, 38+/-5% reduction). These effects were reversed by clobenpropit (1microM). Conversely, immepip (up to 1 microM) had no effect on depolarisation-evoked [(3)H]-GABA release. Extracellular synaptic responses were recorded in the thalamus ventrobasal complex by stimulating corticothalamic afferents. H(3)R activation reduced by 38+/-7% the glutamate receptor-mediated field potentials (FPs), but increased the FP2/FP1 ratio (from 0.86+/-0.03 to 1.38+/-0.05) in a paired-pulse paradigm. Taken together, our results confirm the presence of H(3)Rs on thalamic nerve terminals and show that their activation modulates pre-synaptically glutamatergic, but not GABAergic neurotransmission.
Asunto(s)
Ácido Glutámico/metabolismo , Terminales Presinápticos/metabolismo , Receptores Histamínicos H3/fisiología , Tálamo/metabolismo , Ácido gamma-Aminobutírico/metabolismo , 4-Aminopiridina/farmacología , Animales , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Potenciales Evocados/efectos de los fármacos , Potenciales Evocados/efectos de la radiación , Guanosina 5'-O-(3-Tiotrifosfato)/farmacología , Histamina/farmacología , Antagonistas de los Receptores Histamínicos , Imidazoles/farmacología , Técnicas In Vitro , Masculino , Metilhistaminas/farmacocinética , Toxina del Pertussis/farmacología , Terminales Presinápticos/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Ratas , Ratas Wistar , Sinaptosomas/efectos de los fármacos , Sinaptosomas/metabolismo , Tálamo/ultraestructura , Tiourea/análogos & derivados , Tiourea/farmacología , Tritio/metabolismo , Tritio/farmacocinéticaRESUMEN
The in vivo dynamic behavior of ginkgolide B (GB), a terpene lactone constituent of the Ginkgo biloba extracts, in the living animal was visualized by positron emission tomographic (PET) imaging using a GB analogue labeled with the positron emitter (18)F. The in vivo imaging studies, combined with ex vivo dissection experiments, reveal that GB exists in 2 forms in the body: the original GB with its lactone rings closed and a second form with one of the rings open. The original GB in plasma is taken up rapidly by various organs including the liver, the intestine and possibly the stomach. Consequently, in plasma, the proportion of the ionized form of GB increases dramatically with time. Thereafter the ratio between the 2 forms appears to shift slowly towards equilibrium. The results suggest that more attention needs to be focused on in vivo dynamics between the 2 forms of GB.