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1.
Braz. J. Psychiatry (São Paulo, 1999, Impr.) ; 40(4): 367-375, Oct.-Dec. 2018. graf
Artículo en Inglés | LILACS | ID: biblio-959251

RESUMEN

Objective: To evaluate the effects of Hypericum perforatum (hypericum) on cognitive behavior and neurotrophic factor levels in the brain of male and female rats. Methods: Male and female Wistar rats were treated with hypericum or water during 28 days by gavage. The animals were then subjected to the open-field test, novel object recognition and step-down inhibitory avoidance test. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial cell-line derived neurotrophic factor (GDNF) levels were evaluated in the hippocampus and frontal cortex. Results: Hypericum impaired the acquisition of short- and long-term aversive memory in male rats, evaluated in the inhibitory avoidance test. Female rats had no immediate memory acquisition and decreased short-term memory acquisition in the inhibitory avoidance test. Hypericum also decreased the recognition index of male rats in the object recognition test. Female rats did not recognize the new object in either the short-term or the long-term memory tasks. Hypericum decreased BDNF in the hippocampus of male and female rats. Hypericum also decreased NGF in the hippocampus of female rats. Conclusions: The long-term administration of hypericum appears to cause significant cognitive impairment in rats, possibly through a reduction in the levels of neurotrophic factors. This effect was more expressive in females than in males.


Asunto(s)
Animales , Masculino , Femenino , Extractos Vegetales/farmacología , Cognición/efectos de los fármacos , Hypericum , Lóbulo Frontal/metabolismo , Hipocampo/metabolismo , Factores de Crecimiento Nervioso/análisis , Extractos Vegetales/administración & dosificación , Distribución Aleatoria , Factores Sexuales , Resultado del Tratamiento , Ratas Wistar , Modelos Animales , Patrones de Reconocimiento Fisiológico/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Lóbulo Frontal/efectos de los fármacos , Hipocampo/efectos de los fármacos , Locomoción/efectos de los fármacos , Memoria/efectos de los fármacos , Factores de Crecimiento Nervioso/efectos de los fármacos
2.
Braz J Psychiatry ; 40(4): 367-375, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30110089

RESUMEN

OBJECTIVE: To evaluate the effects of Hypericum perforatum (hypericum) on cognitive behavior and neurotrophic factor levels in the brain of male and female rats. METHODS: Male and female Wistar rats were treated with hypericum or water during 28 days by gavage. The animals were then subjected to the open-field test, novel object recognition and step-down inhibitory avoidance test. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial cell-line derived neurotrophic factor (GDNF) levels were evaluated in the hippocampus and frontal cortex. RESULTS: Hypericum impaired the acquisition of short- and long-term aversive memory in male rats, evaluated in the inhibitory avoidance test. Female rats had no immediate memory acquisition and decreased short-term memory acquisition in the inhibitory avoidance test. Hypericum also decreased the recognition index of male rats in the object recognition test. Female rats did not recognize the new object in either the short-term or the long-term memory tasks. Hypericum decreased BDNF in the hippocampus of male and female rats. Hypericum also decreased NGF in the hippocampus of female rats. CONCLUSIONS: The long-term administration of hypericum appears to cause significant cognitive impairment in rats, possibly through a reduction in the levels of neurotrophic factors. This effect was more expressive in females than in males.


Asunto(s)
Cognición/efectos de los fármacos , Lóbulo Frontal/metabolismo , Hipocampo/metabolismo , Hypericum , Factores de Crecimiento Nervioso/análisis , Extractos Vegetales/farmacología , Animales , Relación Dosis-Respuesta a Droga , Femenino , Lóbulo Frontal/efectos de los fármacos , Hipocampo/efectos de los fármacos , Locomoción/efectos de los fármacos , Masculino , Memoria/efectos de los fármacos , Modelos Animales , Factores de Crecimiento Nervioso/efectos de los fármacos , Patrones de Reconocimiento Fisiológico/efectos de los fármacos , Extractos Vegetales/administración & dosificación , Distribución Aleatoria , Ratas Wistar , Factores Sexuales , Resultado del Tratamiento
3.
Eur J Neurosci ; 46(2): 1779-1789, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28544049

RESUMEN

Learning to associate a stimulus with reinforcement causes plasticity in primary sensory cortex. Neural activity caused by the associated stimulus is paired with reinforcement, but population analyses have not found a selective increase in response to that stimulus. Responses to other stimuli increase as much as, or more than, responses to the associated stimulus. Here, we applied population analysis at a new time point and additionally evaluated whether cholinergic receptor blockers interacted with the plastic changes in cortex. Three days of tone identification behavior caused responsiveness to increase broadly across primary auditory cortex, and target responses strengthened less than overall responsiveness. In pharmacology studies, behaviorally impairing doses of selective acetylcholine receptor blockers were administered during behavior. Neural responses were evaluated on the following day, while the blockers were absent. The muscarinic group, blocked by scopolamine, showed lower responsiveness and an increased response to the tone identification target that exceeded both the 3-day control group and task-naïve controls. Also, a selective increase in the late phase of the response to the tone identification stimulus emerged. Nicotinic receptor antagonism, with mecamylamine, more modestly lowered responses the following day and lowered target responses more than overall responses. Control acute studies demonstrated the muscarinic block did not acutely alter response rates, but the nicotinic block did. These results lead to the hypothesis that the decrease in the proportion of the population spiking response that is selective for the target may be explained by the balance between effects modulated by muscarinic and nicotinic receptors.


Asunto(s)
Corteza Auditiva/metabolismo , Percepción Auditiva/fisiología , Neuronas/metabolismo , Patrones de Reconocimiento Fisiológico/fisiología , Receptores Muscarínicos/metabolismo , Receptores Nicotínicos/metabolismo , Estimulación Acústica , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Corteza Auditiva/efectos de los fármacos , Percepción Auditiva/efectos de los fármacos , Mapeo Encefálico , Condicionamiento Operante/efectos de los fármacos , Condicionamiento Operante/fisiología , Masculino , Mecamilamina/farmacología , Microelectrodos , Antagonistas Muscarínicos/farmacología , Neuronas/efectos de los fármacos , Antagonistas Nicotínicos/farmacología , Patrones de Reconocimiento Fisiológico/efectos de los fármacos , Ratas Sprague-Dawley , Escopolamina/farmacología
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