Hypericum perforatum chronic treatment affects cognitive parameters and brain neurotrophic factor levels

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.

Anchusa italica extract: phytochemical and neuroprotective evaluation on global cerebral ischemia and reperfusion

Abstract Stroke is the third leading cause of mortality and disability in industrial countries. Treatment with herbs with antioxidant properties has been reported to be an alternative to the conventional treatments. This study was conducted to investigate the effect of Anchusa italica extract on hippocampal injury induced by transient global cerebral ischemia and reperfusion in the rat. To do so, 50 rats were randomly assigned to five groups; control, sham, ischemia, and 50 or 100 mg/kg of Anchusa italica treated animals. Ischemia was induced by occlusion of carotid artery for 30 minutes. Afterward, behavioral tests and biochemical analyses were conducted. Induction of ischemia/reperfusion caused a decline in learning and passive avoidance memory in rats. Moreover, Anchusa italica caused an increase in learning and improved the passive avoidance memory. Induction of ischemia/reperfusion caused a decrease in the antioxidant capacity of the brain and serum as well as an increase in the malondialdehyde of the brain and serum. Anchusa italica led to an increase in the antioxidant capacity of the brain and serum and decrease in the malondialdehyde of the brain and serum. Overall, because of its protective effects on spatial memory, passive avoidance learning, antioxidant capacity, and lipid peroxidation during ischemia/reperfusion, Anchusa italica might be beneficial in ischemic patients.

Scopolamine reduces the density of M1 muscarinic neurons in rats' hippocampus / La escopolamina reduce la densidad de las neuronas muscarínicas M1 en el hipocampo de ratas

Cholinergic system in CNS is involved in learning and memory. Scopolamine as muscarinic acetylcholine receptor antagonist is used for creation of memory impairment. The purpose of this study is evaluation of scopolamine-based amnesia on memory retention and the effect of this phenomenon on the number of neurons contains M1-receptors in the male Wistar rats hippocampal regions. Thirty-five male Wistar rats (200+/-20 g) were distributed randomly into five groups. Control group (intact samples) and 3 experimental groups with sham group (saline) were tested by the method of passive avoidance (shuttle box) in doses of 0.2, 0.5 and 1 mg/kg (intraperitoneally) as a single dose. After one week, memory test was taken from the rats. Finally, brains dissected from sacrificed rats, and then processed tissues were stained with antibody against M1 receptors (Immunohistochemistry technique) followed by counting of hippocampal CA1, CA3 and DG regions. Our results showed significant decrease in neurons contains M1-receptors in all area of hippocampus. We found that the less number of M1-neurons showed in 1 mg/kg dose of scopolamine. We concluded that scopolamine as muscarinic acetylcholine receptor antagonist can reduce dose-dependently the density of M1-neurons in all areas of hippocampus.

El sistema colinérgico en el SNC está implicado en el aprendizaje y la memoria. La escopolamina como receptor antagonista de acetilcolina muscarínico es utilizada para la creación del deterioro de la memoria. El propósito de este estudio es la evaluación de la amnesia basada en escopolamina sobre la retención de memoria y el efecto de este fenómeno en la cantidad de neuronas en receptores M1 en regiones del hipocampo en ratas macho Wistar. Se distribuyeron al azar, 35 ratas macho Wistar (200+/-20 g) en cinco grupos. El grupo de control (muestras intactas) y 3 grupos experimentales con grupo de tratamiento simulado (solución salina) analizadas por método de evasión pasiva (caja de transporte) en dosis de 0,2; 0,5 y 1 mg/kg (por vía intraperitoneal) como dosis única. Al término de una semana se realizó prueba de memoria de las ratas. Por último, los cerebros diseccionados de las ratas sacrificadas y los tejidos procesados fueron teñidos con anticuerpos contra los receptores M1 (técnica inmunohistoquímica), seguido por el recuento de regiones CA1, CA3 y DG del hipocampo. Nuestros resultados mostraron una disminución significativa en las neuronas con receptores M1 en toda el área del hipocampo. Se encontró que el número menor de neuronas M1, y fue demostrado en 1 mg/kg de dosis de escopolamina. Llegamos a la conclusión de que la escopolamina como antagonista del receptor de acetilcolina muscarínico puede, dependiendo de la dosis, reducir la densidad de neuronas M1 en todas las áreas del hipocampo.