Neuroprotective effects of Bacopa monnieri (Brahmi) on novel object recognition and NMDAR1 immunodensity in the prefrontal cortex, striatum and hippocampus of sub-chronic phencyclidine rat model of schizophrenia.
Cognitive impairment is a major problem, which eventually develops in schizophrenia. It contributes to the patients functional disability and cannot be attenuated by antipsychotic drugs. Bacopa monnieri (Brahmi), a neuroprotective herbal medicine in the elderly, might be a novel neuroprotective agent for prevention of cognitive deficit in schizophrenia. To study neuroprotective effects ofBrahmi on novel object recognition task and cerebral glutamateN-methyl-D- aspartate receptor subtype 1 (NMDAR1) immunodensity in sub-chronic phencyclidine (PCP) rat model ofschizophrenia. Rats were assigned to three groups Group-A Control, Group-B PCP administration and Group- C Brahmi PCP. Discrimination ratio (DR) representing cognitive ability was obtainedfrom novel object recognition task. NMDAR1 immunodensity was measured in prefrontal cortex, striatum, cornu ammonis fields I (CA 1) and 23 (CA23) and dentate gyrus (DG) using immunohistochemistry. DR was significantly reduced in PCP group compared with control. This occurred alongside NMDAR1 up-regulation in CA23 and DG but not in prefrontal cortex, striatum or CA1. Brahmi PCP group showed an increased DR score up to normal which occurred alongside a significantly decreased NMDARI immunodensity in CA23 and DG compared with PCP group. Cognitive deficit observed in rats receiving PCP was mediated by NMDAR1 up-regulation in CA23 and DG Interestingly, receiving Brahmi before PCP administration can restore this cognitive deficit by decreasingNMDAR1 in these brain areas. Therefore, Brahmi could be a novel neuroprotective agentfor the prevention ofcognitive deficit in schizophrenia.