Cognitive Enhancement Effects of Bacopa monnieri (Brahmi) on Novel Object Recognition and Neuronal Density in the Prefrontal Cortex, Striatum and Hippocampus in Sub-Chronic Phencyclidine Administration Rat Model of Schizophrenia
Thanitsara Wetchateng PhD*, Pritsana Piyabhan PhD*
Affiliation : * Department of Preclinical Science, Faculty of Medicine, Thammasat University, Rangsit Campus, Pathumthani, Thailand
Background : Cognitive deficit is a significant problem, which finally occurs in all schizophrenic patients. It can not be
attenuated by any antipsychotic drugs. It is well known that changes of neuronal density are correlated with learning and
memory deficits. Bacopa monnieri (Brahmi), popularly known as a cognitive enhancer, might be a novel therapeutic agent for
cognitive deficit in schizophrenia by changing cerebral neuronal density. The objective of this study was to determine the
effects of Brahmi on attenuation at cognitive deficit and on the neuronal density in the prefrontal cortex, striatum and cornu
ammonis subfield 1 (CA1) and 2/3 (CA2/3) of hippocampus in sub-chronic phencyclidine (PCP) rat model of schizophrenia.
Material and Method: Rats were assigned to three groups; Group-1: Control, Group-2: PCP administration and Group-3:
PCP + Brahmi. Rats were tested for cognitive ability by using the novel object recognition test. Neuronal density from a serial
Nissl stain sections of the prefrontal cortex, striatum and hippocampus of rat model of schizophrenia were measured by using
Image ProPlus software and manual counting.
Results : Sub-chronic administration of PCP results in cognitive deficits in novel object recognition task. This occurred
alongside significantly increased neuronal density in CA1. The cognitive deficit was recovery to normal in PCP + Brahmi
group and it occurred alongside significantly decreased neuronal density in CA1. On the other hand, significantly increased
neuronal density was observed in CA2/3 of PCP + Brahmi group compared with PCP alone.
Conclusion : Brahmi is a potential cognitive enhancer against schizophrenia. It reduces neuronal density, most likely
glutamatergic neuron, which results in neuronal toxicity and cognitive deficit. Therefore, Brahmi has cognitive enhancement
effect by reducing glutamatergic neuron in CA1. Moreover, it also has neurogenesis effect in CA2/3, which is needed to be
investigated in the further study.
Keywords : Brahmi, Schizophrenia, Animal model, Neuronal density, Novel object recognition
