Regional brain dysregulation of Ca2+-handling systems in ketamine-induced rat model of experimental psychosis

Abstract

Chronic N-methyl-D-aspartate receptor (NMDAR) antagonist treatment can provide valuable neurochemical and neuroanatomical models of experimental psychosis. One such antagonist, ketamine, with its short half-time and well-documented psychotomimetic action, has cognitive effects resembling various aspects of schizophrenia-like symptoms. In order to obtain insights into possible relationships between Ca2+ homeostasis and schizophrenia-related symptoms, we investigate the effects of chronic ketamine administration on intracellular Ca2+ levels in various brain regions and on the expression level of key members of the neuronal Ca2+-handling system in rats. We show increased intracellular [Ca2+] in all of the examined brain regions following ketamine treatment but an altered cytosolic Ca2+ level correlated with hyperlocomotor activity was only established for the cortex and striatum. Our findings also suggest that an imbalance in the expression between the calcium “on” and “off” systems contributes to the deregulation of brain Ca2+ homeostasis in our ketamine-induced model of experimental psychosis. Identification of the genes whose expression is affected by ketamine treatment indicates their involvement as putative etiological factors in schizophrenia.