5-HT2A and muscarinic receptors in schizophrenia: a postmortem study

Although evidence suggests that 5-HT2A and muscarinic M1/M4 receptors are implicated in the pathology of schizophrenia, the results are not conclusive. In the present study we tested the hypothesis that binding of 5-HT2A and M1/M4 receptors is altered in the postmortem brain of schizophrenia subjects. Quantitative autoradiography was employed to measure [3H]ketanserin binding to 5-HT2A receptors and [3H]pirenzepine binding to both M1 and M4 receptors in Brodmann's area 9 (BA9), caudate/putamen, and the hippocampal formation from six schizophrenic and six control subjects. A significant reduction in the density of 5HT2A receptors in BA 9 of schizophrenic subjects was observed (p = 0.036). No significant difference was observed in the density of 5HT2A receptors in the hippocampus or caudate/putamen between the two groups. No significant changes in the density of M1/M4 receptors was observed in these three regions between the two groups. These findings support a possible involvement of the serotonergic system in the pathology of schizophrenia.