Fig. 4.

Increased DA- and 5HT-mediated G protein coupling in schizophrenia patients is normalized by chronic treatment with antipsychotics. ON cell membranes from 10 age/sex-matched schizophrenia and control pairs were stimulated with DA or 5HT in the presence of [³⁵S]GTPγS. [³⁵S]GTPγS-bound Gα proteins were immunoprecipitated with antibodies to various Gα proteins. Both DA- and 5HT-induced [³⁵S]GTPγS incorporation were higher in ON cells from schizophrenia subjects (A). The effects of 5-day treatment with 100nM haloperidol, 2 µM clozapine, or vehicle on 5HT-induced G protein coupling were examined in 3 age/sex-matched schizophrenia and control pairs. 5HT-induced [³⁵S]GTPγS binding to Gαs/olf and Gαq/11 was examined. Antipsychotic treatments significantly decreased [³⁵S]GTPγS binding to Gαs and Gαq11 in ON cells from schizophrenia and control subjects. [³⁵S]GTPγS binding was higher in schizophrenia patients without antipsychotic treatment (B). Data represented as means ± SEM (bars). Statistical significance was assessed paired student’s t test, 2 tailed. *P < .05, **P < .01.