Objective: In recent years, abnormal changes in the endocannabinoid system have been found in schizophrenia. The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In this study, we investigated the binding density of cannabinoid CB1 receptors in the STG of schizophrenia patients compared to control subjects. Methods: Quantitative autoradiography was used to investigate the binding densities of [3H] SR141716A (a selective antagonist) and [3H]CP-55940 (an agonist) to the CB1 receptors in the STG. Post-mortem brain tissue was obtained from the NSW Tissue Resource Centre (Australia). Results: Contrasting to previous findings in the alterations of CB1 receptor densities in the prefrontal, anterior and posterior cingulate cortex of schizophrenia, which were suggested to be associated to impairment of cognition function, no significant
difference was found between the schizophrenia and control cases in both [3H]SR141716A and [3H]CP-55940 binding. Conclusion: We suggest that CB1 receptors in the STG are not involved in the pathology of schizophrenia and the auditory hallucination symptom of this disease.