Expression of vasopressin mRNA in the hypothalamus of individuals with a diagnosis of schizophrenia

OBJECTIVE: This study investigates the expression of mRNA encoding vasopressin in the hypothalamus of autopsy brains of individuals diagnosed with schizophrenia. METHODS: Ten brains of individuals with schizophrenia and 10 brains from individuals without any disease were examined during autopsy. The hypothalamic block was dissected and immersion fixed in paraformaldehyde, sucrose substituted, frozen, and cut into 20‐µm‐thick coronal cryostat sections. The sections were hybridized with an S‐35‐labeled DNA antisense oligo probe and after washing covered by an X‐ray film. The hybridization signals on the films were transferred to a computer and densitometrically quantified. RESULTS: The densitometry signals showed a statistically significant lower mRNA expression (53% decrease; p = 0.014) in the paraventricular nucleus of the individuals with schizophrenia compared to the controls. In the supraoptic nucleus, the decrease in the group with schizophrenia was 39% compared to the controls, but this decrease was not statistically significant (p = 0.194). CONCLUSIONS: Our results show a low expression of mRNA encoding vasopressin in the paraventricular nucleus of the individuals with schizophrenia. We suggest that vasopressin is not directly involved in the pathogenesis of schizophrenia, but might influence schizophrenic symptoms via vasopressin receptors located in the social behavioral neural network in the forebrain.