Tardive dyskinesia in bipolar disorders: possible role of pineal melatonin

Melatonin administration increases the affinity of D2 dopamine receptors in the rat striatum

Rats receive melatonin (MEL) (476 +/- 6.5 microg/kg/day) via their drinking water for 2 weeks. At the end of this period, the density of D2 dopamine (DA) receptors and their affinity for [3H]-YM-09151-2 are measured in the striatum. MEL treatment increases the apparent affinity (decreases the Kd) of D2 DA receptors for [3H]YM-09151-2 by 48%, while it does not significantly alter the density (Bmax). These findings indicate that the affinity of D2 DA receptors in the striatum is influenced by exposure to MEL. The possible implications of these results are discussed.

Neuroradiological covariates of drug-induced parkinsonism and tardive dyskinesia in schizophrenia

Computed tomographic (CT) studies have demonstrated structural brain abnormalities including cortical atrophy and enlarged lateral ventricles in a subset of schizophrenic patients including those with abnormal involuntary movements. In the following series of studies, we present our findings pertaining to neuroradiological covariates of drug-induced Parkinsonism and Tardive dyskinesia in schizophrenic patients. In these studies we have explored the relationship of Parkinsonism and Tardive dyskinesia to pineal and choroid plexus calcification. In addition, we also investigated the relationship of pineal calcification to schizophrenia, and specifically to the paranoid and nonparanoid subgroups. In a further series of studies, we investigated the neuroradiological covariates of disorders of gait and posture as well as tremor in schizophrenic patients with drug-induced Parkinsonism. In addition, we explored the relationship of Tardive dyskinesia and its subsyndromes to CT scan measurements of cortical and subcortical atrophy in schizophrenia. Our findings highlight the significance of the pineal gland in the pathophysiology of schizophrenia and drug-induced movement disorders. Furthermore, these studies underscore the heterogeneity of Parkinsonism and Tardive dyskinesia.