Platelet alpha 2-adrenergic receptors in schizophrenic patients before and after phenothiazine treatment
Rice, H.E.; Smith, C.B.; Silk, K.R.; Rosen, J.
Psychiatry Research 12(1): 69-77
1984
ISSN/ISBN: 0165-1781 PMID: 6087398 Document Number: 230373
The specific binding to isolated platelet membranes of 3H-clonidine, an .alpha.2-adrenergic receptor partial agonist, and 3H-yohimbine, an .alpha.2-adrenergic receptor antagonist, was measured in male, drug-free schizophrenic patients. The maximum number of binding sites (Bmax) for 3H-yohimbine was significantly lower in these patients than in normal subjects. Treatment with chlorpromazine (CPZ) for 2 wk further decreased the Bmax for both ligands. Plasma catecholamine levels were determined before and after treatment. Before treatment, levels of dopamine and norepinephrine (NE) were within a normal range, while epinephrine (E) levels were significantly elevated. CPZ treatment significantly increased plasma NE levels, but decreased E levels to a normal range. Schizophrenia might be associated with abnormal noradrenergic function that is reflected by a decreased number of platelet .alpha.2-adrenergic receptors.