title: Platelet alpha 2-adrenergic receptors in schizophrenic patients before and after phenothiazine treatment.
abstract: 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 weeks 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. These observations suggest that schizophrenia might be associated with abnormal noradrenergic function that is reflected by a decreased number of platelet alpha 2-adrenergic receptors.
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002746:Chlorpromazine / Q000627:therapeutic use*; D002908:Chronic Disease; D003000:Clonidine / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011941:Receptors, Adrenergic / Q000187:drug effects* / Q000378:metabolism; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy*; D015016:Yohimbine / Q000097:blood
chemical_list: D011941:Receptors, Adrenergic; D015016:Yohimbine; D003000:Clonidine; D002746:Chlorpromazine; D009638:Norepinephrine