title: Chronic haloperidol and chlorpromazine treatment alters in vitro beta-endorphin metabolism in rat brain.
abstract: To determine if chronic haloperidol (3.0 mg/kg per day) or chlorpromazine (4.2 mg/kg per day) treatment alters central beta-endorphin metabolism, haloperidol and chlorpromazine were perfused via Alzet minipumps into male Sprague-Dawley rats for 8 days. Crude twice-washed membranes, purified synaptic plasma membranes and Golgi-enriched membranes, respectively, were isolated from rat brains and time course incubated with beta-endorphin. All samples were analyzed by high resolution, reversed-phase high performance liquid chromatography. The half-lives of beta-endorphin for animals treated with haloperidol or chlorpromazine were not statistically different from control animals at the crude washed membranes. At the purified synaptic plasma membranes, however, the half-lives of beta-endorphin from haloperidol (t 1/2 = 45.1 min)- and chlorpromazine (t1/2 = 47.0 min)-treated animals were significantly decreased as compared to the control animals (t1/2 = 78.0 min). The half-life of beta-endorphin at the Golgi-enriched membranes was increased for haloperidol (t1/2 = 112.3 min) and chlorpromazine (t1/2 = 103.0 min)-treated animals when compared to control animals (t1/2 = 80.2 min). The findings indicate a differential effect of the dopamine receptor antagonists haloperidol and chlorpromazine on the extracellular fate at the synaptic plasma membranes of beta-endorphin and the intracellular processing at the Golgi-enriched membranes in vitro.
authors.affiliation: Department of Pharmacology, University of Arizona, College of Medicine, Tucson 85724.
authors.forename: P N
authors.initials: PN
authors.lastname: Konings
authors.forename: A
authors.initials: A
authors.lastname: Culling-Berglund
authors.forename: T P
authors.initials: TP
authors.lastname: Davis
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002746:Chlorpromazine / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D006056:Golgi Apparatus / Q000378:metabolism; D006207:Half-Life; D006220:Haloperidol / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008566:Membranes / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D001615:beta-Endorphin / Q000032:analysis / Q000096:biosynthesis / Q000493:pharmacokinetics*
chemical_list: D001615:beta-Endorphin; D006220:Haloperidol; D002746:Chlorpromazine