Erowid References Database
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Hamon M, Bourgoin S, Enjalbert A, Bockaert J, Hery F, Ternaux JP, Glowinski J.
“The Effects of Quipazine on 5-HT Metabolism in the Rat Brain”.
Naunyn Schmiedebergs Arch Pharmacol. 1976;294(1):99-108.
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Abstract
The effects of quipazine (Q, Miles) on brain 5-HT metabolism was studied. Methods Male Charles River rats (250-350 g) were kept for 10 days in a controlled environment. Drugs were given i.p. and animals were killed at intervals, brain was removed, brain stem and 2 forebrain were kept and cerebellum discarded. In in vitro studies brain stem slices were incubated in a medium containing 10-4 M pargyline (Abbott) 10-6 - 2 x 10-5 M Q 10-6 - 10-5 M chlorimipramine (CIBA-Geigy) and/or 10-5 M LSD (Sandoz); conversion of 3H-tryptophan to 3H-5-HT and 3H-5-HIAA was determined. Uptake and release of 3H-5-HT were studied using a medium containing 10-4 M pargyline, various concentrations of Q or 10-7- 10-4 M chlorimipramine. MAO activity was determined using a medium containing 0 - 10-4 M Q. 3H-5-HT and 5-MT. Adenylate cyclase (AC) activity of whole colliculi homogenate of newborn rats was determined. Results Q i.p. at 10 mg/kg induced hyperactivity which lasted for 30 to 45 min. 5-HT levels in the brain stem increased, whereas 5-HIAA levels in brain stem and forebrain were reduced. Given 45 min before )800 mg/kg i.p. Ro-4-4602 (Roche), Q reduced the rate of accumulation of 5-HTP in brain stem (-24%) and in the forebrain (-28%); the decrease in 5-HT normally seen 30 min after Ro-4-4602 was not detected after Q. Q i.p. at 10 mg/kg reduced 5-HT synthesis, but direct addition to the medium at 10-6, 10-5 M had no effect on brain stem 5-HT levels. Q or chlorimipramine at 10-6 M. led to increased efflux of 3H-5HT from brainstem slices. Both agents i.p. at 10 mg/kg, protected rats against the 5-HT depleting effects of 100 mg/kg i.p. H75/12 (Haessle). Q at low concentrations was a weaker inhibitor of initial accumulation of 3H-5-HT than chlorimipramine but the difference was not present at 10,uM. Q at 5 x 10-7 M led to a marked reduction of 3H-5-HT uptake from a crude brain stem synaptosomal preparation. (Ki = 1.38 x 10-7M for chlorimipramine Kl = 2.2 x 10-8M). Unlike LSD Q did not activate the 5-HT sensitive AC. Q at 10 mg/kg i.p. or LSD at 2 mg/kg i.p prevented the increase in 5-HIAA induced by methiothepin, a potent blocker of 5-HT receptors. Q gave non-competitive inhibition of MAO at high concentrations (Ki = 3:0 x 10 5 M).
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