Serotonin receptor sensitivity after acute and chronic treatment with mianserin.
The chronic administration of mianserin for 14 days leads to a marked decrease in the maximal number of serotonin2 (5-HT2) binding sites in brains of rats and mice with no change in the KD values. The decrease in [3H]spiroperidol binding to the 5-HT2 site in rats was most pronounced in the frontal cortex with only minor changes in hippocampus and pons-medulla. The 5-HT1 site was largely unaffected. The decrease in the Bmax for 5-HT2 site also occurred after a single dose of mianserin, although mianserin was more potent when given chronically. Maximal inhibition of binding occurred with a chronic dose of 0.5 mg/kg. The greatest decrease was found 48 hr after single or repeated doses with a gradual return to normal levels within 10 days. The administration of mianserin also leads to a decrease in 5-methoxy-N,N-dimethyltryptamine-induced head twitches in mice assayed 48 and 96 hr after a single or repeated doses, which is presumably correlated with the decrease in the 5-HT2 binding site assayed in vitro.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects; D003984:Dibenzazepines / Q000494:pharmacology*; D005260:Female; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D008803:Mianserin / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D013997:Time Factors
D003984:Dibenzazepines; D008732:Methoxydimethyltryptamines; D011985:Receptors, Serotonin; D008803:Mianserin