Rapid down-regulation of S2 serotonin receptors by antidepressants: noradrenergic-serotonergic interactions.
Mianserin stereoselectively decreases rat cortical S2 binding, the (+)enantiomer having higher potency. This and other data suggest that an alpha-2 receptor is unlikely to contribute to the mechanism of rapid S2 down-regulation by mianserin. Yohimbine, an alpha-2 antagonist which enhances desipramine-induced S2 decreases, was not dependent on NE or 5-HT release for its effect. Depletion of NE by 75% or 5-HT by 94% did not alter the ability of yohimbine and desipramine to decrease binding. These results raise previously unsuspected mechanisms involved in acute down-regulation of S2 binding by mianserin and yohimbine.
D000818:Animals; D001667:Binding, Competitive; D003984:Dibenzazepines / Q000494:pharmacology*; D010134:Fenclonine / Q000494:pharmacology; D006892:Hydroxydopamines / Q000378:metabolism; D008297:Male; D008803:Mianserin / Q000378:metabolism / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology; D013237:Stereoisomerism; D015016:Yohimbine / Q000378:metabolism
D003984:Dibenzazepines; D006892:Hydroxydopamines; D011942:Receptors, Adrenergic, alpha; D011985:Receptors, Serotonin; D008803:Mianserin; D015016:Yohimbine; D012701:Serotonin; D010134:Fenclonine; D009638:Norepinephrine