Supersensitivity to L-5-hydroxytryptophan after 5,7-dihydroxytryptamine injections in desmethylimipramine- and nomifensine-pretreated rats: behavioral evidence for postsynaptic supersensitivity.
The behavioral syndrome induced by L-5-hydroxytryptophan (L-5-HTP) in rats was used to study the supersensitivity to L-5-HTP and 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) which develops after unilateral intracerebroventricular (ICV) injections of 200 microgram 5,7-dihydroxytryptamine (5,7-DHT). Pretreatment of the animals with a combination of desipramine and nomifensine was found to protect dopamine neurones better than desipramine alone. Maximal behavioral supersensitivity to L-5-HTP and 5-MeODMT was found as early as 24 h after injection of the neurotoxin, even in the presence of the specific 5-HT uptake inhibitor CGP 6085 A, or the MAO-A inhibitor clorgyline. The results indicate that a quickly occurring postsynaptic event contributes to the development of behavioral supersensitivity after ICV injections of 5,7-DHT.
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology*; D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D003891:Desipramine / Q000494:pharmacology*; D004102:Dihydroxytryptamines / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology*; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism; D009627:Nomifensine / Q000494:pharmacology*; D051381:Rats; D013569:Synapses / Q000187:drug effects*
D004102:Dihydroxytryptamines; D007546:Isoquinolines; D008732:Methoxydimethyltryptamines; D018377:Neurotransmitter Agents; D009627:Nomifensine; D015116:5,7-Dihydroxytryptamine; D006916:5-Hydroxytryptophan; D003891:Desipramine