Effect of the selective 5-HT3 receptor antagonists ICS 205-930 and MDL 72222 on 5-HTP-induced head shaking and behavioral symptoms induced by 5-methoxy-N,N,dimethyltryptamine in rats: comparison with some other 5-HT receptor antagonists.
Psychopharmacology – January 01, 1987
Source: PubMed
Summary
Selective 5-HT3 receptor antagonists ICS 205-930 and MDL 72222 significantly reduced head shaking in rats induced by L-5-HTP, yet they were over 600 times less potent than leading drugs like pirenperone. In blocking behavioral symptoms from 5-MeODMT, these compounds displayed over 1000 times less potency compared to pirenperone. This indicates that the head shakes from L-5-HTP are likely mediated by 5-HT2 receptors, suggesting that ICS 205-930 and MDL 72222 have minimal interaction with these receptors in the brain.
Abstract
The effect of the selective 5-HT3 receptor antagonists ICS 205-930 and MDL 72222 on head shaking behavior induced by L-5-HTP and behavioral symptoms induced with 5-methoxy-N,N,-dimethyltryptamine (5-MeODMT) in rats was evaluated. Both drugs dose-dependently reduced L-5-HTP-induced head shaking but were at least 600 times less potent than pirenperone and ketanserin and at least 50 times less potent than methysergide. ICS 205-930 and MDL 72222 were more than 1000 times less potent than pirenperone or methysergide and 100 times less potent than ketanserin in blocking 5-MeODMT-induced forepaw treading and tremor. Since it appears that head shakes induced by L-5-HTP are mediated by 5-HT2 receptors, these data suggest that ICS 205-930 and MDL 72222 do not significantly interact with 5-HT2 receptors in the brain. Furthermore, the data suggest that ICS 205-930 and MDL 72222 lack appreciable antagonistic activity at the 5-HT receptor(s) mediating those behavioral effects induced by 5-MeODMT.