Lysergine, also known as 9,10-didehydro-6,8β-dimethylergoline, is an ergot alkaloid and serotonin receptor agonist of the ergoline family. It is a minor constituent of ergot.
Pharmacology Lysergine shows selectivity for activation of the serotonin 5-HT2A receptor over several other closely related serotonin receptors (54-fold over the 5-HT2B receptor, 38-fold over the 5-HT2C receptor, and 127-fold over the 5-HT1A receptor). The drug is a partial agonist of the 5-HT2A receptor with moderate intrinsic activity (Emax = 57%).
+ Lysergine activation of serotonin receptors 5-HT1A 5-HT2A 5-HT2B 5-HT2C EC50 Emax EC50 Emax EC50 Emax EC50 Emax 342 ± 23 2.7 ± 1.6 57% 145 ± 54 36% 103 ± 9 42% Notes: EC50 values are nanomolar (nM) and EC50 values are mean ± SEM.
An analogue of lysergine, (+)-13-fluorolysergol, is an even more selective agonist of the 5-HT2A receptor than lysergine (EC50 for 5-HT2B and 5-HT2C of >10,000nM). However, this compound has relatively weak maximal efficacy in activating the receptor (Emax = 17%).
Chemistry Analogues Isotryptamine or JRT-type analogues of lysergine have been described.
See also Descarboxylysergic acid Lysergic acid Ergine Lysergol SDZ SER-082
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