however , displacement studies using 5-methoxytryptamine , lysergic acid diethylamide ( lsd ) , 2-bromo-lysergic acid diethylamide ( bol ) , methysergide , and spiperone as competing ligands suggested the existence of subclasses of [ 3h ] 5-ht binding sites because the hill coefficients were less than unity .
C0000589
5-methoxytryptamine
C0036751
5-ht