IBOGAINE POSSESSES A SELECTIVE AFFINITY FOR SIGMA(2) RECEPTORS

The alkaloid ibogaine is potentially useful to reduce craving for seve ral drugs of abuse, but its mechanism of action is not known. In the c urrent study, in vitro studies were conducted in order to determine th e affinity of ibogaine for sigma receptors. Our results indicate that ibogaine has a relatively high affinity for sigma(2) receptors (K-i = 90.4 and 250 nM) and a significantly lower affinity for sigma(1) recep tors (K-i = 9310 nM). These data suggest that ibogaine may have a high er affinity at sigma(2) receptors than any other known CNS receptor. I ts low affinity for sigma(1) receptors also suggests that ibogaine may be a suitable lead compound for structure-activity relationship studi es aimed at developing sigma(2)-selective ligands.