Ibogaine (12-methoxyibogamine) exhibited moderate affinity for sigma 2 sites (Ki = 201 nM) and low affinity for sigma 1 sites (Ki = 8554 nM), thus showing 43-fold selectivity for sigma 2 receptors. Tabernanthine (13-methoxyibogamine) and (+/-)-ibogamine had sigma 2 Ki = 194 nM and 137 nM, respectively. However, they showed 3- to 5-fold higher sigma 1 affinity compared to ibogaine, resulting in...
Previous work demonstrated two high-affinity PCP binding sites in guinea pig brain labeled by [3H]TCP (1-(1-[2-thienyl]cyclohexyl)piperidine): site 1 (N-methyl-D-aspartate [NMDA]-associated) and site 2 (dopamine-reuptake complex associated). The present study examined brain membranes prepared from various species, including human, for the presence of site 2, defined as binding in the presence...
Recently, the presence of two high affinity binding sites for phencyclidine were described in guinea pig brain, with one site coupled to the glutamate excitatory amino acid receptor, specifically activated by N-methyl-D-aspartate (NMDA) (site 1) and the other site associated with the dopamine (DA) reuptake carrier (site 2). Phencyclidine and its analogs, as well as the benzomorphan opiates, are...