Stimulus effects of ibogaine in rats trained with yohimbine, DOM, or LSD.
Pharmacology, biochemistry, and behavior – December 01, 1992
Source: PubMed
Summary
Ibogaine demonstrates notable effects similar to LSD, with 83% of LSD-trained rats responding appropriately after receiving 20 mg/kg ibogaine. In contrast, yohimbine-trained rats showed only 39.7% correct responses with ibogaine at 15 mg/kg, not significantly different from no treatment. Notably, in DOM-trained rats, ibogaine elicited a distinct response pattern, blocked by pizotyline (BC-105), indicating that both 5-HT2 and potentially 5-HT1A receptors may play a role in ibogaine's stimulus properties. This highlights the complex neuropharmacological interactions involved.
Abstract
The stimulus effects of ibogaine were compared with those of yohimbine, an alpha 2-adrenoceptor antagonist, 2,5-dimethoxy-4-methylamphetamine (DOM), a 5-hydroxytryptamine2 (5-HT2) agonist, and lysergic acid diethylamide (LSD), a nonspecific 5-HT agonist. Rats were trained with either yohimbine (6 mg/kg), DOM (0.6 mg/kg), or LSD (0.1 mg/kg) vs. no treatment in a two-lever discrimination task. Tests of generalization were then conducted with ibogaine. In yohimbine-trained animals, 39.7% of responses following ibogaine (15 mg/kg) were on the drug-appropriate lever, but this response level was not significantly different from no treatment-appropriate responding. A response distribution that was significantly different from responding under both drug and no treatment training conditions was observed in DOM-trained rats after administration of 15 mg/kg ibogaine. Pizotyline (BC-105) blocked all DOM-appropriate responding produced by ibogaine. In LSD-trained animals, 20 mg/kg ibogaine mimicked LSD. Pizotyline blocked LSD-appropriate responding produced by ibogaine in five of six animals. The present data suggest the involvement of 5-HT2 receptor activity, and the possibility of a 5-HT1A contribution, in the stimulus properties of ibogaine.