Pharmacology, biochemistry, and behavior
February 1, 1998
S Helsley, D Fiorella, R A Rabin et al.
35 citations
In rats trained to recognize the hallucinogen ibogaine, two other hallucinogens—LSD and DOM—partially substituted for ibogaine (63% and 66.4% of responses, respectively). This partial substitution was completely blocked by the 5-HT2A antagonist pirenpirone, indicating that LSD and DOM produce ibogaine-like effects through the 5-HT2A receptor. However, pirenpirone did not block ibogaine itself or its effects from harmaline and noribogaine. Ibogaine, noribogaine, and harmaline showed only micromolar affinity for the 5-HT2A receptor (92.5, 34.5, and 42.5 µM). Ibogaine and harmaline, but not noribogaine, protected the receptor from alkylation. The findings suggest that while ibogaine interacts with 5-HT2A receptors, these interactions are not essential for its discriminative stimulus effects.
Pharmacology, biochemistry, and behavior
July 1, 1999
J C Winter, S Helsley, D Fiorella et al.
14 citations
Pretreatment with the monoamine reuptake inhibitors fluoxetine, fluvoxamine, and venlafaxine increased the discriminative stimulus effects of the hallucinogens LSD, (-)-DOM, and ibogaine in rats trained to recognize these drugs. For 5-MeO-DMT-trained rats, only fluoxetine enhanced drug-appropriate responding. The reuptake inhibitors alone sometimes produced intermediate responding, suggesting partial substitution. Further experiments with (-)-DOM showed that most combinations produced additive rather than truly potentiating effects. The findings extend earlier observations that fluoxetine augments LSD's effects to include other hallucinogens, though the mechanisms and differences between acute and chronic treatment remain unknown.
Pharmacology, biochemistry, and behavior
September 1, 1997
S Helsley, D Fiorella, R A Rabin et al.
9 citations
Ibogaine, at a potentially neurotoxic dose, did not impair rats' ability to learn or perform a maze task. In a study with 12 rats trained in an 8-arm radial maze, those given ibogaine showed similar learning and accuracy as controls but had lower response rates. When given before maze sessions, ibogaine dose-dependently slowed responding without reducing accuracy. When given after sessions, ibogaine-treated rats made fewer errors than controls. The authors conclude that ibogaine failed to produce any harmful effects on learning or task efficiency.