Science
April 30, 1982
Francis J. White, James B. Appel
67 citations
Lisuride, a nonhallucinogenic ergot derivative, shares many pharmacological effects with its hallucinogenic counterpart, lysergic acid diethylamide (LSD). Using animals trained to discriminate between the two drugs, researchers found that the LSD cue resembles that of the serotonin agonist quipazine, while the lisuride cue resembles that of the dopamine agonist apomorphine. These findings support the hypothesis that serotonin plays a key role in the hallucinogenic effects of LSD.
European Journal of Pharmacology
January 1, 1989
James B. Appel, Patrick M. Callahan
34 citations
Rats trained to distinguish mescaline (10 mg/kg) from saline showed that the mescaline cue generalized to high doses of the 5-HT2 agonists DOM, LSD, and psilocybin, while generalization to 5-HT1 agonists was unclear. The mescaline cue was blocked by high doses of 5-HT2 antagonists (ketanserin, LY-53857, pirenperone) but not by less selective serotonin (metergoline) or dopamine (SCH-23390, haloperidol) antagonists. These results suggest that 5-HT2 receptors are involved in the stimulus properties of mescaline.
Psychopharmacology
February 1, 1982
Jon Koerner, James B. Appel
19 citations
Rats can distinguish the tryptamine hallucinogen psilocybin from saline in a two-lever choice task. The psilocybin cue generalizes to psilocin and LSD, but not to mescaline, suggesting that the hallucinogenic effects of these drugs in humans may not align with their discriminative stimulus functions in animals, and that these compounds may not belong to a single drug class.
Pharmacology Biochemistry and Behavior
May 1, 1977
James A. Joseph, James B. Appel
18 citations
Two experiments using a fixed ratio schedule of water reinforcement tested whether serotonin-depleting agents alter sensitivity to a low dose of LSD (0.02 mg/kg). Both p-chloroamphetamine (PCA) and 5,7-dihydroxytryptamine (5,7-DHT) reduced whole-brain serotonin, but only 5,7-DHT increased sensitivity to LSD, disrupting bar-press behavior 12 days after administration. PCA did not produce this effect. However, four PCA-treated animals that showed no increased sensitivity did exhibit behavioral disruption to LSD when pretreated with p-chlorophenylalanine. The pattern of serotonin depletion required for LSD sensitivity may be specific.
Pharmacology Biochemistry and Behavior
September 1, 1975
Isaac Greenberg, D. M. Kuhn, James B. Appel
17 citations
Male albino rats learned to press either a left or right lever depending on which drug they had received 30 minutes earlier. One group discriminated between 1.9 mg/kg of delta9-THC and a vehicle control; another group discriminated between 1.0 mg/kg of delta9-THC and 1.0 mg/kg of psilocybin. The results confirmed that delta9-THC can serve as a discriminative stimulus controlling behavior. Because rats reliably chose different levers after delta9-THC versus psilocybin, the two drugs likely produce distinct internal states in rats.