Behavioural Pharmacology
April 1, 1995
Lisa E. Baker, Jonathan M. Broadbent, E. K. Michael et al.
52 citations
In rats trained to distinguish either the (+)- or (-)-isomer of MDMA from saline, both isomers of MDMA and MDA fully substituted for the training drugs. Stimulants like amphetamine and cocaine did not substitute. Hallucinogens such as DOM, LSD, and mescaline did not fully substitute for (+)-MDMA; LSD substituted for (-)-MDMA only at a specific dose. The serotonin-releasing agents fenfluramine and p-chloroamphetamine substituted partially or fully for both isomers. Serotonin receptor antagonists pirenpirone and metergoline did not consistently block MDMA's effects. The findings suggest that serotonin release, but not action at 5-HT(2) receptors, is important for the discriminative stimulus effects of MDMA isomers.
Behavioural Pharmacology
December 1, 2020
Keli A. Herr, Lisa E. Baker
9 citations
In rats trained to distinguish LSD from saline, the drug's effects were largely similar between males and females, though some differences emerged with other substances. Both sexes showed comparable substitution by serotonergic hallucinogens. Partial substitution by MDMA, MDA enantiomers, and synthetic cathinones differed modestly between sexes. Dopamine antagonists did not block the LSD cue and suppressed behavior more in males. The serotonin antagonist MDL 100,907 blocked LSD discrimination in both sexes, but complete blockade occurred at lower doses in males. These findings confirm the central role of serotonin in LSD's effects and extend this to females, suggesting further research on sex differences in psychedelic effects is warranted.
Psi Chi Journal of Psychological Research
January 1, 2022
Catherine N. Conway, Lisa E. Baker
6 citations
LSD produces transient anxiogenic, not anxiolytic, effects in rats. In a light/dark test, rats given LSD entered the brightly lit compartment less often and spent less time there, in a dose-dependent manner. In an elevated plus maze, rats tested 48 hours after the last of five LSD injections entered and spent more time in closed arms than open arms, indicating anxiety; this effect was absent in rats tested 72 hours after the last injection. The authors suggest that because psychedelic-assisted psychotherapy shows positive clinical outcomes for anxiety and depression, different preclinical models may be needed to understand the therapeutic mechanisms of serotonergic hallucinogens.