British Journal of Pharmacology
September 26, 2014
Ryan A. Gregg, Michael H. Baumann, John S. Partilla et al.
79 citations
The synthetic cathinone mephedrone (MEPH) has two mirror-image forms (enantiomers), R-MEPH and S-MEPH, which produce different effects in rats. Both enantiomers similarly release dopamine, but R-MEPH is much weaker than S-MEPH at releasing serotonin. R-MEPH caused more repetitive movements, produced sensitization to those movements after repeated doses, and was rewarding in a conditioned place preference test, whereas S-MEPH was not. In a brain-stimulation reward test, both enantiomers showed biphasic effects, but R-MEPH produced greater facilitation. These findings indicate that R-MEPH's stronger dopamine actions and weaker serotonin actions make it more stimulant-like than S-MEPH.
Behav Pharmacol
July 1, 2026
Razeen J. Akbar, Amy D. Stringer, Sonita Wiah et al.
Psilocybin, a psychedelic compound, causes repetitive, stereotyped movements and reduces defensive reactions in planarian flatworms. These effects are mediated by the neurotransmitter serotonin (5-hydroxytryptamine). The findings suggest that psilocybin's behavioral actions in this simple animal model are linked to serotonergic signaling.
Behavioural Pharmacology
September 25, 2025
Saadet Inan, Paige E. Morris, Scott M. Rawls et al.
Psilocybin, the active compound in Psilocybe mushrooms, reduced pain-related behaviors in adult male rats exposed to formalin-induced noxious stimuli, a model of both acute and persistent inflammatory pain. Doses of 0.1 and 0.3 mg/kg significantly decreased flinching and licking during both early and late pain phases. Pretreatment with volinanserin, a selective blocker of the 5-HT 2A receptor, eliminated this pain-relieving effect, indicating that psilocybin produces analgesia at least partly by activating that receptor.