Interactions of metergoline with diazepam, quipazine, and hallucinogenic drugs on a conflict behavior in the rat
Psychopharmacology March 1, 1982 R. L. Commissaris, R. H. Rech
Diazepam dramatically increased punished responding in rats, while the hallucinogens LSD and DOM produced only modest increases, and quipazine had no significant effect. Metergoline pretreatment did not affect punished responding or alter diazepam's effects, but it antagonized LSD's weak increase. Diazepam, quipazine, LSD, and DOM all decreased unpunished responding in a dose-dependent manner. Metergoline shifted the dose-response curves for quipazine and DOM rightward but shifted diazepam's curve leftward. These results suggest that changes in brain serotonin activity do not underlie diazepam's large effect on punished behavior, and that the drugs reduce unpunished responding through different neuropharmacological mechanisms.