LSD, mescaline and serotonin injected into medial raphe nucleus potentiate apomorphine hypermotility
European Journal of Pharmacology November 1, 1981 Heidrun Fink, Wolfgang Oelssner 44 citations
Microinjections of LSD, mescaline, and serotonin into the medial raphe nucleus of rats strongly potentiated the increase in locomotor activity caused by apomorphine. This potentiating effect of LSD or serotonin was blocked by simultaneous injections of methysergide or cyproheptadine into the same brain region. Injections of the same doses of LSD into the dorsal raphe nucleus or of LSD and mescaline into the nucleus accumbens did not affect locomotor activity, while higher doses into the nucleus accumbens inhibited both spontaneous and apomorphine-stimulated activity. The findings suggest that low systemic doses of hallucinogens potentiate behavior by preferentially acting on the serotonergic system in the medial raphe nucleus.