title: Serotonergic mediation of reward within the medial raphe nucleus: some persistent problems in interpretation.
abstract: Adult male Sprague Dawley rats were implanted with unipolar stimulating electrodes aimed at the medial forebrain bundle (MFB) or the medial raphe nucleus (MR). All MFB implanted subjects self-stimulated at high stable rates for at least three weeks. Only a minority (1/3) of MR rats self-stimulated at all. Rates for the MR group were considerably more variable, and could not be maintained for more than two weeks. Treatment with methysergide increased MFB self-stimulation but decreased MR self-stimulation. While this result suggests serotonergic mediation of self-stimulation this conclusion must be interpreted cautiously since parachlorophenylalanine (PCPA) reinstated self-stimulation in raphe animals which had spontaneously ceased responding.
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology; D001933:Brain Stem / Q000502:physiology*; D010134:Fenclonine / Q000494:pharmacology; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D012201:Reward / Q000187:drug effects; D012653:Self Stimulation / Q000187:drug effects; D012701:Serotonin / Q000502:physiology*
chemical_list: D012701:Serotonin; D010134:Fenclonine; D008784:Methysergide