Effects of quipazine and of tryptamine on self-stimulation of median raphé nucleus and of lateral hypothalamus in rats.
Separate groups of male Wistar rats were trained to lever press on a continuous reinforcement schedule under which behaviour was maintained by electrical stimulation of the median raphé nucleus (N = 6) or the lateral hypothalamus (N = 6). The effects of several doses of quipazine (2.5-7.1 mg/kg) and of tryptamine (10-80 mg/kg) were assessed with each group. Administration of quipazine resulted in a decrease of median raphé self-stimulation at 5.0 and 7.1 mg/kg. This compound had no statistically significant effect on lateral hypothalamic self-stimulation. Administration of tryptamine resulted in significant decreases in self-stimulation at both sites, however, whereas the effects of this drug were significant at 20, 40 and 80 mg/kg with median raphé self-stimulation, a significant decrease in lateral hypothalamic self-stimulation was only observed at 80 mg/kg. As baseline response rates differed in the two self-stimulation sites, a second group of animals with lateral hypothalamic sites (n = 6) were tested with quipazine (2.5-7.1 mg/kg) at an overall baseline response rate matched to that of the median raphé group. Although a tendency to decrease self-stimulation rates was found in this group, these results were not significant. These data suggest, therefore, that median raphé self-stimulation is more sensitive than lateral hypothalamic self stimulation to disruption by the effects of quipazine and tryptamine.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D007026:Hypothalamic Area, Lateral / Q000502:physiology*; D008297:Male; D011804:Quinolines / Q000494:pharmacology*; D011814:Quipazine / Q000494:pharmacology*; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012653:Self Stimulation / Q000187:drug effects*; D014363:Tryptamines / Q000494:pharmacology*
D011804:Quinolines; D014363:Tryptamines; C030820:tryptamine; D011814:Quipazine