title: Hypothalamic neuronal responses to iontophoretic application of morphine in rats.
abstract: Effects of thermal stimulation of the scrotum and of iontophoretic application of morphine on the activity of neurones in the preoptic anterior hypothalamic area were observed in 30 urethane-anaesthetised rats. The proportions of cold-responsive, warm-responsive and thermally unresponsive units were 20.7, 28.3 and 51%, respectively, of the total number of neurones tested. Iontophoretic application of morphine to neurones in the preoptic anterior hypothalamic area in rats resulted in excitation of the majority of cold-responsive cells and inhibition of the majority of warm-responsive cells tested. However, most of the thermally unresponsive cells were unaffected by application of morphine. These results provide a neuronal basis for the hypothesis that morphine, when administered directly into the hypothalamus, facilitates heat production and inhibits heat loss, which leads to hyperthermia.
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003080:Cold Temperature; D006358:Hot Temperature; D007032:Hypothalamus, Anterior / Q000502:physiology*; D007478:Iontophoresis; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009020:Morphine