Effect of intrahypothalamic injection of [D-Ala2,D-Leu5]enkephalin on feeding and temperature in the rat.
The effectiveness of the delta-opioid agonist [D-Ala2,D-Leu5]enkephalin (DADLE) in eliciting alterations in feeding and core temperature in rats was compared to morphine. When injected into the ventromedial hypothalamus this peptide caused a dose-related increase in feeding which was rapid in onset and of short duration, and a short-lived increase in temperature. Neither of these effects was blocked by the intrahypothalamic injection of naloxone. The alpha-adrenoreceptor antagonist phentolamine significantly reduced DADLE-stimulated feeding, although it did not counteract the hyperthermia. Since the delta-opioid agonist DADLE is more potent than the mu-agonist, morphine, and produces its effect more rapidly, the delta-opiate receptor may have an influence on the regulation of feeding.
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004743:Enkephalin, Leucine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016308:Enkephalin, Leucine-2-Alanine; D005247:Feeding Behavior / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000008:administration & dosage; D009270:Naloxone / Q000008:administration & dosage; D010646:Phentolamine; D051381:Rats; D011919:Rats, Inbred Strains
D009270:Naloxone; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D009020:Morphine; D010646:Phentolamine