A probable role for norepinephrine in feeding after hypothalamic injection of morphine.
When morphine is instilled directly into the ventromedial hypothalamus of rats there is a latent period followed by a prolonged bout of feeding. This enhanced activity may be mediated by the release of norepinephrine; for morphine-induced feeding was depressed by the alpha-adrenergic receptor blocker phentolamine. Several neurotransmitter agonists and antagonists failed to duplicate this action: propranolol, serotonin, methysergide, apomorphine and haloperidol were ineffective in modifying ingestion elicited after morphine. Unlike apomorphine, dopamine augmented morphine's feeding effect. This difference may exist because dopamine acts as a precursor for norepinephrine formation in local ventromedial hypothalamic neurons.
D000818:Animals; D004347:Drug Interactions; D005247:Feeding Behavior / Q000187:drug effects* / Q000502:physiology; D007031:Hypothalamus; D007267:Injections; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009638:Norepinephrine / Q000502:physiology*; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D009020:Morphine; D011433:Propranolol; D009638:Norepinephrine; D008784:Methysergide; D010646:Phentolamine