title: Effects of 2% sodium chloride imbibition on various opiate related hyperphagic conditions.
abstract: Dynorphin is one of the most potent appetite stimulants among the endogenous opioids. In this study, we describe the anorexic effects of 5 days of forced 2% NaCl drinking in rats, a regimen which depletes vasopressin as well as dynorphin in the neurohypophysis. Feeding induced by direct activation of kappa-opioid receptors with ketocyclazocine was unaffected by the NaCl regimen. However, 2% NaCl imbibition reduced 2-deoxy-D-glucose (2-DG) induced feeding by 65% and spontaneous nocturnal feeding by 38%. Feeding subsequent to 24 hour food deprivation was not decreased. Naloxone-resistant hyperphagia induced by insulin and spontaneous daytime feeding were also not reduced. The combination of naloxone (3.0 mg/kg) and the NaCl regimen produced an additional 50% reduction in 2-DG induced feeding and an extra 40% decrease in nocturnal feeding. Naloxone, given with 2% NaCl to food deprived animals, retained its appetite suppressing activity, indicating that the NaCl regimen did not deplete the endogenous opioid which mediates food deprivation hyperphagia. These results demonstrate that 2% NaCl imbibition suppresses certain opioid mediated hyperphagias. However, the failure of 2% NaCl to affect all of the naloxone-sensitive types of feeding and the independence of naloxone-sensitive and NaCl-sensitive components suggests that NaCl drinking does not deplete dynorphin in the brain areas which mediate opiate-sensitive hyperphagias.
authors.forename: H U
authors.initials: HU
authors.lastname: Bryant
authors.forename: M T
authors.initials: MT
authors.lastname: Lowy
authors.forename: P V
authors.initials: PV
authors.lastname: Malven
authors.forename: T D
authors.initials: TD
authors.lastname: Steele
authors.forename: G K
authors.initials: GK
authors.lastname: Yim
mesh_terms: D000818:Animals; D003496:Cyclazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D004399:Dynorphins / Q000494:pharmacology; D016314:Ethylketocyclazocine / Q000031:analogs & derivatives*; D005247:Feeding Behavior / Q000187:drug effects*; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D007328:Insulin; D009294:Narcotics; D011957:Receptors, Opioid; D009270:Naloxone; D012965:Sodium Chloride; D016314:Ethylketocyclazocine; C012395:ketazocine; D004399:Dynorphins; D003847:Deoxyglucose; D003496:Cyclazocine