| Abstract: |
Naloxone benzoylhydrazone (NalBzoH) is a selective, short-acting agonist at the κ3 opioid receptor and a slowly dissociating potent antagonist at the mu opioid receptor. Given the important role of κ receptors in the opioid control of food intake, the present study examined the central and peripheral effects of NalBzoH upon food intake. Central administration of NalBzoH (1-20 μg, i.c.v.) significantly increased food intake for up to 12 h, but failed to alter intake or body weight after 24 or 48 . The 12 h duration of NalBzoH-mediated effects may be due to either persistent κ3 receptor occupancy, and/or activation of an ingestive system which maintains its activity. Peripheral administration of NalBzoH (20 mg/kg, s.c.) significantly increased food intake for up to 1 h. To distinguish κ1 (U50,488H) and κ3 (NalBzoH) hyperphagic effects, these agonist effects were compared following pretreatment with either naltrexone or the κ1 antagonist, nor-binaltorphamine (Nor-BNI). Whereas naltrexone significantly reduced both U50,448H and NalBzoH hyperphagia, Nor-BNI blocked U50,448H, but not NalBzoH hyperphagia. These data indicate a distinct role for the κ3 receptor in ingestive behavior separable from thatof κ1 effects. © 1992. |
| Keywords: |
controlled study; nonhuman; comparative study; animal; animal experiment; feeding behavior; dose-response relationship, drug; food intake; rat; reference values; rats; analgesics; rats, wistar; infusions, parenteral; naloxone; naltrexone; pyrrolidines; cerebral ventricles; receptor subtype; 3,4 dichloro n methyl n [2 (1 pyrrolidinyl)cyclohexyl]benzeneacetamide methanesulfonate; naloxone benzoylhydrazone; kappa opiate receptor; subcutaneous drug administration; intracerebroventricular drug administration; nor-binaltorphamine; norbinaltorphimine; male; priority journal; article; receptors, opioid, kappa; support, u.s. gov't, p.h.s.; 3,4-dichloro-n-methyl-n-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-isomer; u50,488h; κ3 opioid receptor
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