Effects of acute and chronic ketocyclazocine and its modulation by oxytocin or vasopressin on food intake in rats.
The effects of acute and chronic ketocyclazocine (KCZ, a kappa receptor agonist) and its interactions with oxytocin (OXY) or vasopressin (AVP) were investigated on food intake in free-fed rats. Acute treatment with KCZ (1 mg/kg) produced a generalized hyperphagia during the light phase (0-6 h) without influencing dark phase (6-24 h) food intake. On chronic administration, tolerance developed to hyperphagic effect during light phase, whereas an enhancement in the food intake was seen during dark phase. OXY or AVP (both at 10 micrograms/kg) per se, did not affect the food intake response during either the light or the dark phase, after acute as well as chronic treatment. In the interaction studies, acute AVP or OXY attenuated the hyperphagia of KCZ during the light phase. On chronic treatment, both AVP and OXY blocked (a) the tolerance, and (b) the "reverse tolerance" to the food intake response to KCZ during light and dark phases, respectively. These results are discussed in light of complex opioid-OXY/AVP interactions during food intake in rats.
Gulati
K
K
Department of Pharmacology, University College of Medical Sciences, Delhi, India.
Ray
A
A
Sharma
K K
KK
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D004361:Drug Tolerance; D004435:Eating / Q000187:drug effects*; D016314:Ethylketocyclazocine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008027:Light; D008297:Male; D010121:Oxytocin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D017473:Receptors, Opioid, kappa; D013997:Time Factors; D014667:Vasopressins / Q000494:pharmacology*
D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D014667:Vasopressins; D001127:Arginine Vasopressin; D010121:Oxytocin; D016314:Ethylketocyclazocine; C012395:ketazocine