Delineation of mu-antagonist, partial kappa agonist and non-opioid agonist activity of cyclazocine using urinary output of rats.
The effects of cyclazocine (SC) were studied under a variety of test conditions to determine its various activities on urinary output. Cyclazocine antagonized the morphine-induced (20 mg/kg) antidiuretic effect in water-loaded (3 ml/100 g b.wt.) rats at low doses (0.08, 0.16 and 0.32 mg/kg). At higher doses (1.25, 5 and 20 mg/kg), cyclazocine caused diuresis in normally hydrated rats. The diuresis produced by 1.25 and 5, but not 20 mg/kg, was antagonized by naloxone (10 mg/kg). In water-deprived rats and in normally hydrated rats, cyclazocine, in a dose-related fashion, antagonized the diuretic effects of 0.08 mg/kg of bremazocine. These results are compatible with the interpretation that cyclazocine has mu-antagonist activity at low doses, then partial kappa-agonist activity at intermediate doses, followed by non-opioid agonist activities at the higher doses.
D000818:Animals; D001575:Benzomorphans / Q000494:pharmacology; D003496:Cyclazocine / Q000008:administration & dosage / Q000494:pharmacology*; D004231:Diuresis / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects* / Q000502:physiology; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D014868:Water Deprivation
D001575:Benzomorphans; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D009270:Naloxone; D009020:Morphine; C027248:bremazocine; D003496:Cyclazocine