Dissociation of the opioid and nonopioid effects of cyclazocine.
Lower IV doses of (dl)- and (l)-cyclazocine (0.05 and 0.50 mg/kg) in the rat produced opioid EEG and behavioral effects that were antagonized by naltrexone pretreatment. Higher IV doses of (dl)- and (l)-cyclazocine (1.00 and 2.00 mg/kg) produced initial "psychotomimetic-like" behavioral effects that were naltrexone-resistant, followed by the delayed emergence of opioid EEG and behavioral effects that were naltrexone-sensitive, (d)-Cyclazocine produced only "psychotomimetic-like" behavioral effects that were naltrexone-resistant. (dl)-Cyclazocine antagonized morphine-induced EEG and behavioral effects in naive rats. (l)-Cyclazocine precipitated withdrawal symptoms in morphine-dependent rats. In contrast, (d)-cyclazocine produced "psychotomimetic-like" effects, but no withdrawal symptoms. Thus, (dl)- and (l)-cyclazocine produced dose- and time-related opioid and nonopioid "psychotomimetic-like" effects, while (d)-cyclazocine produced only nonopioid "psychotomimetic-like" effects.
Calligaro
D
D
Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore 21202.
Young
G A
GA
Khazan
N
N
D000818:Animals; D003496:Cyclazocine / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D005260:Female; D006213:Hallucinogens / Q000494:pharmacology*; D009020:Morphine / Q000037:antagonists & inhibitors; D009021:Morphine Dependence / Q000503:physiopathology; D009271:Naltrexone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism
D006213:Hallucinogens; D009294:Narcotics; D009271:Naltrexone; D009020:Morphine; D003496:Cyclazocine