Inhibition of cocaine-induced sensitization by the delta-opioid receptor antagonist naltrindole.
The influence of the delta-opioid receptor antagonist naltrindole upon sensitization to the locomotor activating effects of cocaine was assessed. Activity in response to a challenge dose of cocaine (20 mg/kg, i.p.) was significantly increased in rats which had received cocaine (20 mg/kg, i.p.) once daily for 3 days as compared to those which had previously received saline. The repeated administration of naltrindole (0.3-3.0 mg/kg, s.c.) alone did not affect activity. However, in animals which had received both naltrindole and cocaine for 3 days, no sensitization to the locomotor activating effects of cocaine was observed. These data demonstrate that the selective blockade of delta-opioid receptors modifies the development of cocaine-induced sensitization and suggest an important role of delta-opioid receptor systems in modulating the development of drug-induced sensitization.
Heidbreder
C
C
Behavioral Pharmacology and Genetics Section, National Institute on Drug Abuse, Baltimore, MD 21224.
Goldberg
S R
SR
Shippenberg
T S
TS
D000818:Animals; D003042:Cocaine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*
D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D009271:Naltrexone; C055382:naltrindole; D003042:Cocaine