naloxone ( 2.0 and 20 mg/kg ) and naltrexone ( 2.0 and 20 mg/kg ) suppressed self-stimulation only after a significant delay , in an extinction-like response decrement pattern , mimicking the effects of reductions in current intensity ( 75 % and 50 % of baseline ) .
C0027358
naloxone
C0027360
naltrexone