Extended blockade of the discriminative stimulus effects of nicotine with low doses of ethanol.
The aim of the present study was to further evaluate effects of ethanol on nicotine discrimination and to correlate these effects with blood ethanol levels. Rats were trained to discriminate 0.3 mg/kg nicotine from its vehicle in the standard two-lever operant procedure. In antagonism tests, small doses of ethanol (0.25-0.5 g/kg) were injected either 5 or 50 min before nicotine. Both doses of ethanol partially antagonized the nicotine cue regardless of the pre-treatment time. Ethanol attenuated also inhibitory effects of nicotine on the rate of responding. Suppression of the cueing effects of nicotine was noted even 60 min after the injection of 0.25 g/kg ethanol, i.e. at the time point when the blood ethanol level was close to zero. Ethanol-induced antagonism of the nicotine cue disappeared when longer time (110 min) was allowed to elapse between the ethanol (0.5 g/kg) and nicotine injection. Concluding, the present results may indicate that the effects of ethanol on nicotine discrimination are not primarily related to blood ethanol levels.
Korkosz
Agnieszka
A
Department of Pharmacology, Institute of Psychiatry and Neurology, 9 Sobieskiego St., PL-02957, Warsaw, Poland.
Taracha
Ewa
E
Plaznik
Adam
A
Wrobel
Elzbieta
E
Kostowski
Wojciech
W
Bienkowski
Przemyslaw
P
D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology; D003463:Cues; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005731:Ganglionic Stimulants / Q000494:pharmacology; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D002492:Central Nervous System Depressants; D005731:Ganglionic Stimulants; D000431:Ethanol; D009538:Nicotine