Nicotine disrupts ethanol-conditioned taste aversion but does not affect The simultaneous acquisition of ethanol-induced place aversion

PAUTASSI R.M.; LONEY, GREGORY C.; KAPADIA, DELNA; MEYER, PAUL J.

San Diego

Congreso; 2018 Meeting of the Research Society on Alcoholism (RSA); 2018

Research Society on Alcoholism (RSA)

Ethanol has appetitive properties that drive ethanol seeking and intake and aversive properties thatfunction as a figurative break, limiting ethanol intake. The latter effects can be measured via conditionedtaste or place aversion paradigms (CTA and CPA, respectively). Nicotine, a drug widely coconsumedwith ethanol, significantly alters ethanol-induced aversion. This could be the result of nicotinegenerally increasing the positive rewarding effects of ethanol, or could be the result of nicotinedisrupting the neural mechanisms underlying the acquisition of taste aversion learning.We analyzednicotine?s effects on a simultaneously induced ethanol-induced CPA and CTA. Adult male LongEvans rats were given nicotine (0.0 or 0.4 mg/kg, i.p.) three times before conditioning and throughoutconditioning. Four excitatory and four inhibitory (CS+ and CS-, respectively) conditioning sessionswere conducted. During CS+ days the rats were stimulated in a lickometer with a taste conditionedstimulus (NaCl, 0.1 M), which was immediately followed by the administration of 1.5 g/kg ethanol(i.p.) and a 30-min exposure to a tactile (rod or hole floors) conditioned stimuli. On CS- sessions therats were stimulated with water in the lickometer, given vehicle i.p. administration and exposed for30 min to alternative tactile stimuli. Responsiveness towards the tactile and taste stimulus wastested across three extinction trials. Animals were stimulated with a range of NaCl concentrations(0.01, 0.1, 0.2, 0.3, 0.6 and 1.0 M) during the CTA extinction trials. The results revealed that nicotinesignificantly heightened locomotor activity during conditioning and, more importantly, significantlyreduced ethanol-induced CTA during both acquisition and extinction sessions. Nicotine, however,did not significantly alter ethanol-induced CPA. The results indicate that nicotine impairs ethanolinducedtaste, but spares ethanol-induced place, aversion. This dissociation suggests that nicotinedoes not block ethanol aversion by generally increasing the positive rewarding effect of ethanol.Instead, nicotine may block ethanol-induced CTA by disrupting the neural mechanisms responsiblefor this specific type of associative learning.