Peripheral involvement in nicotine-induced enhancement of ethanol intake.
It is a well-known fact that a large percentage of alcoholics smoke, and in the experimental rat, intermittent nicotine administration enhances ethanol intake and ethanol preference in a free-choice situation between 6% (v/v) ethanol and water. The present study focuses on the possible involvement of central and/or peripheral nicotine acetylcholine receptors (nAChR) in nicotine-induced sensitization to dopamine-related behavioral effects of ethanol. Wistar rats drinking less than 60% of their total daily fluid from a 6% ethanol solution were used in the study. Nicotine, vehicle, mecamylamine, hexamethonium, mecamylamine+nicotine, and hexamethonium+nicotine were administered subchronically for 15 days. All groups, except the vehicle pre-treated group, markedly increased their ethanol preference to approximately 80%, as well as their ethanol intake. NMRI mice received the same treatments for 10 days, after which ethanol (2.5 g/kg, intraperitoneal (i.p.)) was given acutely and locomotor activity was recorded. Ethanol-induced locomotor stimulation was enhanced in most groups, as compared to the vehicle pre-treated group. Administration of quarternary autonomic drugs to ethanol high-preferring rats (hexamethonium, methscopolamine, sotalol and phentolamine) according to different acute and chronic treatment protocols indicated that the enhanced ethanol intake may involve increased ganglionic and/or peripheral muscarinic neurotransmission. Taken together, the above results indicate that peripheral mechanisms may be involved in the enhancement of dopamine-related behavioral effects of ethanol observed after subchronic intermittent treatment with nicotinic drugs.
Ericson
M
M
Department of Pharmacology, Institute of Physiology and Pharmacology, Göteborg University, Sweden.
Engel
J A
JA
Söderpalm
B
B
D000428:Alcohol Drinking; D000818:Animals; D004326:Drinking / Q000187:drug effects; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000502:physiology
D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D009538:Nicotine