Nicotine-induced sensitization to ambulatory stimulant effect produced by daily administration into the ventral tegmental area and the nucleus accumbens in rats.
Bilateral injections of nicotine (30 micrograms/side) into the ventral tegmental area (VTA) and the nucleus accumbens (NACC) increased the ambulatory activity in rats. Moreover, daily injections of nicotine (10, 20 and 30 micrograms/side) into the VTA and the NACC for 6 successive days produced sensitization to the ambulatory stimulant effect of nicotine. Sensitization produced by daily injections of nicotine (20 micrograms/side) into both the sites was maintained for withdrawal periods of 10 days. Mecamylamine (2 mg/kg, i.p.), SCH23390 (0.05 mg/kg, i.p.) and spiperone (0.1 mg/kg, i.p.) antagonized nicotine-induced sensitization to the ambulatory stimulant nicotine-induced sensitization to the ambulatory stimulant effect produced by daily injections into the VTA. These results suggest that nicotine-induced sensitization to the ambulatory stimulant effect involves the stimulation of the mesolimbic dopaminergic pathway through the nicotinic acetylcholine receptor (nAChR) in the VTA and the NACC.
Kita
T
T
Department of Pharmacology, Nara Medical University, Kashihara, Japan.
Okamoto
M
M
Nakashima
T
T
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000276:immunology; D013134:Spiperone / Q000494:pharmacology; D013681:Tegmentum Mesencephali / Q000187:drug effects*
D001552:Benzazepines; D011978:Receptors, Nicotinic; D013134:Spiperone; D008464:Mecamylamine; D009538:Nicotine