Chronic nicotine treatment decreases dopamine D2 agonist binding in the rat basal ganglia.
To elucidate possible actions of nicotine on dopamine D2 receptor binding, the effect of chronic continuous (-)nicotine treatment (osmotic pumps s.c., 0.125 mg kg h-2, 14 days) was studied in the binding of [3H]N-propylnorapomorphine ([3H]NPA) and [125I]sulpride in coronal cryostat sections in the rat. Quantitative autoradiography showed that nicotine decreased the binding of [3H]NPA in the basal ganglia, preferentially in the nucleus accumbens and olfactory tubercle. In contrast, [125I]sulpride binding was not affected. Nicotine decreased the KD value of [3H]NPA by 27% and decreased the Bmax value by 17%, using filter-wiped sections. These results indicate that chronic continuous nicotine treatment affects the D2 receptor and that this effect may be involved in the development of nicotine dependence.
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
A M
AM
Janson
P B
PB
Hedlund
M
M
Hillefors
G
G
von Euler
D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives / Q000494:pharmacology; D001345:Autoradiography; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D016548:Prosencephalon / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism*; D013469:Sulpiride / Q000494:pharmacology
D015259:Dopamine Agents; D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; C009074:N-n-propylnorapomorphine; D009538:Nicotine; D013469:Sulpiride; D001058:Apomorphine