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.
Janson
A M
AM
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
Hedlund
P B
PB
Hillefors
M
M
von Euler
G
G
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