Effect of chronic (-)-nicotine treatment on rat cerebral benzodiazepine receptors.
The purpose of this study was to clarify the effect of (-)-nicotine on cerebral benzodiazepine receptors (BzR) with radiotracer methods. The effect of (-)-nicotine on BzR was examined in in vitro studies using chronic (-)-nicotine-treated rats using 3H-diazepam. The in vitro radioreceptor assay showed a 14% increase in the maximum number of binding sites of BzR in chronic (-)-nicotine-treated rats in comparison with the control rats. Moreover, a convenient in vivo uptake index of 125I-iomazenil was calculated and a higher uptake of the radioactivity was observed in the chronic (-)-nicotine-treated group than in the control group. Although further studies of the mechanism of (-)-nicotine on such BzR changes are required, an increase in the amount of BzR in the cerebral cortex was found in rats that underwent chronic (-)-nicotine treatment, and this result contributed to the understanding of the effects of (-)-nicotine and smoking on neural functions.
Magata
Y
Y
Department of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine, Kyoto University, Japan. magata@kuhp.kyoto-u.ac.jp
Kitano
H
H
Shiozaki
T
T
Iida
Y
Y
Nishizawa
S
S
Saji
H
H
Konishi
J
J
D000818:Animals; D000927:Anticonvulsants / Q000378:metabolism; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D003975:Diazepam / Q000378:metabolism; D005442:Flumazenil / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D011877:Radionuclide Imaging; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism; D014018:Tissue Distribution
D000927:Anticonvulsants; D007457:Iodine Radioisotopes; D018722:Nicotinic Agonists; D011963:Receptors, GABA-A; D005442:Flumazenil; D009538:Nicotine; C063038:iomazenil; D003975:Diazepam