Nicotine releases stereoselectively and Ca2(+)-dependently endogenous 3,4-dihydroxyphenylalanine from rat striatal slices.
In superfused slices of rat striatum, nicotine-evoked release of endogenous 3,4-dihydroxyphenylalanine (DOPA) was studied in comparison with that of dopamine (DA). (+/-)-Nicotine (0.1-10 microM) constantly and repetitively released DOPA and DA over a similar time course in a concentration-dependent manner. The ratio of DOPA and DA evoked was approximately 1:2-3. The turnover rate of DOPA was about 300 times higher compared to DA. (+/-)-Nicotine (10 microM)-induced DOPA release was mecamylamine (20 microM)-sensitive, Ca2(+)-dependent and tetrodotoxin (0.3 microM)-insensitive. The (+)-isomer induced no DOPA release. These characteristics of DOPA release were almost the same as those of DA. Nicotine evokes endogenous DOPA via nicotinic cholinergic receptors in a manner similar to the transmitter DA. These findings further support a probable role of DOPA as a neuroactive substance in the rat central nervous system.
Misu
Y
Y
Department of Pharmacology, Yokohama City University School of Medicine, Japan.
Goshima
Y
Y
Nakamura
S
S
Kubo
T
T
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology
D013779:Tetrodotoxin; D004533:Egtazic Acid; D004295:Dihydroxyphenylalanine; D008464:Mecamylamine; D009538:Nicotine; D002118:Calcium; D004298:Dopamine