Determination of exocytosis mechanisms of DOPA in rat striatum using in vivo microdialysis.
To explore the exocytosis mechanism of striatal 3,4-dihydroxyphenylalanine (DOPA), this study determined the interaction between voltage-sensitive Ca2+-channel (VSCC) and SNARE on releases of DOPA and glutamate in rat striatum using microdialysis. Inhibitors of VSCCs and SNAREs did not affect basal glutamate release but decreased basal DOPA release, however, blocking effects of P-type-VSCC and synaptobrevin inhibitors were weaker than those of N-type-VSCC and syntaxin. The K+-evoked releases of DOPA and glutamate were reduced by inhibitors of P-type-VSCC and synaptobrevin predominantly and by inhibitors of N-type-VSCC and syntaxin weakly. However, interaction study between VSCC and SNARE on K+-evoked DOPA release indicates that DOPA release is regulated by different exocytosis mechanism from glutamate and monoamine during the depolarization stage (N-type-VSCC/P-type-VSCC/synaptobrevin and/or combination with N-type-VSCC/synaptobrevin and P-type-VSCC/synaptobrevin). Therefore we conclude that striatal DOPA release might be regulated by its specific exocytosis mechanism via different from dopaminergic presynaptic vesicle.
Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8562, Japan.
Gang
G
Zhu
Motohiro
M
Okada
Shukuko
S
Yoshida
Shinichi
S
Hirose
Sunao
S
Kaneko
D000704:Analysis of Variance; D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020867:omega-Agatoxin IVA / Q000494:pharmacology; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020867:omega-Agatoxin IVA; D018698:Glutamic Acid; D004295:Dihydroxyphenylalanine; D020866:omega-Conotoxin GVIA; D001905:Botulinum Toxins; D011188:Potassium