Isradipine attenuates the ischemia-induced release of dopamine in the striatum of the rat.
We examined the effect of isradipine, a blocker of L-type voltage-sensitive Ca2+ channels (VSCCs), on the ischemia-induced release of dopamine in the rat striatum. Perfusion of 200 micrograms/ml isradipine in the striatum did not alter extracellular dopamine concentrations monitored by microdialysis. However, a marked increase (145-fold) in dopamine level during forebrain ischemia, developed by bilateral carotid artery occlusion, was attenuated significantly by 37% by isradipine whereas the intensity of ischemia, monitored by striatal blood flow, was unchanged. These results suggest that isradipine attenuates the ischemia-induced release of dopamine via blockade of L-type VSCCs on dopaminergic neurons.
Ooboshi
H
H
Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Sadoshima
S
S
Ibayashi
S
S
Yao
H
H
Uchimura
H
H
Fujishima
M
M
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001784:Blood Gas Analysis; D002545:Brain Ischemia / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007267:Injections; D017275:Isradipine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D017275:Isradipine