Role of dihydropyridine-sensitive calcium channels in the regulation of norepinephrine release in hypertension.
In the present study, in order to elucidate the role of dihydropyridine (DHP)-sensitive calcium (Ca) channels in the regulation of neurotransmitter release in hypertension, we examined the effects of the DHP-sensitive Ca channel blocker nicardipine on norepinephrine (NE) release in blood vessels of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. The stimulation-evoked pressor responses and NE release were significantly greater in the mesenteric arteries of SHR than in the mesenteric arteries of WKY rats. Nicardipine significantly inhibited the stimulation-evoked NE release as well as vasoconstrictor responses in the mesenteric arteries to a greater extent in SHR than in WKY rats. These results demonstrated that nicardipine markedly reduced the stimulation-evoked NE release in blood vessels of SHR, which might suggest that the DHP-sensitive Ca channels could be involved, at least in part, in the regulation of NE release in hypertension.
Tsuda
K
K
Department of Medicine, Wakayama Medical University, Japan. tsudak@mail.wakayama-med.ac.jp
Tsuda
S
S
Nishio
I
I
Masuyama
Y
Y
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology*; D004095:Dihydropyridines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism; D009529:Nicardipine / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; C038806:1,4-dihydropyridine; D009529:Nicardipine; D009638:Norepinephrine