Selective inhibition of neuronal nitric oxide synthase fails to alter the resting tension and the relaxant effect of bradykinin in isolated rat middle cerebral arteries.
The role of the neuronal isoform of the nitric oxide (NO) synthase (nNOS) in the regulation of the cerebrovascular tone was studied in vitro. Selective inhibition of nNOS by 7-nitro indazole monosodium salt (7-NINA) failed to alter the resting tension and the relaxant effect of bradykinin in isolated rat middle cerebral arteries. These results indicate that 1./ 7-NINA is selective for nNOS and 2./ cerebrovascular nNOS is involved neither in the resting NO production nor in the mediation of the relaxant effect of bradykinin. Therefore, nNOS-derived NO that contributes to the maintenance of the resting cerebral blood flow in vivo appears to be released from neurons and/or glial cells.
Benyó
Z
Z
Department of Physiology, Ludwig-Maximilians University, Munich, Germany. benyo@elet2.sote.hu
Lacza
Z
Z
Görlach
C
C
Wahl
M
M
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D007191:Indazoles / Q000494:pharmacology*; D008297:Male; D020768:Middle Cerebral Artery / Q000187:drug effects* / Q000201:enzymology; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D052248:Nitric Oxide Synthase Type I; D051381:Rats; D017208:Rats, Wistar; D014544:Uridine Triphosphate / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D004791:Enzyme Inhibitors; D007191:Indazoles; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D001920:Bradykinin; D014544:Uridine Triphosphate; C080122:7-nitroindazole