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Evidence for a K(ATP) ion channel link in the inhibition of hypercapnic dilation of pial arterioles by 7-nitroindazole and tetrodotoxin.
- Source :
-
European journal of pharmacology [Eur J Pharmacol] 2001 Apr 13; Vol. 417 (3), pp. 203-15. - Publication Year :
- 2001
-
Abstract
- 7-Nitroindazole, an inhibitor of neuronal nitric oxide synthase, reportedly inhibits hypercapnic dilation, but tetrodotoxin, an inhibitor of neuronal transmission, reportedly does not. Thus, evidence does not uniformly support the hypothesis of a neurogenic link to the hypercapnic response. Others suggest the hypercapnic response is mediated by a K(ATP) ion channel. In the following studies, we observed that topically administered tetrodotoxin inhibited dilations produced by hypercapnia. In addition, topical tetrodotoxin and either topical or intraperitoneal 7-nitroindazole, inhibited dilations produced by the K(ATP) channel openers, cromakalim and pinacidil. Inhibition of hypercapnic dilation and inhibition of dilation by the openers of the K(ATP) channel was immediately reversed by either L-lysine or L-arginine, amino acids previously shown to facilitate opening of the channel. The data strongly supports the previous conclusion that there is a K(ATP) ion channel link in the response of pial arterioles to hypercapnia. The location of the channel is not established by these data, nor is it known whether the action of tetrodotoxin on the channel was direct or indirect.
- Subjects :
- Animals
Arginine analogs & derivatives
Arginine pharmacology
Arterioles physiology
Carbon Dioxide metabolism
Cromakalim pharmacology
Ion Channel Gating drug effects
Lysine pharmacology
Male
Nitric Oxide Synthase antagonists & inhibitors
Nitric Oxide Synthase metabolism
Nitroprusside pharmacology
Pinacidil pharmacology
Rats
Rats, Sprague-Dawley
Respiration
Vasodilation drug effects
Vasodilator Agents pharmacology
Arterioles drug effects
Hypercapnia blood
Indazoles pharmacology
Potassium Channels metabolism
Telencephalon blood supply
Telencephalon drug effects
Tetrodotoxin pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0014-2999
- Volume :
- 417
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- European journal of pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 11334852
- Full Text :
- https://doi.org/10.1016/s0014-2999(01)00899-8