| Extracellular K(+)-induced hyperpolarizations and dilatations of rat coronary and cerebral arteries involve inward rectifier K(+) channels. | |
| | |
MedLine Citation:
|
PMID: 9019539 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
1. The hypothesis that inward rectifier K(+) channels are involved in the vasodilatation of small coronary and cerebral arteries (100-200 microm diameter) in response to elevated [K+]o was tested. The diameters and membrane potentials of pressurized arteries from rat were measured using a video-imaging system and conventional microelectrodes, respectively. 2. Elevation of [K+]o from 6 to 16 mM caused the membrane potential of pressurized (60 mmHg) arteries to hyperpolarize by 12-14 mV. Extracellular Ba(2+) (Ba2+(o)) blocked K(+)-induced membrane potential hyperpolarizations at concentrations (IC(50), 6 microM) that block inward rectifier K(+) currents in smooth muscle cells isolated from these arteries. 3. Elevation of [K+]o from 6 to 16 mM caused sustained dilatations of pressurized coronary and cerebral arteries with diameters increasing from 125 to 192 microm and 110 to 180 microm in coronary and cerebral arteries, respectively. Ba2+(o) blocked K(+)-induced dilatations of pressurized coronary and cerebral arteries (IC50, 3-8 microM). 4. Elevated [K+]o-induced vasodilatation was not prevented by blockers of other types of K(+) channels (1 mM 4-aminopyridine, 1 mM TEA+, and 10 mu M glibenclamide), and blockers of Na(+)-K(+)-ATPase. Elevated [K+]o-induced vasodilatation was unaffected by removal of the endothelium. 5. These findings suggest that K+(o) dilates small rat coronary and cerebral arteries through activation of inward rectifier K(+) channels. Furthermore, these results support the hypothesis that inward rectifier K(+) channels may be involved in metabolic regulation of coronary and cerebral blood flow in response to changes in [K+]o. |
| | |
Authors:
|
H J Knot; P A Zimmermann; M T Nelson |
Related Documents
:
|
4031299 - Effects of a new nonionic and a conventional ionic contrast agent on coronary sinus ion... 21084969 - Masked hypertension in untreated normotensives: difference between a work day and a lei... 415619 - Effects of nitroglycerin on cardiac function and regional blood flow distribution in co... 2413309 - Protection by carbocromene and molsidomine against arrhythmias occurring during coronar... 150799 - Endotoxin and myocardial failure: role of the myofibril and venous return. 1666019 - Haemodynamic effects of intracoronary neuropeptide y in dogs: resistance to alpha adren... 20410919 - Systolic blood pressure and mortality in prevalent haemodialysis patients in the hemo s... 20404729 - Positive end-expiratory pressure improves end-expiratory lung volume but not oxygenatio... 3227329 - Hemoconcentration by ultrafiltration during open-heart surgery. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: The Journal of physiology Volume: 492 ( Pt 2) ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 1996 Apr |
Date Detail:
|
Created Date: 1997-02-11 Completed Date: 1997-02-11 Revised Date: 2009-11-18 |
Medline Journal Info:
|
Nlm Unique ID: 0266262 Medline TA: J Physiol Country: ENGLAND |
Other Details:
|
Languages: eng Pagination: 419-30 Citation Subset: IM |
Affiliation:
|
Department of Pharmacology, University of Vermont, Colchester, VT 05446-2500, USA. knot@northpole.med.uvm.edu |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Arteries / drug effects, physiology Barium / pharmacology Cerebral Arteries / drug effects, physiology* Coronary Vessels / drug effects, physiology* Electrophysiology Endothelium, Vascular / physiology Extracellular Space / metabolism* Female Potassium / physiology* Potassium Channel Blockers Potassium Channels / physiology* Rats Rats, Sprague-Dawley Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors Vasodilation* / drug effects |
| Grant Support | |
ID/Acronym/Agency:
|
HL-44455/HL/NHLBI NIH HHS; HL-51728/HL/NHLBI NIH HHS; HL-67647/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Potassium Channel Blockers; 0/Potassium Channels; 7440-09-7/Potassium; 7440-39-3/Barium; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Functional interaction between K(ATP) channels and the Na(+)-K(+) pump in metabolically inhibited he...
Next Document: Proton sensitivity of the GABA(A) receptor is associated with the receptor subunit composition.