These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mechanical responses of isolated dog cerebral arteries to reduction of external K, Na, and Cl.
    Author: Toda N.
    Journal: Am J Physiol; 1978 Apr; 234(4):H404-11. PubMed ID: 645879.
    Abstract:
    Reduction of the extracellular potassium concentration ([K+]0) caused a significant contraction in helical strips of dog cerebral arteries, but only a slight contraction, or none, in peripheral (coronary, mesenteric, renal, and femoral) arteries. The cerebroarterial contraction was abolished by treatment with ouabain or by substitution of Li+ for Na+, and suppressed by exposure to Ca2+-free media or verapamil. When one-half of the NaCl of the bathing solution was substituted with choline chloride a moderate, sustained contraction was produced in cerebral and peripheral arteries. Ouabain potentiated this contraction, whereas exposure to Ca2+-free media abolished it. Substitution of Na propionate, NaI, or Na acetylglycinate for one-half of the NaCl elicited a marked, transient contraction in only the cerebral arteries. This contractile response was potentiated by ouabain and markedly attenuated by exposure to Ca2+-free media. It may thus be concluded that cerebroarterial contractions induced by a reduction in [K+]0 are due to inhibition of the electrogenic Na+ pump, which results in depolarization of smooth muscle cells. Substitution of Cl- with less permeant anions appears to produce cerebroarterial contraction in association with depolarization of smooth muscle cells.
    [Abstract] [Full Text] [Related] [New Search]