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Title: Possible involvement of ATP-sensitive K+ channels in the relaxant response of dog middle cerebral artery to cromakalim

Abstract

To determine the functions of ATP-sensitive K+ (KATP) channels in cerebral arterial smooth muscle, the effects of cromakalim, an opener of these channels, on tension and 86Rb efflux were investigated in endothelium-removed strips of dog middle cerebral arteries (MCAs). Cromakalim relaxed the strips that were precontracted with 20.9 mM K+ with a small maximum response. The relaxant responses to cromakalim were competitively antagonized by glibenclamide, a blocker of KATP channels. In strips precontracted with 65.9 mM K+, cromakalim failed to relax the strips. The addition of cromakalim to a resting strip caused a dose-dependent relaxation. In the resting strips of MCAs preloaded with 86Rb, cromakalim did not increase the 86Rb efflux. With 42K as the tracer ion, cromakalim still had no effect on the efflux from the resting strips. On the other hand, cromakalim increased the 86Rb and 42K efflux from the strips of dog coronary arteries (CAs). In 20.9 mM K(+)-contracted strips of MCAs, cromakalim significantly decreased the 86Rb efflux. However, after the inactivation of Ca(++)-activated K+ channels by the addition of 1 x 10(-7) M nifedipine to the 20.9 mM K(+)-contracted strips of MCAs, cromakalim produced a small but significant increase in the 86Rb efflux. Similarly, when themore » resting strips of MCAs were placed in the Ca(++)-free 12 mM-Mg(+)+ solution, cromakalim increased the 86Rb efflux. In 65.9 mM K(+)-contracted strips, cromakalim increased the 86Rb efflux from both arteries. However, the extent of the increase in 86Rb efflux was significantly smaller in the MCA than in the CA.« less

Authors:
; ; ; ;  [1]
  1. Nagoya City Univ. Medical School (Japan)
Publication Date:
OSTI Identifier:
6072752
Resource Type:
Journal Article
Journal Name:
Journal of Pharmacology and Experimental Therapeutics; (USA)
Additional Journal Information:
Journal Volume: 255:2; Journal ID: ISSN 0022-3565
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CELL MEMBRANES; PERMEABILITY; POTASSIUM COMPOUNDS; MEMBRANE TRANSPORT; VASODILATORS; BIOLOGICAL EFFECTS; ARTERIES; ATP; CEREBRAL CORTEX; DOGS; DOSE-RESPONSE RELATIONSHIPS; ENDOTHELIUM; MUSCLES; PORINS; POTASSIUM 42; RUBIDIUM 86; TRACER TECHNIQUES; ALKALI METAL COMPOUNDS; ALKALI METAL ISOTOPES; ANIMAL TISSUES; ANIMALS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BLOOD VESSELS; BODY; BRAIN; CARDIOVASCULAR AGENTS; CARDIOVASCULAR SYSTEM; CELL CONSTITUENTS; CENTRAL NERVOUS SYSTEM; CEREBRUM; DAYS LIVING RADIOISOTOPES; DRUGS; HOURS LIVING RADIOISOTOPES; INTERMEDIATE MASS NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; MAMMALS; MEMBRANE PROTEINS; MEMBRANES; MINUTES LIVING RADIOISOTOPES; NERVOUS SYSTEM; NUCLEI; NUCLEOTIDES; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANS; POTASSIUM ISOTOPES; PROTEINS; RADIOISOTOPES; RUBIDIUM ISOTOPES; TISSUES; VERTEBRATES; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Masuzawa, K, Asano, M, Matsuda, T, Imaizumi, Y, and Watanabe, M. Possible involvement of ATP-sensitive K+ channels in the relaxant response of dog middle cerebral artery to cromakalim. United States: N. p., 1990. Web.
Masuzawa, K, Asano, M, Matsuda, T, Imaizumi, Y, & Watanabe, M. Possible involvement of ATP-sensitive K+ channels in the relaxant response of dog middle cerebral artery to cromakalim. United States.
Masuzawa, K, Asano, M, Matsuda, T, Imaizumi, Y, and Watanabe, M. 1990. "Possible involvement of ATP-sensitive K+ channels in the relaxant response of dog middle cerebral artery to cromakalim". United States.
@article{osti_6072752,
title = {Possible involvement of ATP-sensitive K+ channels in the relaxant response of dog middle cerebral artery to cromakalim},
author = {Masuzawa, K and Asano, M and Matsuda, T and Imaizumi, Y and Watanabe, M},
abstractNote = {To determine the functions of ATP-sensitive K+ (KATP) channels in cerebral arterial smooth muscle, the effects of cromakalim, an opener of these channels, on tension and 86Rb efflux were investigated in endothelium-removed strips of dog middle cerebral arteries (MCAs). Cromakalim relaxed the strips that were precontracted with 20.9 mM K+ with a small maximum response. The relaxant responses to cromakalim were competitively antagonized by glibenclamide, a blocker of KATP channels. In strips precontracted with 65.9 mM K+, cromakalim failed to relax the strips. The addition of cromakalim to a resting strip caused a dose-dependent relaxation. In the resting strips of MCAs preloaded with 86Rb, cromakalim did not increase the 86Rb efflux. With 42K as the tracer ion, cromakalim still had no effect on the efflux from the resting strips. On the other hand, cromakalim increased the 86Rb and 42K efflux from the strips of dog coronary arteries (CAs). In 20.9 mM K(+)-contracted strips of MCAs, cromakalim significantly decreased the 86Rb efflux. However, after the inactivation of Ca(++)-activated K+ channels by the addition of 1 x 10(-7) M nifedipine to the 20.9 mM K(+)-contracted strips of MCAs, cromakalim produced a small but significant increase in the 86Rb efflux. Similarly, when the resting strips of MCAs were placed in the Ca(++)-free 12 mM-Mg(+)+ solution, cromakalim increased the 86Rb efflux. In 65.9 mM K(+)-contracted strips, cromakalim increased the 86Rb efflux from both arteries. However, the extent of the increase in 86Rb efflux was significantly smaller in the MCA than in the CA.},
doi = {},
url = {https://www.osti.gov/biblio/6072752}, journal = {Journal of Pharmacology and Experimental Therapeutics; (USA)},
issn = {0022-3565},
number = ,
volume = 255:2,
place = {United States},
year = {Thu Nov 01 00:00:00 EST 1990},
month = {Thu Nov 01 00:00:00 EST 1990}
}