Premium
RELAXATION OF MESENTERIC ARTERY OF STROKE PRONE SPONTANEOUSLY HYPERTENSIVE RATS BY CALCIUM REMOVAL
Author(s) -
Sunano S.,
Shimada T.,
Moriyama K.,
Shimamura K.
Publication year - 1990
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1990.tb01340.x
Subject(s) - extracellular , contraction (grammar) , chemistry , intracellular , relaxation (psychology) , calcium , mesenteric arteries , medicine , endocrinology , spontaneously hypertensive rat , muscle relaxation , vascular smooth muscle , artery , biophysics , anatomy , smooth muscle , biochemistry , biology , blood pressure
1. The time courses of the relaxation, induced by removal of extracellular Ca 2+ , of K‐depolarized mesenteric artery preparations from stroke prone spontaneously hypertensive rats (SHRSP) and Wistar‐Kyoto rats (WKY) were compared. 2. The time course of the decline in extracellular Ca 2+ was estimated from the time course of the relaxation and the concentration‐response curve of K+‐depolarized preparations to Ca 2+ . The time course of the decline in the intracellular free Ca 2+ concentration was also estimated from the reported relation between Ca 2+ concentration and the contraction of skinned vascular smooth muscle. 3. The time course of relaxation was exponential, the curve being made up of three components. The time course was slower in preparations from SHRSP, especially the first component of the relaxation curve. 4. The time courses of the decline in the intracellular and extracellular Ca 2+ concentrations were also exponential, being made up of three components and were also slower in the preparation made from SHRSP. 5. The wall and muscle layer of the mesenteric arteries used in the present experiments were significantly thicker in the SHRSP preparations. 6. Calculation of the half relaxation time, based on the diffusion of Ca 2+ across the blood vessel wall, suggested that the slower relaxation in preparations from SHRSP is due largely to the thicker muscle layer, although differences in Ca 2+ sequestration by the smooth muscle cells may also be involved.