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Intravascular Pressure Activates Ryanodine Receptors and Elicits Calcium Waves in Cerebral Arterial Smooth Muscle Cells.
Author(s) -
Brett Suzanne E,
Bradley Karen N,
Welsh Donald G
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.965.9
Subject(s) - ryanodine receptor , cerebral arteries , myograph , cerebral circulation , vascular smooth muscle , vasoconstriction , chemistry , medicine , biophysics , calcium , cardiology , anatomy , endothelium , smooth muscle , biology
The study examined the effects of intravascular pressure on Ca 2+ wave generation in cerebral arterial smooth muscle cells. Rat cerebral arteries stripped of endothelium and loaded with fluo‐4 were mounted in a pressure myograph. Ca 2+ waves were monitored with a spinning disk confocal microscope coupled to an ICCD that captured images at a rate of 10 frames per second. Elevating intravascular pressure (15 to 80 mmHg) increased Ca 2+ wave frequency (0.56±0.3 to 8.47±0.5 events min −1 ) and the proportion of firing cells (6.98±2.9 to 66.43±8.7%). The generation and maintenance of these asynchronous events was largely voltage‐independent since Diltiazem (30 μM; L‐type Ca 2+ channel blocker) application and manipulations of resting membrane potential had only a limited effect on pressure‐induced Ca 2+ waves. Ryanodine (50 μM) application blocked Ca 2+ wave generation in cerebral arterial smooth muscle cells and attenuated pressure‐induced vasoconstriction. In closing, mechanical stimuli are capable of activating ryanodine receptors and augmenting the generation of Ca 2+ waves in a manner that is independent of resting membrane potential. While Ca 2+ waves are asynchronous among neighboring smooth muscle cells, their generation contributes to the maintenance of myogenic tone in the cerebral circulation. Supported by the Natural Science and Engineering Research Council of Canada.