Acidosis Dilates Brain Parenchymal Arterioles by Conversion of Calcium Waves to Sparks to Activate BK Channels
- 20 January 2012
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Circulation Research
- Vol. 110 (2), 285-294
- https://doi.org/10.1161/circresaha.111.258145
Abstract
Rationale:Acidosis is a powerful vasodilator signal in the brain circulation. However, the mechanisms by which this response occurs are not well understood, particularly in the cerebral microcirculation. One important mechanism to dilate cerebral (pial) arteries is by activation of large-conductance, calcium-sensitive potassium (BKCa) channels by local Ca2+ signals (Ca2+ sparks) through ryanodine receptors (RyRs). However, the role of this pathway in the brain microcirculation is not known. Objective:The objectives of this study were to determine the mechanism by which acidosis dilates brain parenchymal arterioles (PAs) and to elucidate the roles of RyRs and BKCa channels in this response. Methods and Results:Internal diameter and vascular smooth muscle cell Ca2+ signals were measured in isolated pressurized murine PAs, using imaging techniques. In physiological pH (7.4), vascular smooth muscle cells exhibited primarily RyR-dependent Ca2+ waves. Reducing external pH from 7.4 to 7.0 in both normocapnic and...Keywords
This publication has 53 references indexed in Scilit:
- Fundamental increase in pressure-dependent constriction of brain parenchymal arterioles from subarachnoid hemorrhage model rats due to membrane depolarizationAmerican Journal of Physiology-Heart and Circulatory Physiology, 2011
- Endothelial SKCa and IKCa Channels Regulate Brain Parenchymal Arteriolar Diameter and Cortical Cerebral Blood FlowJournal of Cerebral Blood Flow & Metabolism, 2010
- Pericytes in capillaries are contractile in vivo, but arterioles mediate functional hyperemia in the mouse brainProceedings of the National Academy of Sciences of the United States of America, 2010
- Subtype identification and functional characterization of ryanodine receptors in rat cerebral artery myocytesAmerican Journal of Physiology-Cell Physiology, 2010
- Astrocytic endfoot Ca 2+ and BK channels determine both arteriolar dilation and constrictionProceedings of the National Academy of Sciences of the United States of America, 2010
- SK Ca and IK Ca Channels, Myogenic Tone, and Vasodilator Responses in Middle Cerebral Arteries and Parenchymal ArteriolesStroke, 2009
- Overactive Bladder and Incontinence in the Absence of the BK Large Conductance Ca2+-activated K+ ChannelJournal of Biological Chemistry, 2004
- Mechanism of Extracellular K + -Induced Local and Conducted Responses in Cerebral Penetrating ArteriolesStroke, 2002
- Reduced Ca2+-induced Ca2+ release from skeletal muscle sarcoplasmic reticulum at low pHCanadian Journal of Physiology and Pharmacology, 1992
- Analysis of vasoactivity of local pH, PCO2 and bicarbonate on pial vessels.Stroke, 1977