Vascular Tone and Ca2+ Signaling in Murine Cremaster Muscle Arterioles In Vivo. (10th April 2013)

• Record Type: Journal Article
• Authors: Mauban, Joseph R.H.; Zacharia, Joseph; Zhang, Jin; Wier, Withrow Gil
• Is Part Of: Microcirculation. Volume 20:Number 3(2013:Apr.)
• Page Start: 269
• Page End: 277
• Publication Date: 2013-04-10
• Subjects: Biological transport -- Periodicals; Microcirculation -- Physiology -- Periodicals; 612.135
• DOI: 10.1111/micc.12025
• Languages: English
• ISSNs: 1073-9688

Abstract

<abstract abstract-type="main" xml:lang="en" id="micc12025-abs-0001"> <title>Abstract</title> <sec id="micc12025-sec-0001" sec-type="section"> <title>Objectives</title> <p>We sought to determine some of the molecular requirements for basal state "tone" of skeletal muscle arterioles <italic>in vivo</italic>, and whether asynchronous Ca<sup>2+</sup> waves are involved or not.</p> </sec> <sec id="micc12025-sec-0002" sec-type="section"> <title>Methods</title> <p>Cremaster muscles of anesthetized exMLCK and smGCaMP2 biosensor mice were exteriorized, and the fluorescent arterioles were visualized with wide‐field, confocal or multiphoton microscopy to observe Ca<sup>2+</sup> signaling and arteriolar diameter.</p> </sec> <sec id="micc12025-sec-0003" sec-type="section"> <title>Results</title> <p>Basal state tone of the arterioles was ~50%. Local block of Ang‐II receptors (AT<sub>1</sub>) or α<sub>1</sub>‐adrenoceptors (α<sub>1</sub>‐AR) had no effect on diameter, nor did complete block of sympathetic nerve activity (SNA). Inhibition of phospholipase C caused dilation nearly to the Ca<sup>2+</sup>‐free (passive) diameter, as did exposure to nifedipine or 2‐APB. Arterioles were also dilated when treated with SKF96365. High‐resolution imaging of exMLCK fluorescence (ratio) or GCaMP2 fluorescence in smooth muscle cells failed to reveal Ca<sup>2+</sup> waves (although Ca<sup>2+</sup> waves/transients were readily detected by both biosensors in small arteries, <italic>ex vivo</italic>).</p> </sec> <sec id="micc12025-sec-0004" sec-type="section"> <title>Conclusions</title> <p>Arterioles of cremaster muscle have vascular tone of ~ 50%, which is not due to α<sub>1</sub>‐AR, AT<sub>1</sub>R, or SNA. PLC activity, L‐type Ca<sup>2+</sup> channels, 2‐APB‐ and SKF96365‐sensitive channels are required. Propagating Ca<sup>2+</sup> waves are not present. A key role for PLC and InsP<sub>3</sub>R in vascular tone <italic>in vivo</italic>, other than producing Ca<sup>2+</sup> waves, is suggested.</p> </sec> </abstract>