Application of real-time confocal microscopy to intracellular calcium ion dynamics in rat arterioles.
The regulation of cytosolic Ca(2+) homeostasis is essential for cells, including vascular smooth muscle cells. Arterial tone, which underlies the maintenance of peripheral resistance in the circulation, is a major contributor to the control of blood pressure. Confocal microscopy was employed to study the alteration in intracellular calcium ion concentration ([Ca(2+)](i)) in arterioles (external diameters <100 microm) with respect to selected modifying reagents. 5-Hydroxytryptamine (1 microM), ATP (10 microM), and endothelin 1-3 (5 nM) elicited an increase in [Ca(2+)](i) in most arteriole smooth muscle cells. The [Ca(2+)](i) increase sometimes propagated in an intercellular manner. When noradrenaline (10 microM) was used as a stimulant, [Ca(2+)](i) increase was observed only in a portion of the smooth muscle cells. It was also noted that the reaction of these cells with respect to ATP is different between testis and brain arterioles; the [Ca(2+)](i) increase in testicular arterioles is dependent on Ca(2+) influx from extracellular space, whereas in cerebral arterioles it plays a role in both the influx of extracellular Ca(2+) and the release of Ca(2+) from intracellular stores (i.e., sarco/endoplasmic reticulum). These results indicate that arterioles in different tissues may differ greatly in their responses. Real-time confocal microscopy was found to be a useful tool for investigating the structural and functional changes in living tissues.
Saino
Tomoyuki
T
Department of Histology, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan. tsaino@iwate-med.ac.jp
Matsuura
Makoto
M
Satoh
Yoh-ichi
Y
D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D001921:Brain / Q000098:blood supply; D002118:Calcium / Q000378:metabolism*; D004338:Drug Combinations; D007783:Lactones / Q000494:pharmacology; D008297:Male; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D012717:Sesquiterpenes / Q000494:pharmacology; D013737:Testis / Q000098:blood supply
D004338:Drug Combinations; D007783:Lactones; D012717:Sesquiterpenes; D012701:Serotonin; C046319:thapsigargicin; D002118:Calcium; D009638:Norepinephrine