Cytosolic-free calcium in smooth-muscle and endothelial cells in an intact arterial wall from rat mesenteric artery in vitro.
The regulation of cytosolic-free calcium concentration of smooth-muscle and endothelial cells was mainly studied on cultured cells where the cross talk between these two coupled cell types is lost. In the present study, the cytosolic-free calcium concentration in the endothelial and the smooth-muscle cells was examined in an intact arterial wall in vitro. Strips of the main branch of rat mesenteric artery were used. Cytosolic-free calcium concentration [Ca2+]i was estimated by determining the fluorescence ratio of the two calcium probes, Fluo-4 and Fura red. The emitted fluorescence of both probes was measured with a confocal microscope. We showed that potassium and phenylephrine, which increase the cytosolic -free calcium concentration of the smooth-muscle cells, also indirectly influence the calcium concentration in the endothelial cells. By simultaneously determining [Ca2+]i in the endothelial and the smooth-muscle cells of an arterial strip, we observed that when calcium increases in the endothelial cells in response to acetylcholine, it slightly decreases in the smooth-muscle cells. We conclude that the regulation of [Ca2+]i in the arterial endothelial cell, depends according to the stimuli either upon the endothelial cells themselves, or upon the coupled smooth-muscle cells.
Oishi
H
H
Department of Zoology and Animal Biology, University of Geneva, Sciences III, Geneva, Switzerland.
Budel
S
S
Schuster
A
A
Stergiopulos
N
N
Meister
J J
JJ
Bény
J L
JL
D000109:Acetylcholine / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000814:Aniline Compounds / Q000032:analysis; D000818:Animals; D001572:Benzofurans / Q000032:analysis; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000032:analysis; D007093:Imidazoles / Q000032:analysis; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology; D014966:Xanthenes / Q000032:analysis
D000316:Adrenergic alpha-Agonists; D000814:Aniline Compounds; D001572:Benzofurans; C409648:Fluo 4; D005456:Fluorescent Dyes; D007093:Imidazoles; D014665:Vasodilator Agents; D014966:Xanthenes; C082877:fura red; D010656:Phenylephrine; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium