Simultaneous arterial calcium dynamics and diameter measurements: application to myoendothelial communication

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 280; no. 3; pp. H1088 - H1096
• Main Authors: Schuster, Alexander, Oishi, Hirotaka, Beny, Jean-Louis, Stergiopulos, Nikolaos, Meister, Jean-Jacques
• Format: Journal Article
• Language: English
• Published: United States 01.03.2001
• Subjects: Animals; Calcium - metabolism; Cell Communication - physiology; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Gap Junctions - metabolism; In Vitro Techniques; Male; Mesenteric Arteries - cytology; Mesenteric Arteries - metabolism; Microscopy, Fluorescence - methods; Microscopy, Fluorescence - standards; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - metabolism; Rats; Rats, Wistar; Reproducibility of Results; Vasoconstriction - physiology
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.2001.280.3.h1088

1  Biomedical Engineering Laboratory, Swiss Federal Institute of Technology, 1015 Lausanne; and 2  Department of Zoology and Animal Biology, University of Geneva, 1211 Geneva, Switzerland The goal of the present study was to analyze the intercellular calcium communication between smooth muscle cells (SMCs) and endothelial cells (ECs) by simultaneously monitoring artery diameter and intracellular calcium concentration in a rat mesenteric arterial segment in vitro under physiological pressure (50 mmHg) and flow (50 µl/min) in a specially developed system. Intracellular calcium was expressed as the fura 2 ratio. The diameter was measured using a digital image acquisition system. Stimulation of SMCs with the 1 -agonist phenylephrine (PE) caused not only an increase in the free intracellular calcium concentration of the SMCs as expected but also in the ECs, suggesting a calcium flux from the SMCs to the ECs. The gap junction uncoupler palmitoleic acid greatly reduced this increase in calcium in the ECs on stimulation of the SMCs with PE. This indicates that the signaling pathway passes through the gap junctions. Similarly, although vasomotion originates in the SMCs, calcium oscillates in both SMCs and ECs during vasomotion, suggesting again a calcium flux from the SMCs to the ECs. smooth muscle cells; endothelial cells; calcium imaging; gap junctions; rat mesenteric artery