Evidence for signaling via gap junctions from smooth muscle to endothelial cells in rat mesenteric arteries: possible implication of a second messenger.

We investigated heterocellular communication in rat mesenteric arterial strips at the cellular level using confocal microscopy. To visualize Ca(2+) changes in different cell populations, smooth muscle cells (SMCs) were loaded with Fluo-4 and endothelial cells (ECs) with Fura red. SMC contraction was stimulated using high K(+) solution and Phenylephrine.

Ca2+ dynamics in a population of smooth muscle cells: modeling the recruitment and synchronization.

Many experimental studies have shown that arterial smooth muscle cells respond with cytosolic calcium rises to vasoconstrictor stimulation. A low vasoconstrictor concentration gives rise to asynchronous spikes in the calcium concentration in a few cells (asynchronous flashing). With a greater vasoconstrictor concentration, the number of smooth muscle cells responding in this way increases (recruitment) and calcium oscillations may appear.

Calcium dynamics and vasomotion in rat mesenteric arteries.

Smooth muscle cell calcium dynamics and diameter were measured in intact pressurized rat mesenteric artery segments during vasoconstriction and vasomotion. Arteries showed a certain norepinephrine (NE) threshold (0.3-0.

Recruitment of smooth muscle cells and arterial vasomotion.

Investigating the recruitment and synchronization of smooth muscle cells (SMCs) is the key to understanding the physical mechanisms leading to contraction and spontaneous diameter oscillations of arteries, called vasomotion. We improved a method that allows the correlation of calcium oscillations (flashing) of individual SMCs with mean calcium variations and arterial contraction using confocal microscopy. Endothelium-stripped rat mesenteric arteries were cut open, loaded with dual calcium fluorescence probes, and stimulated by increasing concentrations of the vasoconstrictors phenylephrine (PE) and KCl.

Role of membrane potential in vasomotion of isolated pressurized rat arteries.

Vasomotion, the phenomenon of vessel diameter oscillation, regulates blood flow and resistance. The main parameters implicated in vasomotion are particularly the membrane potential and the cytosolic free calcium in smooth muscle cells. In this study, these parameters were measured in rat perfused-pressurized mesenteric artery segments.