Stimulation of smooth muscle cells with phenylephrine increased intracellular calcium in both smooth muscle and endothelial cells, a flux reduced by the gap junction uncoupler palmitoleic acid.
Demonstrates calcium flux from smooth muscle cells to endothelial cells via gap junctions during alpha-1 adrenergic stimulation and vasomotion in rat mesenteric arteries.
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 microl/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 alpha(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.
Schuster et al. (Thu,) reported a other. Phenylephrine (PE) and palmitoleic acid was evaluated on Intracellular calcium concentration and artery diameter. Stimulation of smooth muscle cells with phenylephrine increased intracellular calcium in both smooth muscle and endothelial cells, a flux reduced by the gap junction uncoupler palmitoleic acid.