Novel Smooth Muscle Ca-Signaling Nanodomains in Blood Pressure Regulation.

Background: Ca signals in smooth muscle cells (SMCs) contribute to vascular resistance and control blood pressure. Increased vascular resistance in hypertension has been attributed to impaired SMC Ca signaling mechanisms. In this regard, transient receptor potential vanilloid 4 (TRPV4) ion channels are a crucial Ca entry pathway in SMCs.

Endothelial pannexin 1-TRPV4 channel signaling lowers pulmonary arterial pressure in mice.

Pannexin 1 (Panx1), an ATP-efflux pathway, has been linked with inflammation in pulmonary capillaries. However, the physiological roles of endothelial Panx1 in the pulmonary vasculature are unknown. Endothelial transient receptor potential vanilloid 4 (TRPV4) channels lower pulmonary artery (PA) contractility and exogenous ATP activates endothelial TRPV4 channels.