ABSTRACT
This chapter focuses on recent advancements in our understanding about the cellular and molecular properties as well as postulated function of a subset of chloride channels found in both endothelial and smooth muscle cells of the pulmonary vasculature that are sensitive to changes in osmolarity. The major aims of this review are to highlight the characteristics of these Cl currents and to discuss putative genes that are thought to encode the underlying channel protein. We denote this current as the swelling-activated Cl current or ICl(Swell). However, it should be noted that various other nomenclatures are used to describe this conductance based on their ability to be activated by cell volume changes (e.g., volume-regulated anion channel, volume-regulated anion current) or their permeability to various organic anions [volume-sensitive organic osmolyte anion channel (VSOAC)]. For the sake of clarity the main focus will be on ICl(Swell) in smooth muscle cells followed by a separate section on ICl(Swell) in pulmonary endothelial cells.
