THE ROLE OF NA+, K+, 2CL–-COTRANSPORT IN THE H2S-DEPENDENT REGULATION OF CONTRACTILE ACTIVITY OF SMOOTH MUSCLE CELLS FROM RAT PULMONARY ARTERY

Abstract

Objective . Hydrogen sulfide (H2S) is one of gasotransmitters that participate in the regulation of a large number of cellular functions. H2S can also act as a pathological link in the development of vascular diseases, in particular hypertension. Na+, K+, 2Cl–-cotransporter (NKCC) might play an important role in vascular tone increasing due to involvement of chloride currents in the depolarization of smooth muscle cell membrane. Significant differences in the regulatory mechanisms of contractile properties of the vessels of systemic and pulmonary circulation might depend on the mechanisms of NKCC. So its role as a target for H2S requires investigation. Design and methods . The changes in mechanical tension of ring segments from pulmonary artery (PA) of WKY and SHR rats under the action of the donor of H2S (L-cysteine) was studied by organ bath technique. Results . L-cysteine caused multidirectional effects on mechanical tension of PA smooth muscle cells from WKY rats precontracted with 30 mM KCl. Bumetanide (100 μM) suppressed the relaxation but not constriction of the intact and endotheliumdenuded vascular segments caused by L-cysteine. In ring segments from PA of SHR rats, L-cysteine potentiated constriction in segments with intact endothelium but caused relaxation in endothelium-denuded segments.