ИССЛЕДОВАНИЕ РОЛИ NA+, K+, 2CL- - КОТРАНСПОРТА В РЕГУЛЯЦИИ ТОНУСА ЛЕГОЧНОЙ АРТЕРИИ

Abstract

Purpose. We studied the role of Na+, K+, 2Cl- cotransport (NKCC) in contractile activity of pulmonary artery seg- ments with intact endothelium induced by incubation in nonisosmotic solutions. Materials and methods. The influence of nonisosmotic solutions and blocker of NKCC on vascular segments mechanical tension was studied in isometric regime with organ bath technique performed with the 4-channel Myobath II and software complex LAB-TRAX-4/16 (Germany). Hyperosmotic shrinkage was induced by adding 50-300 mM su- crose to the Krebs solution, the hypoosmotic environment was created by reducing the concentration of NaCl from 70 mM to 40 mM. Bumetanide was used as an NKCC blocker. The amplitude of the contractile responses was evaluated as a percentage of the control contraction in highpotassium solution. Results. The addition of 50-300 mM sucrose to the Krebs incubation solution caused a development of dose- dependent of sustained contractile responses. The amplitude of hyperosmotic striction increased with inhibition of NKCC. Incubation of segments in hypoosmotic solution caused the development of transient contractile responses, the amplitude of which decreased in the presence of NKCC inhibitor. Conclusion. Iincubation of pulmonary artery vascular segments in hyper- and hyposmotic solutions induces con- tractile responses, the amplitude of which depends on the NKCC activity.