[Regulation of cardiovascular myogenic tone via G-protein-sensitive transmembrane signal pathways]

Effects of cellular hypoxia on [Ca2+]i in CK1.4 cells expressed Na(+)-Ca2+ exchange protein were determined by fura-2 fluorescence imaging. In vitro perfused of canine cardiovascular samples (37 degrees C), changes of aortic, cervical, pulmonary arterial smooth myogenic tone and cardiac papillary myogenic tone were measured by mechanic-electrical transducers via a computer-aid autosampling system. In the whole dogs, pharmacolkinetic parameters of a VISA agent at three dosages were calculated by 125Isod-1 scintillation counting according to a 6 x 6 statistical model. The results indicated that 1. hypoxia inhibited the Na(+)-Ca2+ exchange protein induced by and elevated Ca(2+)-influx and [Ca2+]i in the CK1.4 cells; 2. hypoxic perfusions depressed the AlF4-(-)activated myogenic vasoconstriction in aortic, cervical and pulmonary arteries, but facilitated the cardiac papillary myogenic contraction Ca(2+)-influx-induced, the finding was consistent with the first result; and 3. the VISA agent distributed in the cell together with AlF4- simulated and activated G-protein-sensitive transmembrane sygnal, and signhificantly improved the oxidative injuries of the transmembrane macrowolecules and cardiovascular contraction proteins such as Na(+)-Ca2+ exchange protein induced by hypoxia.