[The comparative characteristics of the transmembrane ionic currents and the caffeine-induced responses of the smooth-muscle cells in the normal jejunum and under ionizing radiation exposure].

: A comparative investigation of transmembrane ion currents and caffeine-induced responses of single smooth muscle cells isolated from the circular layer of rat small intestine was carried out by the method of "patch-clamp". No reliable difference in potential-dependent and amplitude-kinetic characteristics of transmembrane ion currents in cells of intact and irradiated with dose of 3 Gy rats was revealed. In cells of irradiated animals external application of caffeine (4 mM) was not accompanied by strong quick-inactivated transient Ca(2+)-dependent potassium current as in control. The results obtained suggest that single whole-body X-ray irradiation with dose of 3 Gy does not lead in 5 days to any reliable alteration of potential-controlled channels of rat small intestine smooth muscle cell plasma membranes causing at the same time the disturbance of Ca-binding function of intracellular pools.