[Effect of physiologically-significant stimula on Ca2+/H+ exchange by myometrial cell membrane].

The effect of membrane potential, acetylcholine, carbachol and atropine on the myometrium plasmatic membrane Ca2+/H+ exchange was estimated. The change of artificially directed membrane potential from -40 to +20 mV was defined to provide for increasing the input of Ca2+ into vesicules and output of H+ from them in their concentration gradients. The similar changes of cations in membranes were registered under acetylcholine (10(-8)-10(-4) M) and carbachol (0.1 mM) action. Atropine displayed itself as decreasing the cholinomimetics effect to the tested ions transport. The exogenous 0.5 mM Ca2+ free of directed membrane potential as well stimulated the output of protons from vesicles. The supposition was made regarding H output strengthening and pH possible local increase of cytoplasm under the smooth cells activation by the membrane potential and acetylcholine.