[Effect of tetraethylammonium on electrophysiologic properties of pulmonary artery smooth muscle cells].

Using the microelectrode technique combined with sucrose gap method it was shown that in the tetraethylammonium (TEA) solution a pulmonalis muscle cells exhibited spontaneous or elicited action potentials caused by depolarizing current. It is suggested that the appearance of the electrical activity due to inhibition with TEA of the voltage-dependent delayed potassium current, early activation of which in normal Krebs solution prevented the action potential development. Ca ions took part in the action potential generation because it was inhibited by Mn ions. Besides, delayed potassium current inhibition, TEA showed nonspecific action on the arterial muscle cells expressed in the following: 1) depolarizing action accompanied by increase of the membrane resistance; 2) stimulation of the extracellular calcium entry into the muscle cells followed by tonic muscle contraction; 3) establishment of coupling between the contraction and the resting potential.