[Functional effects of subthreshold stimulation of smooth muscle cells of the blood vessel].

The effect of subthreshold electrical stimulation of smooth muscle cells of the vessel wall upon the level of tonic tension developed by the smooth muscle in response to distention, was studied in isolated segments of the rat tail artery. Low concentrations of catecholamines--30-300 times lesser than those ordinarily observed in the blood--as well as subthreshold electrical stimuli were shown to affect functional properties of the blood vessel's smooth muscles, potentiating the tonic tension developed by the vessel in response to distention. Calcium ions are necessary for the development of potentiating effect of the subthreshold stimuli upon the tone of the blood vessels.