Transmembrane Action Potentials from Smooth Muscle in Turtle Arteries and Veins

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Science  15 Sep 1961:
Vol. 134, Issue 3481, pp. 736-737
DOI: 10.1126/science.134.3481.736


Transmembrane potential and active tension were measured in isolated segments of turtle aorta and inferior vena cava. Changes in tension were associated with action potentials, but the potentials had a different pattern in the two tissues. When the frequency of the action potentials increased, the contractions summated, resulting in a steadily maintained contraction.