[The contractile activity of amphibian vein smooth muscle cells]

In frogs, the contractile activity of the antetior abdominal, femoral, and of the major skin veins was studied. The electric transmural stimulation, potassium chloride ions, and catecholamines were found to activate the contractile apparatus of the veins. Spontaneous mechanical activity was not characteristic of the vessels under study; acetylcholine and a rapid stretching of a vein's segment were followed by no active contractile response.