Abstract
A strip of rabbit aorta was incubated in Krebs bicarbonate solution. Contraction of aortic strip induced by barium chloride was markedly potentiated by pretreatment with ouabain. The ouabain potentiation of contraction by barium was completely abolished either in calcium-deficient medium or by excess of potassium in medium. Extreme lowering of sodium concentration in medium also abolished the ouabain potentiation of Ba-induced contration. The potentiation of contraction was not affected by lack of glucose in medium. Aorta isolated from the reserpinized rabbit also showed the same response to barium and ouabain as aorta of the normal rabbit.
From the results obtained, it is evident that the ouabain potentiation of Ba-induced contraction of aorta is not related with catecholamine storage of blood vessel muscles but affected by change in calcium and potassium ions in medium.
