The action of salicylates on the isolated heart

Abstract

Most of the experiments were carried out on the frog heart but turtles were also used occasionally. Sodium salicylate in different concentrations in Ringer's solution produced the following results:

A solution of 1:2000 caused no effect or stimulation. When the concentration was 1:1000 and the heart was exposed to the action of the salicylate for ten to fifteen minutes considerable depression occurred. Slight improvement was sometimes noticed when the sodium salicylate was discontinued, but complete recovery was never observed. Stronger solutions produced still greater depression; 1:500 caused cessation of heart action in two minutes, but some improvement also occurred in this case when perfusion with Ringer's solution was resumed. With a concentration of 1:250 depression was still more pronounced.

Marked depression of the heart also occurred when it was perfused with very weak solutions of acetylsalicylic acid (1 :4000 to 1 :2000). It was found, however, that this was due to the increased hydrogen ion concentration of the solution, for by adding sodium hydroxide or sodium bicarbonate until the P_H was 7.4 or 7.5 (the same as that of Ringer's solution) stimulation was produced when the heart was perfused with the acetyl derivative of the same molecular concentration as that of sodium salicylate. Stronger concentration (1 :250), however, caused cardiac depression though the hydrogen ion concentration was corrected as above to correspond with that of the Ringer's solution. The results show, therefore, that sodium salicylate is more toxic than the corresponding acetyl derivative. Similar results were obtained by Dreser 1 who perfused the frog heart with sodium salicylate and aspirin in defibrinated ox blood.

Experiments were also performed with methyl and ethyl salicylates. A saturated solution of the former (0.07 per cent. or less) produced complete heart block within two or three minutes which was promptly removed by perfusion with Ringer's solution alone.