Abstract
1. Acid Ringer's solutions caused depression in the frog heart which increased with greater hydrogen-ion concentrations.
2. Alkaline Ringer's solutions produced moderate stimulation.
3. Small amounts of adrenalin in Ringer's solutions of a pH 7.2 to 7.9 caused marked stimulation.
4. Adrenalin in acid solution also produced stimulation, but this was not pronounced, was transitory and occurred only when the force and frequency were marked before perfusion with the drug. The stimulation was sometimes followed by depression.
5. Adrenalin in acid solution likewise caused depression, and sometimes also cardiac irregularity when heart action was moderate or weak, the depression being greater when the concentration of hydrogen ions was increased.
6. The depressive action of adrenalin in acid solution was attributed to stimulation of inhibitory fibers in the cardiac sympathetic.
Footnotes
- Received April 28, 1924.
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