Abstract
1. Small and moderate doses of morphine sulphate cause an increase in the height of contraction of terrapin hearts perfused through their coronary systems.
2. Small doses of papaverine hydrochloride likewise increase the height of contraction of excised perfused terrapin hearts.
3. Moderate doses of papaverine hydrochloride cause a decrease in the height of the contraction of the perfused terrapin heart.
4. Large doses either of morphine sulphate or of papaverine hydrochloride cause temporary inhibition of cardiac activity. This is a more common effect of papaverine than of morphine.
5. The first few contractions following the cardiac arrest are higher than the average. This process simulates the recovery noted after arrest by vagus stimulation. Atropine sulphate does not abolish this phenomenon.
6. Papaverine hydrochloride increases the irritability of the terrapin heart until it finally causes fibrillation. A similar change can be induced by morphine though not so readily.
7. Fifty-two per cent of the fibrillating hearts rendered so by the injection of either papaverine or morphine were temporarily restored to normal rhythm by the injection of quinidine sulphate.
8. Terrapin hearts, fibrillating from excessive papaverine hydrochloride administration, were made to beat with regularity for a short time by the administration of large doses of morphine and vice versa.
9. The action of these opium alkaloids is the same upon excised hearts of rabbits and cats.
10. Both morphine and papaverine cause vasodilatation of the coronary blood vessels. (Confirmation of Macht.)
11. In the intact plethysmographed hearts of dogs and cats small doses of papaverine injected intravenously decrease cardiac volume. Large doses of papaverine cause dilatation of the heart.
Footnotes
- Received September 16, 1929.
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