Abstract

1. β-Erythroidine and substances derived from it (dihydro-β-erythroidine, α-tetrahydro-β-erythroidine, β-tetrahydro-β-erythroidine, sodium β-erythroidine, sodium dihydro-β-erythroidine, and β-erythroidine methiodide) possess typical curare-like action.

2. Compared with curare, the paralysis caused by these alkaloids, especially β-erythroidine, is of short duration.

3. Dihydro-β-erythroidine is the most potent of these alkaloids; it equals curarine in potency.

4. β-Erythroidine and dihydro-β-erythroidine are effective by oral administration. The toxicity has been determined in mice, rats, rabbits and cats following subcutaneous and oral administration.

5. Death in mammals is caused by paralysis of the diaphragm; the heart continues to beat in regular rhythm for several minutes.

6. Intravenous injections of β-erythroidine or dihydro-β-erythroidine cause a transient fall in blood pressure. In dogs they decreas emarkedly the heart rate and increase the atrio-ventricular conduction time.

7. Atropine prevents the bradycardia in non-anesthetized dogs, but fails to influence the bradycardia in animals anesthetized with sodium pentobarbital.

8. The smooth muscle is not affected by β-erythroidine.

9. Prostigmine is an effective antidote against β-erythroidine and dihydro-β-erythroidine. The antagonism between prostigmine and the two Erythrina alkaloids is mutual.

10. In contrast to the well known relation of tertiary and quaternary ammonium groups in curare alkaloids to their neuro-muscular action, conversion of β-erythroidine into the quaternary metho salt (β-erythroidine methiodide) decreases the curarizing action to about one-hundredth of the tertiary base.