THE DUAL NATURE OF THE ACTION OF SUCCINYLCHOLINE ON RESPIRATION IN CROSS-CIRCULATED DOGS

A total of 25 experiments in 6 pairs of cross-circulated dogs has shown that succinylcholine injected into the donor's femoral vein results in depression of ventilation in both donor and recipient; that succinyicholine injected into the recipient's femoral vein depresses ventilation in the recipient's body only; that succinyicholine injected into the carotid artery leading to the recipient's brain causes first an increase, then a decrease of ventilation in the recipient and decrease in ventilation in the donor. Additional experiments in 4 intact nembutalized dogs established dose-response curves and showed that similar depression of ventilation occurs when succinylcholine is injected either i.v. or via the intracarotid route. The validity of the experimental procedure and the mode of action of succinylcholine were briefly discussed.