An increase in metabolic acidosis induced by chloralose anaesthesia in dogs after sino-vagal denervation.

Chloralose anaesthesia in dogs increased the H+ ion concentration significantly from its reference values. The findings favoured that it was most probably engendered through anaesthetic depression of neural centre regulating H+ ion concentration of blood. Such increase was largely contributed by a significant increase in its metabolic fraction. A further increase of metabolic fraction after separate and joint section of carotid sinus nerves and vagi indicated their holding effect. The section of carotid sinus nerve induced greater increase in this fraction than that of vagi. It indicated differences between the two nerves in their metabolic fraction controlling influence. Hyperpnoea after vagi section decreased the carbonic acid fraction, whereas marginally reduced ventilation after carotid sinus nerve section increased the carbonic acid fraction. Moreover, the overall changes in H+ ion concentration followed the changes in carbonic acid fraction. The present study suggested that the depressive effect of chloralose anaesthesia on H+ ion controlling neural mechanism could be largely determined by degree of increase in its metabolic fraction.