Electrophysiological-anatomic correlates of ATP-triggered vagal reflex in dogs. II. Vagal afferent traffic.

Extracellular ATP can act on chemosensitive vagal C-fiber nerve terminals in the lungs, thereby eliciting a pulmonary-cardiac depressor reflex. Previous studies have shown a right vagal dominance in afferent traffic elicited by intra-right atrial ATP. To elucidate the mechanism of this phenomenon, the following hypotheses were tested in a canine model. 1) Intra-right and intra-left pulmonary ATP elicit neural afferent traffic, which travels via the right and left vagus nerves, respectively. 2) Intra-right vs. intra-left pulmonary ATP causes similar suppression of sinus node automaticity. Data obtained in this study support both hypotheses and suggest that right vagal dominance in afferent neural traffic elicited by ATP is probably due to the action of ATP and/or its metabolites on nonpulmonary tissues.