Adenosine-induced respiratory stimulation in man depends on site of infusion. Evidence for an action on the carotid body?

Adenosine is an endogenous nucleoside which stimulates respiration in man and other mammals. In animals adenosine appears to initiate respiratory stimulation within the carotid body, but whether this is the site of action in man is not known. We administered adenosine by intra-aortic infusion to 12 subjects undergoing cardiac catheterisation. When adenosine was infused at three sites proximal to the carotid circulation, minute ventilation was significantly higher than baseline values or those during adenosine infusion at a more distal site. These results support the hypothesis that adenosine-induced respiratory stimulation in man is mediated in the carotid body.