Effect of adenosine on chemosensory activity of the cat aortic body

Adenosine, which is released during hypoxia, increases carotid chemoreceptor discharge. It is not known if adenosine also may stimulate the aortic chemoreceptors. The purpose of this study was to investigate if adenosine also can stimulate aortic chemoreceptors. The effect of adenosine (0.01, 0.1 and 1.0 mumol/kg) on aortic chemoreceptor discharge was studied in seven anesthetized, paralyzed and artificially ventilated adult cats. Intra-aortic injections of adenosine produced an increase in chemoreceptor discharge, which reached its peak between 10 and 20 s. The chemoreceptor augmentation increased with higher doses of adenosine. Adenosine also caused a fall in blood pressure. The increase of chemoreceptor discharge was not related to fall in arterial blood pressure. Since adenosine is released during hypoxia, it is suggested that part of the cardiovascular changes induced by hypoxia is due to stimulation of aortic chemoreceptors by adenosine.