[Effects of intracarotid injection of adenosine on respiration blood pressure and renal sympathetic nerve activity].

Changes of mean arterial pressure (MAP), heart rate (HR), respiration and renal sympathetic nerve activity (RSNA) induced by close-arterial administration of adenosine to carotid body (CB) were observed in 33 anesthetized rabbits. The results were as follows: (1) In response to intracarotid injections of adenosine, MAP decreased in a dose-dependent manner, while the frequency of respiration increases with little change in depth. Following carotid sinus denervation, intracarotid injection of adenosine still resulted in a decrease of MAP but with no changes in respiration. (2) By adding adenosine to perfusate of the isolated carotid sinus, both MAP and HR decreased, but these effects could be abolished by inactivation of carotid body. (3) MAP decreased and RSNA enhanced during perfusing adenosine into carotid sinus. These effects could be abolished by the section of sinus nerve or inactivation of CB. From the results obtained, it is considered that adenosine is capable of activating CB, decreasing MAP and heart rate but with a concomitant increases in respiration and RSNA.