Submitted on August 31, 2007
Accepted on November 30, 2007
Role played by P2X and P2Y receptors in evoking the Muscle Chemoreflex
Shawn G. Hayes1*, Jennifer L. McCord1, and Marc P. Kaufman1
1 Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States
* To whom correspondence should be addressed. E-mail: shayes1{at}hmc.psu.edu.
The role played by purinergic 2Y receptors in evoking the muscle chemoreflex is not well defined. To shed light on this issue, we compared the pressor responses to popliteal arterial injection of UTP (1 mg/kg), a selective P2Y agonist, with those to popliteal arterial injection of ATP (1 mg/kg), a P2X and P2Y agonist, and to 
, 
-methylene ATP (50 µg/kg), a selective P2X1 and P2X3 agonist, in six decerebrate unanesthetized cats. We found that injection of ATP and , -methylene ATP increased mean arterial pressure by 19 ± 2 and 15 ± 4 mm Hg , whereas UTP had no effect on arterial pressure. In addition, the pressor responses to injection of ATP and , -methylene ATP were abolished by section of the sciatic nerve, demonstrating that they were reflex in origin. We conclude that P2Y receptors on thin fiber muscle afferents play no role in evoking the muscle chemoreflex.
