HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 288/5/H2238    most recent 01095.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Gao, Z. Articles by Li, J. Search for Related Content PubMed PubMed Citation Articles by Gao, Z. Articles by Li, J.

Spinal P2X receptor modulates reflex pressor response to activation of muscle afferents

¹Division of Cardiology, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey; and ²Lebanon Veterans Affairs Medical Center, Lebanon, Pennsylvania

Submitted 27 October 2004 ; accepted in final form 21 December 2004

Static contraction of skeletal muscle evokes increases in blood pressure and heart rate. Previous studies suggested that the dorsal horn of the spinal cord is the first synaptic site responsible for those cardiovascular responses. In this study, we examined the role of ATP-sensitive P2X receptors in the cardiovascular responses to contraction by microdialyzing the P2X receptor antagonist pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) into the L7 level of the dorsal horn of nine anesthetized cats. Contraction was elicited by electrical stimulation of the L7 and S1 ventral roots. Blockade of P2X receptor attenuated the contraction induced-pressor response [change in mean arterial pressure (MAP): 16 ± 4 mmHg after 10 mM PPADS vs. 42 ± 8 mmHg in control; P < 0.05]. In addition, the pressor response to muscle stretch was also blunted by PPADS (MAP: 27 ± 5 mmHg after PPADS vs. 49 ± 8 mmHg in control; P < 0.05). Finally, activation of P2X receptor by microdialyzing 0.5 mM ,-methylene into the dorsal horn significantly augmented the pressor response to contraction. This effect was antagonized by prior PPADS dialysis. These data demonstrate that blockade of P2X receptors in the dorsal horn attenuates the pressor response to activation of muscle afferents and that stimulation of P2X receptors enhances the reflex response, indicating that P2X receptors play a role in mediating the muscle pressor reflex at the first synaptic site of this reflex.

adenosine 5'-triphosphate; dorsal horn; muscle contraction; blood pressure

This article has been cited by other articles:

				J. Li, J. Lu, Z. Gao, S. Koba, J. Xing, N. King, and L. Sinoway Spinal P2X receptor modulates muscle pressor reflex via glutamate J Appl Physiol, March 1, 2009; 106(3): 865 - 870. [Abstract] [Full Text] [PDF]

				A. E. Kindig, S. G. Hayes, and M. P. Kaufman Blockade of purinergic 2 receptors attenuates the mechanoreceptor component of the exercise pressor reflex Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2995 - H3000. [Abstract] [Full Text] [PDF]

				G. Burnstock Physiology and Pathophysiology of Purinergic Neurotransmission Physiol Rev, April 1, 2007; 87(2): 659 - 797. [Abstract] [Full Text] [PDF]

				P. M. Schmitt, K. Gohil, and M. P. Kaufman Spinal estrogen attenuates the exercise pressor reflex but has little effect on the expression of genes regulating neurotransmitters in the dorsal root ganglia J Appl Physiol, March 1, 2006; 100(3): 958 - 964. [Abstract] [Full Text] [PDF]