Spinal P2X receptor modulates muscle pressor reflex via glutamate

Jianhua Li, Jian Lu, Zhaohui Gao, Satoshi Koba, Jihong Xing, Nicholas King, Lawrence Sinoway

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Static contraction of skeletal muscle evokes reflex increases in blood pressure and heart rate. Previous studies showed that P2X receptors located at the dorsal horn of the spinal cord play a role in modulating the muscle pressor reflex. P2X stimulation can alter release of the excitatory amino acid, glutamate (Glu). In this report, we tested the hypothesis that stimulation of P2X receptors enhances the concentrations of Glu ([Glu]) in the dorsal horn, and that blocking P2X receptors attenuates contraction-induced Glu increases and the resultant reflex pressor response. Contraction was elicited by electrical stimulation of the L7 and S1 ventral roots of 14 cats. Glu samples were collected from microdialysis probes inserted in the L7 level of the dorsal horn of the spinal cord, and dialysate [Glu] was determined using the HPLC method. First, microdialyzing α,β-methylene ATP (0.4 mM) into the dorsal horn significantly increased [Glu]. In addition, contraction elevated [Glu] from baseline of 536 ± 53 to 1,179 ± 192 nM (P < 0.05 vs. baseline), and mean arterial pressure by 39 ± 8 mmHg in the control experiment. Microdialyzing the P2X receptor antagonist pyridoxal phosphate-6-azophenyl-2′,4′-disulfonic acid (10 mM) into the dorsal horn attenuated the contraction induced-Glu increase (610 ± 128 to 759 ± 147 nM; P > 0.05) and pressor response (16 ± 3 mmHg, P < 0.05 vs. control). Our findings demonstrate that P2X modulates the cardiovascular responses to static muscle contraction by affecting the release of Glu in the dorsal horn of the spinal cord.

Original languageEnglish (US)
Pages (from-to)865-870
Number of pages6
JournalJournal of Applied Physiology
Volume106
Issue number3
DOIs
StatePublished - Mar 1 2009

Fingerprint

Reflex
Glutamic Acid
Muscles
Excitatory Amino Acids
Spinal Nerve Roots
Dialysis Solutions
Microdialysis
Muscle Contraction
Electric Stimulation
Skeletal Muscle
Cats
Adenosine Triphosphate
Heart Rate
High Pressure Liquid Chromatography
Spinal Cord Dorsal Horn
Blood Pressure

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Li, Jianhua ; Lu, Jian ; Gao, Zhaohui ; Koba, Satoshi ; Xing, Jihong ; King, Nicholas ; Sinoway, Lawrence. / Spinal P2X receptor modulates muscle pressor reflex via glutamate. In: Journal of Applied Physiology. 2009 ; Vol. 106, No. 3. pp. 865-870.
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Spinal P2X receptor modulates muscle pressor reflex via glutamate. / Li, Jianhua; Lu, Jian; Gao, Zhaohui; Koba, Satoshi; Xing, Jihong; King, Nicholas; Sinoway, Lawrence.

In: Journal of Applied Physiology, Vol. 106, No. 3, 01.03.2009, p. 865-870.

Research output: Contribution to journalArticle

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