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: 549/1/131    most recent 2002.031963v1 Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Labrakakis, C. Articles by MacDermott, A. B. Search for Related Content PubMed PubMed Citation Articles by Labrakakis, C. Articles by MacDermott, A. B.

Localization and function of ATP and GABA_A receptors expressed by nociceptors and other postnatal sensory neurons in rat

Charalampos Labrakakis, Chi-Kun Tong, Tamily Weissman, Carole Torsney and Amy B. MacDermott

The role of endogenous GABA and ATP in regulating transmitter release from primary afferent terminals in the superficial dorsal horn of the spinal cord is still controversial. ATP is co-released with GABA from some inhibitory dorsal horn neurons raising the possibility that ATP could act in concert with GABA to regulate transmitter release from primary afferent terminals if receptors to both transmitters are expressed there. Using electrophysiology together with immunocytochemistry, we have investigated the expression of ATP-gated P2X and GABA_A receptors by identified subpopulations of dorsal root ganglion (DRG) neurons known to project primarily to the superficial dorsal horn. Expression of the heat-sensitive vanilloid receptor 1 (VR1) and sensitivity to capsaicin were used to characterize DRG neurons sensitive to noxious heat. Both P2X and GABA_A receptors were expressed on the majority of DRG neurons examined. Recording compound action potentials (CAPs) from dorsal roots in the presence of muscimol, ,-methylene-ATP (,-meATP) or capsaicin resulted in depression of CAP in the slow and medium conducting fibres, indicating cognate receptor expression on the small diameter axons. Dorsal root-evoked dorsal root potentials (DR-DRPs), reflecting depolarization of primary afferent terminals by endogenously released substances, were depressed by the GABA_A receptor antagonist SR95531 and ,-meATP. These results suggest that GABA_A and P2X receptors are expressed on DRG cell bodies and slow fibre axons, many of which are heat-nociceptive. These fibres project to the superficial lamina of the dorsal horn where the receptors may function to modulate transmitter release near their central terminals.

This article has been cited by other articles:

				H. I. Rocha-Gonzalez, S. Mao, and F. J. Alvarez-Leefmans Na+,K+,2Cl- Cotransport and Intracellular Chloride Regulation in Rat Primary Sensory Neurons: Thermodynamic and Kinetic Aspects J Neurophysiol, July 1, 2008; 100(1): 169 - 184. [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]

				C.-K. Tong and A. B. MacDermott Both Ca2+-permeable and -impermeable AMPA receptors contribute to primary synaptic drive onto rat dorsal horn neurons J. Physiol., August 15, 2006; 575(1): 133 - 144. [Abstract] [Full Text] [PDF]

				E. Garcia-Nicas, J. M. A. Laird, and F. Cervero GABAA-Receptor Blockade Reverses the Injury-Induced Sensitization of Nociceptor-Specific (NS) Neurons in the Spinal Dorsal Horn of the Rat J Neurophysiol, August 1, 2006; 96(2): 661 - 670. [Abstract] [Full Text] [PDF]

				G.-Y. Xu and L.-Y. M. Huang Ca2+/calmodulin-dependent protein kinase II potentiates ATP responses by promoting trafficking of P2X receptors PNAS, August 10, 2004; 101(32): 11868 - 11873. [Abstract] [Full Text] [PDF]

				Y.-H. Jin, T. W. Bailey, B.-y. Li, J. H. Schild, and M. C. Andresen Purinergic and Vanilloid Receptor Activation Releases Glutamate from Separate Cranial Afferent Terminals in Nucleus Tractus Solitarius J. Neurosci., May 19, 2004; 24(20): 4709 - 4717. [Abstract] [Full Text] [PDF]

				R. Bardoni, C. Torsney, C.-K. Tong, M. Prandini, and A. B. MacDermott Presynaptic NMDA Receptors Modulate Glutamate Release from Primary Sensory Neurons in Rat Spinal Cord Dorsal Horn J. Neurosci., March 17, 2004; 24(11): 2774 - 2781. [Abstract] [Full Text] [PDF]