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TNP-ATP-resistant P2X ionic current on the central terminals and somata of rat primary sensory neurons.
J Neurophysiol 2003; 89(6):3235-42JN

Abstract

P2X receptors have been suggested to be expressed on the central terminals of A delta-afferent fibers innervating dorsal horn lamina V and play a role in modulating sensory synaptic transmission. These P2X receptors have been widely thought to be P2X2+3 receptors. However, we have recently found that P2X receptor-mediated modulation of sensory transmission in lamina V is not inhibited by trinitrophenyl-adenosine triphosphate (TNP-ATP), a potent antagonist of P2X1, P2X3 homomers, and P2X2+3 heteromers. To provide direct evidence for the presence of TNP-ATP-resistant P2X receptors on primary afferent fibers, we examined alpha,beta-methylene-ATP (alpha beta meATP)-evoked currents and their sensitivity to TNP-ATP in rat dorsal root ganglion (DRG) neurons. alpha beta meATP evoked fast currents, slow currents, and mixed currents that contained both fast and slow current-components. Fast currents and fast current components in the mixed currents were both completely inhibited by 0.1 microM TNP-ATP (n = 14). Both slow currents and slow-current components in the mixed currents showed broad spectrum of sensitivity to 1 microM TNP-ATP, ranging from complete block (TNP-ATP-sensitive) to little block (TNP-ATP-resistant). TNP-ATP-resistant currents evoked by 10 microM alpha beta meATP could be largely inhibited by 10 microM iso-pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid. Cells with P2X currents that were highly resistant to TNP-ATP were found to be insensitive to capsaicin. These results suggest that TNP-ATP-resistant P2X receptor subtypes are expressed on capsaicin-insensitive A delta-afferent fibers and play a role in modulating sensory transmission to lamina V neurons.

Authors+Show Affiliations

Department of Oral and Maxillofacial Surgery, McKnight Brain Institute and College of Dentistry, University of Florida, Gainesville, Florida 32610, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

12783957

Citation

Tsuzuki, Kenzo, et al. "TNP-ATP-resistant P2X Ionic Current On the Central Terminals and Somata of Rat Primary Sensory Neurons." Journal of Neurophysiology, vol. 89, no. 6, 2003, pp. 3235-42.
Tsuzuki K, Ase A, Séguéla P, et al. TNP-ATP-resistant P2X ionic current on the central terminals and somata of rat primary sensory neurons. J Neurophysiol. 2003;89(6):3235-42.
Tsuzuki, K., Ase, A., Séguéla, P., Nakatsuka, T., Wang, C. Y., She, J. X., & Gu, J. G. (2003). TNP-ATP-resistant P2X ionic current on the central terminals and somata of rat primary sensory neurons. Journal of Neurophysiology, 89(6), pp. 3235-42.
Tsuzuki K, et al. TNP-ATP-resistant P2X Ionic Current On the Central Terminals and Somata of Rat Primary Sensory Neurons. J Neurophysiol. 2003;89(6):3235-42. PubMed PMID: 12783957.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - TNP-ATP-resistant P2X ionic current on the central terminals and somata of rat primary sensory neurons. AU - Tsuzuki,Kenzo, AU - Ase,Ariel, AU - Séguéla,Philippe, AU - Nakatsuka,Terumasa, AU - Wang,Cong-Yi, AU - She,Jin-Xiong, AU - Gu,Jianguo G, PY - 2003/6/5/pubmed PY - 2003/8/2/medline PY - 2003/6/5/entrez SP - 3235 EP - 42 JF - Journal of neurophysiology JO - J. Neurophysiol. VL - 89 IS - 6 N2 - P2X receptors have been suggested to be expressed on the central terminals of A delta-afferent fibers innervating dorsal horn lamina V and play a role in modulating sensory synaptic transmission. These P2X receptors have been widely thought to be P2X2+3 receptors. However, we have recently found that P2X receptor-mediated modulation of sensory transmission in lamina V is not inhibited by trinitrophenyl-adenosine triphosphate (TNP-ATP), a potent antagonist of P2X1, P2X3 homomers, and P2X2+3 heteromers. To provide direct evidence for the presence of TNP-ATP-resistant P2X receptors on primary afferent fibers, we examined alpha,beta-methylene-ATP (alpha beta meATP)-evoked currents and their sensitivity to TNP-ATP in rat dorsal root ganglion (DRG) neurons. alpha beta meATP evoked fast currents, slow currents, and mixed currents that contained both fast and slow current-components. Fast currents and fast current components in the mixed currents were both completely inhibited by 0.1 microM TNP-ATP (n = 14). Both slow currents and slow-current components in the mixed currents showed broad spectrum of sensitivity to 1 microM TNP-ATP, ranging from complete block (TNP-ATP-sensitive) to little block (TNP-ATP-resistant). TNP-ATP-resistant currents evoked by 10 microM alpha beta meATP could be largely inhibited by 10 microM iso-pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid. Cells with P2X currents that were highly resistant to TNP-ATP were found to be insensitive to capsaicin. These results suggest that TNP-ATP-resistant P2X receptor subtypes are expressed on capsaicin-insensitive A delta-afferent fibers and play a role in modulating sensory transmission to lamina V neurons. SN - 0022-3077 UR - https://www.unboundmedicine.com/medline/citation/12783957/TNP_ATP_resistant_P2X_ionic_current_on_the_central_terminals_and_somata_of_rat_primary_sensory_neurons_ L2 - http://www.physiology.org/doi/full/10.1152/jn.01171.2002?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -