*, Michael J. CATERINA, Tobias A. ROSEN, David JULIUS

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1 *, Michael J. CATERINA, Tobias A. ROSEN, David JULIUS Capsaicin, the main pungent ingredient in 'hot' chili peppers, elicits burning pain by activating specific vanilloid receptors on sensory nerve endings. We have isolated a functional cdna encoding a capsaicin receptor from sensory neurons using an expression cloning strategy. The cloned vanilloid receptor VR1 is a nonselective cation channel with six transmembrane domains that is structurally related to a member of the TRP family. VR1 is also activated by increases in temperature in the nonoxious range 43. We also find that protons decrease the temperature threshold for VR1 activation such that even moderately acidic conditions ph 5.9 activate VR1 at room temperature. Analysis of single-channel currents in excised membrane patches suggests that heat or proton gates VR1 directly. VR1 can therefore be viewed as a molecular integrator of chemical and physical stimuli that elicit pain. capsaicin / receptor / ion channel / heat / proton / pain C- fiber. nociceptor,, 1, 2. nociceptor,,. nociceptor,,,.,. resiniferatoxin capsazepine, 3, 4.,. 6,,, 5, 7.., nociceptor, Ca 2., Ca 2, 5. vanillyl, resiniferatoxin vanilloid 1a, vanilloid receptor subtype 1 VR1 The Capsaicin Receptor A Heat- and Proton-activated Ion Channel Makoto TOMINAGA*, Michael J. CATERINA, Tobias A. ROSEN, David JULIUS Department of Cellular and Molecular Pharmacology, University of California, San Francisco, U.S.A. *

2 a CH 3 CH CH CH O C NH CH 2 CH 3 CH 2 4 OCH 3 OH a b 2 na 40 s A A A C N 1 ab a vanillyl, resiniferatoxin vanilloid. b 6, 5, 6 H5., 3 ankyrin repeat domain A,. 5. VR1 Northern blot,., in situ hybridization, VR1., VR1 nociception. VR1, 6 1b. 6,, TRP family. VR1. 2, resiniferatoxin,, capsazepine, ruthenium red., VR1,, VR1 Ca 2. Ca 2 P Ca /P Na 9.6, Ca 2.,, bath solution, inside-out, outside-out, Na 77 ps ph 5.4 b c nm 44 ph 5.4 capasazepine 1 na 20 s a 1 µm 46a,, bph 5.4,, Ca 2 free, 60 mv. capsazepine 10 µm. Ca 2,. c 100 nm, 44, ph 5.4, excised patch, 40 mv. 2c. excised patch,.,,,.,,.,

3 ,.,,., VR1, Ca 2,., Ca 2,, Ca 2,, Ca 2 2a 5. PI., trp transient receptor potential,.,, Ca 2, trp Ca 2, Montelltrp 6., TRP Ca 2 store, Ca 2 store-operated Ca 2 channel. VR1 TRP family, Ca 2, VR1, TRP., VR1 store-operated Ca 2 channel,. VR1, Ca 2 thapsigargin Ca 2., storeoperated Ca 2 channel SKF 96365,., VR1 store-operated Ca 2 channel, 5. VR1,. TRP, Ca 2 store,,,,, VR1. burning pain., 1 a ph ph log M b ph ph pa/pf c ph 3 a. ph 7.4 EC nm. ph 6.4 EC50 60 nm. b. ph ph 6.4, 37. c. EC 50pH , VR1., 43, 49 3b. VR1., 43

4 ., VR1, Ca 2,,,, VR1.,, 2c., Ca 2,, 2a 7.,, 8, 9, VR1.,, Ca 2, VR1 heat sensor.,. heat sensor, Tsr,.,, 10., ph 6.,, 11., VR1 ph ,, submaximal 3a, b. ph 6.4,,, EC a. ph 6.4, 3b.,,. VR1. ph 6.4, 37,.,,, VR1, 22 VR1., ph 2b. ph 6.0, EC 50pH 5.4, 3c. H., Ca,,,,, 2b, c 7.,, 2. 1 Na 12, 13, 1, 11, 14. degenerin family 2 DRASIC dorsal root ganglia acid sensing ion channel 15,. DRASIC, DRASIC, VR1. VR1 3.,,.,.,,.,.,., VR1 2. VR1 TRP family VR1,, VR1,. aconitine veratridine, Na., 16., VR1.,.

5 , VR1 polymodal detector.,,. Ca 2 17., 18,,,,,,.,, VR1, vanilloid receptor-like protein 1 VRL VRL-1 VR1. VRL-1 vanilloid, resiniferatoxin, 50, 52, ruthenium red,, Ca 2, VR1. VR1 C fiber 7,, Aδ fiber 53 43, VRL-1, VRL-1 Aδ fiber 19.,. VRL-1 VRL-1, 50, VRL-1. VR1, VRL-1,., VR1, VRL-1,,.,,,,.,,. 1 Fields, H.L Pain, p.1-354, McGraw-Hill, New York. 2 Wall, P.D. and Melzack, R. eds1994 Textbook of pain., 3rd ed., p , Churchill Livingstone, Edinburgh. 3 Wood, J. ed1993 Capsaicin in the study of pain., p.1-286, Academic Press, London. 4 Holzer, P Capsaicin: Cellular targets, mechanisms of action, and selectivity for thin sensory neurons. Pharmacol. Rev. 43, Caterina, M.J., Schumacher, M.A., Tominaga, M. et al The capsaicin receptor: a heat-activated ion channel in the pain pathway.nature 389, Montell, C. and Rubin, G.M Molecular characterization of the Drosophila trp locus A putative integral membrane protein required for phototransduction. Neuron Tominaga, M., Caterina, M.J., Malmberg A.B. et al The cloned capsaicin receptor integrates multiple pain-producing stimuli. Neuron 21, Cesare, P.and McNaughton, P A novel heat-activated current in nociceptive neurons and its sensitization by bradykinin. Proc. Natl. Acad. Sci. 93, Reichling, D. B. and Levine, J. D Heat transduction in rat sensory neurons by calciumdependent activation of a cation channel. Proc. Natl. Acad. Sci. 94, ,, 1999 in press. 11 Bevan, S. and Geppetti, P Protons: Small stimulants of capsaicin-sensitive sensory nerves.trends neurosci. 17, Krishtal, O.A. and Pidoplichko, V. I A recptor for protons in the nerve cell membrane. Neuroscience 5, Konnerth, A. and Morad, M Protoninduced transformation of calcium channel in chick dorsal root ganglion cells. J. Physiol. 386, Bevan, S. and Yeats, J Protons activate a cation conductance in a subpopulation of rat dorsal root ganglion neurons. J. Physiol. 433, 145-

6 Waldmann, R., Champigny, G., Bassilana, F. et al A proton-gated channel involved in acid sensing. Nature 386, Strichartz, G., Rando, T. and Wang, G. K An integrated view of the molecular toxinology of sodium channel gating in excitable cells. Annu. Rev. Neurosci. 10, Kubo, Y., Miyashita, T. and Murata, Y Structure basis for a Ca 2 -sensing function of the metabotropic glutamate receptors. Science 279, Macnab, R. M in Escherichia Coli and Salmonella Typhimurium: Cellular and Molecular Biology. Neidhardt, F. C., Ingraham, J. L., Low, K. B., Magasanik, B., Schaechter, M., Umbarger, H. E. eds p American Society for Microbiology, Washington, D. C.. 19 Caterina M. J., Rosen T. A., Tominaga M. et al, 1999 Identification of a capsaicin receptor homologue with a high threshold for noxious heat. Nature 398 pp No.221,,,., , ,. Y. S.