Abstract
The recent demonstration of proton signaling in C. elegans muscle contraction suggests a novel mechanism for proton-based intercellular communication and has stimulated enthusiasm for exploring proton signaling in higher organisms. Emerging evidence indicates that protons are produced and regulated in localized space and time. Furthermore, identification of proton regulators and sensors in the brain leads to the speculation that proton production and regulation may be of major importance for both physiological and pathological functions ranging from nociception to learning and memory. Extracellular protons may play a role in signal transmission by not only acting on adjacent cells but also affecting the cell from which they were released. In this review, we summarize the upstream and downstream pathways of proton production and regulation in the mammalian brain, with special emphasis on the proton extruders and sensors that are critical in the homeostatic regulation of pH, and discuss their potential roles in proton signaling under normal and pathophysiological conditions.
Keywords: proton extruders, proton sensors, pH homeostasis, proton signaling, pH microdomains, local accumulation
References
- [1].Casey J.R., Grinstein S., Orlowski J. Sensors and regulators of intracellular pH. Nat Rev Mol Cell Biol. 2010;11:50–61. doi: 10.1038/nrm2820. [DOI] [PubMed] [Google Scholar]
- [2].Bell S.M., Schreiner C.M., Schultheis P.J., Miller M.L., Evans R.L., Vorhees C.V., et al. Targeted disruption of the murine Nhe1 locus induces ataxia, growth retardation, and seizures. Am J Physiol. 1999;276:C788–795. doi: 10.1152/ajpcell.1999.276.4.C788. [DOI] [PubMed] [Google Scholar]
- [3].Suzuki A., Stern S.A., Bozdagi O., Huntley G.W., Walker R.H., Magistretti P.J., et al. Astrocyte-neuron lactate transport is required for long-term memory formation. Cell. 2011;144:810–823. doi: 10.1016/j.cell.2011.02.018. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [4].Wemmie J.A., Chen J., Askwith C.C., Hruska-Hageman A.M., Price M.P., Nolan B.C., et al. The acid-activated ion channel ASIC contributes to synaptic plasticity, learning, and memory. Neuron. 2002;34:463–477. doi: 10.1016/S0896-6273(02)00661-X. [DOI] [PubMed] [Google Scholar]
- [5].Pfeiffer J., Johnson D., Nehrke K. Oscillatory transepithelial H+ flux regulates a rhythmic behavior in C. elegans. Curr Biol. elegans. 2008;18:297–302. doi: 10.1016/j.cub.2008.01.054. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [6].Beg A.A., Ernstrom G.G., Nix P., Davis M.W., Jorgensen E.M. Protons act as a transmitter for muscle contraction in C.elegans. Cell. 2008;132:149–160. doi: 10.1016/j.cell.2007.10.058. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [7].Waldmann R., Champigny G., Bassilana F., Heurteaux C., Lazdunski M. A proton-gated cation channel involved in acid-sensing. Nature. 1997;386:173–177. doi: 10.1038/386173a0. [DOI] [PubMed] [Google Scholar]
- [8].DeVries S.H. Exocytosed protons feedback to suppress the Ca2+ current in mammalian cone photoreceptors. Neuron. 2001;32:1107–1117. doi: 10.1016/S0896-6273(01)00535-9. [DOI] [PubMed] [Google Scholar]
- [9].Palma A., Li L., Chen X.J., Pappone P., McNamee M. Effects of pH on acetylcholine receptor function. J Membr Biol. 1991;120:67–73. doi: 10.1007/BF01868592. [DOI] [PubMed] [Google Scholar]
- [10].Tang C.M., Dichter M., Morad M. Modulation of the N-methyl-D-aspartate channel by extracellular H+ Proc Natl Acad Sci U S A. 1990;87:6445–6449. doi: 10.1073/pnas.87.16.6445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [11].Traynelis S.F., Cull-Candy S.G. Proton inhibition of N-methyl-D-aspartate receptors in cerebellar neurons. Nature. 1990;345:347–350. doi: 10.1038/345347a0. [DOI] [PubMed] [Google Scholar]
- [12].Kaila K. Ionic basis of GABAA receptor channel function in the nervous system. Prog Neurobiol. 1994;42:489–537. doi: 10.1016/0301-0082(94)90049-3. [DOI] [PubMed] [Google Scholar]
- [13].Siesjo B.K., Katsura K., Mellergard P., Ekholm A., Lundgren J., Smith M.L. Acidosis-related brain damage. Prog Brain Res. 1993;96:23–48. [PubMed] [Google Scholar]
- [14].Kraut J.A., Madias N.E. Metabolic acidosis: pathophysiology, diagnosis and management. Nat Rev Nephrol. 2010;6:274–285. doi: 10.1038/nrneph.2010.33. [DOI] [PubMed] [Google Scholar]
- [15].Alberti K.G., Cuthbert C. The hydrogen ion in normal metabolism: a review. Ciba Found Symp. 1982;87:1–19. doi: 10.1002/9780470720691.ch1. [DOI] [PubMed] [Google Scholar]
- [16].Hochachka P.W., Mommsen T.P. Protons and anaerobiosis. Science. 1983;219:1391–1397. doi: 10.1126/science.6298937. [DOI] [PubMed] [Google Scholar]
- [17].Grinstein S., Furuya W., Biggar W.D. Cytoplasmic pH regulation in normal and abnormal neutrophils. Role of superoxide generation and Na+/H+ exchange. J Biol Chem. 1986;261:512–514. [PubMed] [Google Scholar]
- [18].Capasso M., DeCoursey T.E., Dyer M.J. pH regulation and beyond: unanticipated functions for the voltage-gated proton channel, HVCN1. Trends Cell Biol. 2011;21:20–28. doi: 10.1016/j.tcb.2010.09.006. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [19].Demaurex N., El Chemaly A. Physiological roles of voltage-gated proton channels in leukocytes. J Physiol. 2010;588:4659–4665. doi: 10.1113/jphysiol.2010.194225. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [20].Rehncrona S. Brain acidosis. Ann Emerg Med. 1985;14:770–776. doi: 10.1016/S0196-0644(85)80055-X. [DOI] [PubMed] [Google Scholar]
- [21].Dietrich C.J., Morad M. Synaptic acidification enhances GABAA signaling. J Neurosci. 2010;30:16044–16052. doi: 10.1523/JNEUROSCI.6364-09.2010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [22].Chesler M. Regulation and modulation of pH in the brain. Physiol Rev. 2003;83:1183–1221. doi: 10.1152/physrev.00010.2003. [DOI] [PubMed] [Google Scholar]
- [23].Swietach P., Zaniboni M., Stewart A.K., Rossini A., Spitzer K.W., Vaughan-Jones R.D. Modelling intracellular H+ ion diffusion. Prog Biophys Mol Biol. 2003;83:69–100. doi: 10.1016/S0079-6107(03)00027-0. [DOI] [PubMed] [Google Scholar]
- [24].Vaughan-Jones R.D., Peercy B.E., Keener J.P., Spitzer K.W. Intrinsic H+ ion mobility in the rabbit ventricular myocyte. J Physiol. 2002;541:139–158. doi: 10.1113/jphysiol.2001.013267. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [25].Spitzer K.W., Ershler P.R., Skolnick R.L., Vaughan-Jones R.D. Generation of intracellular pH gradients in single cardiac myocytes with a microperfusion system. Am J Physiol Heart Circ Physiol. 2000;278:H1371–1382. doi: 10.1152/ajpheart.2000.278.4.H1371. [DOI] [PubMed] [Google Scholar]
- [26].Stewart A.K., Boyd C.A., Vaughan-Jones R.D. A novel role for carbonic anhydrase: cytoplasmic pH gradient dissipation in mouse small intestinal enterocytes. J Physiol. 1999;516(Pt1):209–217. doi: 10.1111/j.1469-7793.1999.209aa.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [27].Forgac M. Vacuolar ATPases: rotary proton pumps in physiology and pathophysiology. Nat Rev Mol Cell Biol. 2007;8:917–929. doi: 10.1038/nrm2272. [DOI] [PubMed] [Google Scholar]
- [28].Lee J.H., Yu W.H., Kumar A., Lee S., Mohan P.S., Peterhoff C.M., et al. Lysosomal proteolysis and autophagy require presenilin 1 and are disrupted by Alzheimer-related PS1 mutations. Cell. 2010;141:1146–1158. doi: 10.1016/j.cell.2010.05.008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [29].Morel N., Dedieu J.C., Philippe J.M. Specific sorting of the a1 iso-form of the V-H+ATPase a subunit to nerve terminals where it associates with both synaptic vesicles and the presynaptic plasma membrane. J Cell Sci. 2003;116:4751–4762. doi: 10.1242/jcs.00791. [DOI] [PubMed] [Google Scholar]
- [30].Zhang Z., Nguyen K.T., Barrett E.F., David G. Vesicular ATPase inserted into the plasma membrane of motor terminals by exocytosis alkalinizes cytosolic pH and facilitates endocytosis. Neuron. 2010;68:1097–1108. doi: 10.1016/j.neuron.2010.11.035. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [31].Cardone R.A., Casavola V., Reshkin S.J. The role of disturbed pH dynamics and the Na+/H+ exchanger in metastasis. Nat Rev Cancer. 2005;5:786–795. doi: 10.1038/nrc1713. [DOI] [PubMed] [Google Scholar]
- [32].Denker S.P., Huang D.C., Orlowski J., Furthmayr H., Barber D.L. Direct binding of the Na—H exchanger NHE1 to ERM proteins regulates the cortical cytoskeleton and cell shape independently of H+ translocation. Mol Cell. 2000;6:1425–1436. doi: 10.1016/S1097-2765(00)00139-8. [DOI] [PubMed] [Google Scholar]
- [33].Denker S.P., Barber D.L. Cell migration requires both ion translocation and cytoskeletal anchoring by the Na-H exchanger NHE1. J Cell Biol. 2002;159:1087–1096. doi: 10.1083/jcb.200208050. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [34].Stock C., Schwab A. Role of the Na/H exchanger NHE1 in cell migration. Acta Physiol (Oxf) 2006;187:149–157. doi: 10.1111/j.1748-1716.2006.01543.x. [DOI] [PubMed] [Google Scholar]
- [35].Stuwe L., Muller M., Fabian A., Waning J., Mally S., Noel J., et al. pH dependence of melanoma cell migration: protons extruded by NHE1 dominate protons of the bulk solution. J Physiol. 2007;585:351–360. doi: 10.1113/jphysiol.2007.145185. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [36].Meima M.E., Mackley J.R., Barber D.L. Beyond ion translocation: structural functions of the sodium-hydrogen exchanger isoform-1. Curr Opin Nephrol Hypertens. 2007;16:365–372. doi: 10.1097/MNH.0b013e3281bd888d. [DOI] [PubMed] [Google Scholar]
- [37].Morris M.E., Felmlee M.A. Overview of the proton-coupled MCT (SLC16A) family of transporters: characterization, function and role in the transport of the drug of abuse gamma-hydroxybutyric acid. AAPS J. 2008;10:311–321. doi: 10.1208/s12248-008-9035-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [38].Pierre K., Pellerin L. Monocarboxylate transporters in the central nervous system: distribution, regulation and function. J Neurochem. 2005;94:1–14. doi: 10.1111/j.1471-4159.2005.03168.x. [DOI] [PubMed] [Google Scholar]
- [39].Halestrap A.P., Price N.T. The proton-linked monocarboxylate transporter (MCT) family: structure, function and regulation. Biochem J. 1999;343(Pt2):281–299. doi: 10.1042/0264-6021:3430281. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [40].Vandenberg J.I., Metcalfe J.C., Grace A.A. Mechanisms of pHi recovery after global ischemia in the perfused heart. Circ Res. 1993;72:993–1003. doi: 10.1161/01.res.72.5.993. [DOI] [PubMed] [Google Scholar]
- [41].Alberini C.M. Transcription factors in long-term memory and synaptic plasticity. Physiol Rev. 2009;89:121–145. doi: 10.1152/physrev.00017.2008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [42].Fields R.D., Stevens-Graham B. Neuroscience — New insights into neuron-glia communication. Science. 2002;298:556–562. doi: 10.1126/science.298.5593.556. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [43].Thomas R.C., Meech R.W. Hydrogen ion currents and intracellular pH in depolarized voltage-clamped snail neurones. Nature. 1982;299:826–828. doi: 10.1038/299826a0. [DOI] [PubMed] [Google Scholar]
- [44].Ramsey I.S., Moran M.M., Chong J.A., Clapham D.E. A voltage-gated proton-selective channel lacking the pore domain. Nature. 2006;440:1213–1216. doi: 10.1038/nature04700. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [45].Sasaki M., Takagi M., Okamura Y. A voltage sensor-domain protein is a voltage-gated proton channel. Science. 2006;312:589–592. doi: 10.1126/science.1122352. [DOI] [PubMed] [Google Scholar]
- [46].Decoursey T.E. Voltage-gated proton channels and other proton transfer pathways. Physiol Rev. 2003;83:475–579. doi: 10.1152/physrev.00028.2002. [DOI] [PubMed] [Google Scholar]
- [47].Eder C., DeCoursey T.E. Voltage-gated proton channels in microglia. Prog Neurobiol. 2001;64:277–305. doi: 10.1016/S0301-0082(00)00062-9. [DOI] [PubMed] [Google Scholar]
- [48].Lishko P.V., Botchkina I.L., Fedorenko A., Kirichok Y. Acid extrusion from human spermatozoa is mediated by flagellar voltage-gated proton channel. Cell. 2010;140:327–337. doi: 10.1016/j.cell.2009.12.053. [DOI] [PubMed] [Google Scholar]
- [49].Iovannisci D., Illek B., Fischer H. Function of the HVCN1 proton channel in airway epithelia and a naturally occurring mutation, M91T. J Gen Physiol. 2010;136:35–46. doi: 10.1085/jgp.200910379. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [50].Cheng Y.M., Kelly T., Church J. Potential contribution of a voltageactivated proton conductance to acid extrusion from rat hippocampal neurons. Neuroscience. 2008;151:1084–1098. doi: 10.1016/j.neuroscience.2007.12.007. [DOI] [PubMed] [Google Scholar]
- [51].DeCoursey T.E., Morgan D., Cherny V.V. The voltage dependence of NADPH oxidase reveals why phagocytes need proton channels. Nature. 2003;422:531–534. doi: 10.1038/nature01523. [DOI] [PubMed] [Google Scholar]
- [52].Henderson L.M., Chappell J.B., Jones O.T. The superoxide-generating NADPH oxidase of human neutrophils is electrogenic and associated with an H+ channel. Biochem J. 1987;246:325–329. doi: 10.1042/bj2460325. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [53].Pantazis A., Keegan P., Postma M., Schwiening C.J. The effect of neuronal morphology and membrane-permeant weak acid and base on the dissipation of depolarization-induced pH gradients in snail neurons. Pflugers Arch. 2006;452:175–187. doi: 10.1007/s00424-005-0019-4. [DOI] [PubMed] [Google Scholar]
- [54].Schwiening C.J., Willoughby D. Depolarization-induced pH microdomains and their relationship to calcium transients in isolated snail neurones. J Physiol. 2002;538(Pt2):371–382. doi: 10.1113/jphysiol.2001.013055. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [55].Lishko P.V., Kirichok Y. The role of Hv1 and CatSper channels in sperm activation. J Physiol. 2010;588:4667–4672. doi: 10.1113/jphysiol.2010.194142. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [56].Huang R.Q., Chen Z., Dillon G.H. Molecular basis for modulation of recombinant alpha1beta2gamma2 GABAA receptors by protons. J Neurophysiol. 2004;92:883–894. doi: 10.1152/jn.01040.2003. [DOI] [PubMed] [Google Scholar]
- [57].Wilkins M.E., Hosie A.M., Smart T.G. Identification of a beta subunit TM2 residue mediating proton modulation of GABA type A receptors. J Neurosci. 2002;22:5328–5333. doi: 10.1523/JNEUROSCI.22-13-05328.2002. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [58].Li Y.F., Wu L.J., Li Y., Xu L., Xu T.L. Mechanisms of H+ modulation of glycinergic response in rat sacral dorsal commissural neurons. J Physiol. 2003;552:73–87. doi: 10.1113/jphysiol.2003.047324. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [59].Chen Z., Dillon G.H., Huang R. Molecular determinants of proton modulation of glycine receptors. J Biol Chem. 2004;279:876–883. doi: 10.1074/jbc.M307684200. [DOI] [PubMed] [Google Scholar]
- [60].Traynelis S.F., Cull-Candy S.G. Pharmacological properties and H+ sensitivity of excitatory amino acid receptor channels in rat cerebellar granule neurones. J Physiol. 1991;433:727–763. doi: 10.1113/jphysiol.1991.sp018453. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [61].Krishtal O.A., Pidoplichko V.I. Receptor for protons in the membrane of sensory neurons. Brain Res. 1981;214:150–154. doi: 10.1016/0006-8993(81)90446-7. [DOI] [PubMed] [Google Scholar]
- [62].Wang Y.Y., Chang R.B., Liman E.R. TRPA1 is a component of the nociceptive response to CO2. J Neurosci. 2010;30:12958–12963. doi: 10.1523/JNEUROSCI.2715-10.2010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [63].Huang A.L., Chen X., Hoon M.A., Chandrashekar J., Guo W., Trankner D., et al. The cells and logic for mammalian sour taste detection. Nature. 2006;442:934–938. doi: 10.1038/nature05084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [64].Lingueglia E. Acid-sensing ion channels in sensory perception. J Biol Chem. 2007;282:17325–17329. doi: 10.1074/jbc.R700011200. [DOI] [PubMed] [Google Scholar]
- [65].Wemmie J.A., Price M.P., Welsh M.J. Acid-sensing ion channels: advances, questions and therapeutic opportunities. Trends Neurosci. 2006;29:578–586. doi: 10.1016/j.tins.2006.06.014. [DOI] [PubMed] [Google Scholar]
- [66].Xiong Z.G., Zhu X.M., Chu X.P., Minami M., Hey J., Wei W.L., et al. Neuroprotection in ischemia: blocking calcium-permeable acidsensing ion channels. Cell. 2004;118:687–698. doi: 10.1016/j.cell.2004.08.026. [DOI] [PubMed] [Google Scholar]
- [67].Sherwood T.W., Lee K.G., Gormley M.G., Askwith C.C. Heteromeric acid-sensing ion channels (ASICs) composed of ASIC2b and ASIC1a display novel channel properties and contribute to acidosisinduced neuronal death. J Neurosci. 2011;31:9723–9734. doi: 10.1523/JNEUROSCI.1665-11.2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [68].Gonzales E.B., Kawate T., Gouaux E. Pore architecture and ion sites in acid-sensing ion channels and P2X receptors. Nature. 2009;460:599–604. doi: 10.1038/nature08218. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [69].Jasti J., Furukawa H., Gonzales E.B., Gouaux E. Structure of acidsensing ion channel 1 at 1.9 A resolution and low pH. Nature. 2007;449:316–323. doi: 10.1038/nature06163. [DOI] [PubMed] [Google Scholar]
- [70].Zha X.M., Wemmie J.A., Green S.H., Welsh M.J. Acid-sensing ion channel 1a is a postsynaptic proton receptor that affects the density of dendritic spines. Proc Natl Acad Sci U S A. 2006;103:16556–16561. doi: 10.1073/pnas.0608018103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [71].Wemmie J.A., Askwith C.C., Lamani E., Cassell M.D., Freeman J.H., Jr., Welsh M.J. Acid-sensing ion channel 1 is localized in brain regions with high synaptic density and contributes to fear conditioning. J Neurosci. 2003;23:5496–5502. doi: 10.1523/JNEUROSCI.23-13-05496.2003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [72].Wemmie J.A., Coryell M.W., Askwith C.C., Lamani E., Leonard A.S., Sigmund C.D., et al. Overexpression of acid-sensing ion channel 1a in transgenic mice increases acquired fear-related behavior. Proc Natl Acad Sci U S A. 2004;101:3621–3626. doi: 10.1073/pnas.0308753101. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [73].Friese M.A., Craner M.J., Etzensperger R., Vergo S., Wemmie J.A., Welsh M.J., et al. Acid-sensing ion channel-1 contributes to axonal degeneration in autoimmune inflammation of the central nervous system. Nat Med. 2007;13:1483–1489. doi: 10.1038/nm1668. [DOI] [PubMed] [Google Scholar]
- [74].Gao J., Duan B., Wang D.G., Deng X.H., Zhang G.Y., Xu L., et al. Coupling between NMDA receptor and acid-sensing ion channel contributes to ischemic neuronal death. Neuron. 2005;48:635–646. doi: 10.1016/j.neuron.2005.10.011. [DOI] [PubMed] [Google Scholar]
- [75].Duan B., Wang Y.Z., Yang T., Chu X.P., Yu Y., Huang Y., et al. Extracellular spermine exacerbates ischemic neuronal injury through sensitization of ASIC1a channels to extracellular acidosis. J Neurosci. 2011;31:2101–2112. doi: 10.1523/JNEUROSCI.4351-10.2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [76].Duan B., Wu L.J., Yu Y.Q., Ding Y., Jing L., Xu L., et al. Upregulation of acid-sensing ion channel ASIC1a in spinal dorsal horn neurons contributes to inflammatory pain hypersensitivity. J Neurosci. 2007;27:11139–11148. doi: 10.1523/JNEUROSCI.3364-07.2007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [77].Ziemann A.E., Schnizler M.K., Albert G.W., Severson M.A., Howard M.A., 3rd, Welsh M.J., et al. Seizure termination by acidosis depends on ASIC1a. Nat Neurosci. 2008;11:816–822. doi: 10.1038/nn.2132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [78].Ziemann A.E., Allen J.E., Dahdaleh N.S., Drebot I.I., Coryell M.W., Wunsch A.M., et al. The amygdala is a chemosensor that detects carbon dioxide and acidosis to elicit fear behavior. Cell. 2009;139:1012–1021. doi: 10.1016/j.cell.2009.10.029. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [79].Yu Y., Chen Z., Li W.G., Cao H., Feng E.G., Yu F., et al. A nonproton ligand sensor in the acid-sensing ion channel. Neuron. 2010;68:61–72. doi: 10.1016/j.neuron.2010.09.001. [DOI] [PubMed] [Google Scholar]
- [80].Bohlen C.J., Chesler A.T., Sharif-Naeini R., Medzihradszky K.F., Zhou S., King D., et al. A heteromeric Texas coral snake toxin targets acidsensing ion channels to produce pain. Nature. 2011;479:410–414. doi: 10.1038/nature10607. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [81].Yarmolinsky D.A., Zuker C.S., Ryba N.J. Common sense about taste: from mammals to insects. Cell. 2009;139:234–244. doi: 10.1016/j.cell.2009.10.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [82].Chang R.B., Waters H., Liman E.R. A proton current drives action potentials in genetically identified sour taste cells. Proc Natl Acad Sci U S A. 2010;107:22320–22325. doi: 10.1073/pnas.1013664107. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [83].Luo M., Sun L., Hu J. Neural detection of gases — carbon dioxide, oxygen — in vertebrates and invertebrates. Curr Opin Neurobiol. 2009;19:354–361. doi: 10.1016/j.conb.2009.06.010. [DOI] [PubMed] [Google Scholar]
- [84].Kwon J.Y., Dahanukar A., Weiss L.A., Carlson J.R. The molecular basis of CO2 reception in Drosophila. Proc Natl Acad Sci U S A. 2007;104:3574–3578. doi: 10.1073/pnas.0700079104. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [85].Jones W.D., Cayirlioglu P., Kadow I.G., Vosshall L.B. Two chemosensory receptors together mediate carbon dioxide detection in Drosophila. Nature. 2007;445:86–90. doi: 10.1038/nature05466. [DOI] [PubMed] [Google Scholar]
- [86].Fischler W., Kong P., Marella S., Scott K. The detection of carbonation by the Drosophila gustatory system. Nature. 2007;448:1054–1057. doi: 10.1038/nature06101. [DOI] [PubMed] [Google Scholar]
- [87].Ai M., Min S., Grosjean Y., Leblanc C., Bell R., Benton R., et al. Acid sensing by the Drosophila olfactory system. Nature. 2010;468:691–695. doi: 10.1038/nature09537. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [88].Chandrashekar J., Yarmolinsky D., von Buchholtz L., Oka Y., Sly W., Ryba N.J., et al. The taste of carbonation. Science. 2009;326:443–445. doi: 10.1126/science.1174601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [89].Trapp S., Aller M.I., Wisden W., Gourine A.V. A role for TASK-1 (KCNK3) channels in the chemosensory control of breathing. J Neurosci. 2008;28:8844–8850. doi: 10.1523/JNEUROSCI.1810-08.2008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [90].Wang W.Z., Chu X.P., Li M.H., Seeds J., Simon R.P., Xiong Z.G. Modulation of acid-sensing ion channel currents, acid-induced increase of intracellular Ca2+, and acidosis-mediated neuronal injury by intracellular pH. J Biol Chem. 2006;281:29369–29378. doi: 10.1074/jbc.M605122200. [DOI] [PubMed] [Google Scholar]
- [91].Miesenbock G., De Angelis D.A., Rothman J.E. Visualizing secretion and synaptic transmission with pH-sensitive green fluorescent proteins. Nature. 1998;394:192–195. doi: 10.1038/28190. [DOI] [PubMed] [Google Scholar]
- [92].Liu Y., Edwards R.H. The role of vesicular transport proteins in synaptic transmission and neural degeneration. Annu Rev Neurosci. 1997;20:125–156. doi: 10.1146/annurev.neuro.20.1.125. [DOI] [PubMed] [Google Scholar]
- [93].Ertel E.A., Campbell K.P., Harpold M.M., Hofmann F., Mori Y., Perez-Reyes E., et al. Nomenclature of voltage-gated calcium channels. Neuron. 2000;25:533–535. doi: 10.1016/S0896-6273(00)81057-0. [DOI] [PubMed] [Google Scholar]
- [94].Birnbaumer L., Campbell K.P., Catterall W.A., Harpold M.M., Hofmann F., Horne W.A., et al. The naming of voltage-gated calcium channels. Neuron. 1994;13:505–506. doi: 10.1016/0896-6273(94)90021-3. [DOI] [PubMed] [Google Scholar]
- [95].Palmer M.J., Hull C., Vigh J., von Gersdorff H. Synaptic cleft acidification and modulation of short-term depression by exocytosed protons in retinal bipolar cells. J Neurosci. 2003;23:11332–11341. doi: 10.1523/JNEUROSCI.23-36-11332.2003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [96].Vessey J.P., Stratis A.K., Daniels B.A., Da Silva N., Jonz M.G., Lalonde M.R., et al. Proton-mediated feedback inhibition of presynaptic calcium channels at the cone photoreceptor synapse. J Neurosci. 2005;25:4108–4117. doi: 10.1523/JNEUROSCI.5253-04.2005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [97].Chen X.H., Bezprozvanny I., Tsien R.W. Molecular basis of proton block of L-type Ca2+ channels. J Gen Physiol. 1996;108:363–374. doi: 10.1085/jgp.108.5.363. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [98].Klockner U., Isenberg G. Calcium channel current of vascular smooth muscle cells: extracellular protons modulate gating and single channel conductance. J Gen Physiol. 1994;103:665–678. doi: 10.1085/jgp.103.4.665. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [99].Luscher B., Fuchs T., Kilpatrick C.L. GABAA receptor trafficking-mediated plasticity of inhibitory synapses. Neuron. 2011;70:385–409. doi: 10.1016/j.neuron.2011.03.024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [100].Cherubini E., Conti F. Generating diversity at GABAergic synapses. Trends Neurosci. 2001;24:155–162. doi: 10.1016/S0166-2236(00)01724-0. [DOI] [PubMed] [Google Scholar]
- [101].Jacob T.C., Moss S.J., Jurd R. GABAA receptor trafficking and its role in the dynamic modulation of neuronal inhibition. Nat Rev Neurosci. 2008;9:331–343. doi: 10.1038/nrn2370. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [102].Mozrzymas J.W., Zarnowska E.D., Pytel M., Mercik K. Modulation of GABAA receptors by hydrogen ions reveals synaptic GABA transient and a crucial role of the desensitization process. J Neurosci. 2003;23:7981–7992. doi: 10.1523/JNEUROSCI.23-22-07981.2003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [103].Krishek B.J., Smart T.G. Proton sensitivity of rat cerebellar granule cell GABAA receptors: dependence on neuronal development. J Physiol. 2001;530:219–233. doi: 10.1111/j.1469-7793.2001.0219l.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [104].Robello M., Balduzzi R., Cupello A. Modulation by extracellular pH of GABAA receptors expressed in Xenopus oocytes injected with rat brain mRNA. Int J Neurosci. 2000;103:41–51. doi: 10.3109/00207450009003251. [DOI] [PubMed] [Google Scholar]
- [105].Zhai J., Peoples R.W., Li C. Proton inhibition of GABA-activated current in rat primary sensory neurons. Pflugers Arch. 1998;435:539–545. doi: 10.1007/s004240050550. [DOI] [PubMed] [Google Scholar]
- [106].Pasternack M., Smirnov S., Kaila K. Proton modulation of functionally distinct GABAA receptors in acutely isolated pyramidal neurons of rat hippocampus. Neuropharmacology. 1996;35:1279–1288. doi: 10.1016/S0028-3908(96)00075-5. [DOI] [PubMed] [Google Scholar]
- [107].Kim J.S., Zhen M. Protons as intercellular messengers. Cell. 2008;132:21–22. doi: 10.1016/j.cell.2007.12.020. [DOI] [PubMed] [Google Scholar]