Abstract
The permeation of monovalent organic cations through adenosine 3′,5′-cyclic monophosphate-(cAMP) activated channels was studied by recording macroscopic currents in excised inside-out membrane patches from the dendritic knobs of isolated mammalian olfactory receptor neurons (ORNs). Current-voltage relations were measured when bathing solution Na+ was replaced by monovalent organic cations. Permeability ratios relative to Na+ ions were calculated from changes in reversal potentials. Some of the small organic cations tested included ammonium (NH +4 ), hydroxylammonium and formamidinium, with relative permeability ratios of 1.41, 2.3 and 1.01 respectively. The larger methylated and ethylated ammonium ions studied included: DMA (dimethylammonium), TMA (tetramethylammonium) and TEA (tetraethylammonium) and they all had permeability ratios larger than 0.09. Even large cations such as choline, arginine and tris(hydroxymethyl)aminomethane (Tris) were appreciably permeant through the cAMP-activated channel with permeability ratios ranging from 0.19 to 0.7. The size of the permeating cations, as assessed by molecular weight, was a good predictor of the permeability. The permeability sequence of the cAMP-activated channel in our study was PNH4 > PNa > pDMA > pTMA > PCholine > PTEA. Higher permeability ratios of hydroxylammonium, arginine and tris(hydroxymethyl)aminomethane cannot be explained by ionic size alone. Our results indicate that: (i) cAMP-activated channels poorly select between monovalent cations; (ii) the pore dimension must be at least 6.5 × 6.5 Å, in order to allow TEA and Tris to permeate and (iii) molecular sieving must be an important mechanism for the permeation of large organic ions through the channels with specific ion binding playing a smaller role than in other structurally similar channels. In addition, the results clearly indicate that cyclic nucleotide-gated (CNG) channels in different cells are not the same, the olfactory CNG channel being different from that of the photoreceptors, particularly with respect to the permeation of large organic cations, which the ORN channels allow to permeate readily.
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References
Adams, D.J., Dwyer, T.M., Hille, B. 1980. The permeability of end-plate channels to monovalent and divalent metal cations. J. Gen. Physiol. 75:493–510
Balasubramanian, S., Lynch, J.W., Barry, P.H. 1994. Permeation of organic cations through cAMP-gated channels in mammalian olfactory receptor neurons. Proc. Aust. Physiol. Pharmacol. Soc. 25:125P
Barry, P.H. 1994. JPCalc, a software package for calculating liquid junction potential corrections in patch-clamp, intracellular, epithelial and bilayer measurements and for correcting junction potential measurements. J. Neurosci. Methods 51:107–116
Barry, P.H., Gage, P.W. 1984. Ionic selectivity of channels at the end plate. Curr. Top. Membr. Transp. 21:1–51
Bers, D.M. 1982. A simple method for the accurate determination of free [Ca2+] in Ca-EGTA solutions. Am. J. Physiol. 242:C404–408
Biel, M., Altenhofen, W., Hullin, R., Ludwig, I., Freichel, M., Flockerzi, V., Dascal, N., Kaupp, U.B., Hofmann, F. 1993. Primary structure and functional expression of a cyclic nucleotide-gated channel from rabbit aorta. FEBS Lett. 320:134–138
Boekhoff, I., Tareilus, E., Strotmann, J., Breer, H. 1990. Rapid activation of alternate second messenger pathways in olfactory cilia from rats by different odorants. EMBO J. 9:2453–2458
Dryer, S.E., Henderson, D. 1991. A cyclic GMP-activated channel in dissociated cells of the chick pineal gland. Nature 353:756–758
Dwyer, T.M., Adams, D.J., Hille, B. 1980. The permeability of the endplate channel to organic cations in frog muscle. J. Gen. Physiol. 75:469–492
Eisenman, G., Horn, R. 1983. Ionic selectivity revisited: the role of kinetic and equilibrium processes in ionic permeation through channels. J. Membrane Biol. 76:197–225
Eisenman, G., Krasne, S., Ciani, S. 1976. Further studies on ion selectivity. In: Ion Selective Electrodes and Enzyme Electrodes in Medicine and Biology, M. Kessler, L. Clark, D. Lubbers, I. Silver, W. Simon, editors, pp. 3–22. Urban and Schwarzenberg, Munich
Fatima-Shad, K., Barry, P.H. 1993. Anion permeabilities in GABA-and glycine-gated channels of mammalian cultured hippocampal neurons. Proc. R. Soc. Lond. B 253:69–75
Fesenko, E.E., Kolesnikov, S.S., Lyubarsky, A.L. 1985. Induction by cGMP of cationic conductance in plasma membrane of retinal rod outer segment. Nature 313:310–313
Firestein, S., Shepherd, G.M., Werblin, F.S. 1990. Time course of the membrane current underlying sensory transduction in salamander olfactory receptor neurons. J. Physiol. 430:135–158
Frings, S., Lynch, J.W., Lindemann, B. 1992. Properties of cyclic nucleotide-gated channels mediating olfactory transduction: activation, selectivity, and blockage. J. Gen. Physiol. 100:45–67
Fukushima, Y., Hagiwara, S. 1985. Currents carried by monovalent cations through calcium channels in mouse neoplastic B lymphocytes. J. Physiol. 358:255–284
Goulding, E.H., Ngai, J., Kramer, R.H., Colicos, S., Axel, R., Siegalbaum, S.A., Chess, A. 1992. Molecular cloning and single-channel properties of the cyclic nucleotide-gated channel from catfish olfactory neurons. Neuron 8:45–58
Goulding, E.H., Tibbs, G.R., Liu, D., Siegalbaum, S.A. 1993. Role of H5 domain in determining the pore diameter and ion permeation through cyclic nucleotide-gated channels. Nature 364:61–64
Hamill, O.P., Marty, A., Neher, E., Sakmann, B., Sigworth, F.J. 1981. Improved patch-clamp techniques for high resolution current recording from cells and cell-free membrane patches. Pfluegers. Arch. Eur. J. Physiol. 391:85–100
Hatt, H., Ache, B.W. 1994. Cyclic nucleotide-and inositol phosphategated ion channels in lobster olfactory receptor neurons. Proc. Natl. Acad. Sci. USA 91:6264–6268
Haynes, L.W., Yau, K.W. 1985. Cyclic GMP-sensitive conductance in outer segment membrane of catfish cones. Nature 317:61–64
Hille, B. 1971. The permeability of the sodium channel to organic cations in myelinated nerve. J. Gen. Physiol. 58:599–619
Hille, B. 1972. The permeability of the sodium channel to metal cations in myelinated nerve. J. Gen. Physiol. 59:637–658
Hille, B. 1973. Potassium channels in myelinated nerve: Selective permeability to small cations. J. Gen. Physiol. 61:669–686
Hille, B. 1992. In: Ionic Channels of Excitable Membranes. Sinauer Associates, Sunderland, MA
Huang, L.M., Catterall, W.A., Ehrenstein, G. 1978. Selectivity of cations and nonelectrolytes for acetylcholine-activated channels in cultured muscle cells. J. Gen. Physiol. 71:397–410
Jan, L.Y., Jan, Y.N. 1990. A superfamily of ion channels. Nature 345:672
Kaupp, U.B. 1991. The cyclic nucleotide-gated channels of vertebrate photoreceptors and olfactory epithelium. Trends in Neurosciences 14:150–157
Kolesnikov, S.S., Rebrik, T.I., Zhainazarov, A.B., Tavartkiladze, G.A., Kalamkarov, G.R. 1991. A cyclic-AMP-gated conductance in cochlear hair cells. FEBS Lett. 290:167–170
Kramer, R.H., Siegalbaum, S.A. 1992. Intracellular Ca2+ regulates the sensitivity of cyclic nucleotide-gated channels in olfactory receptor neurons. Neuron 9:897–906
Kurahashi, T. 1990. The response induced by intracellular cyclic AMP in isolated olfactory receptor cells of the newt. J. Physiol. 430:355–371
Kurahashi, T., Shibuya, T. 1990. Ca2+-dependent adaptive properties in the solitary olfactory receptor cell of the newt. Brain Res. 515:61–268
Lynch, J.W., Barry, P.H. 1989. Action potentials initiated by single channels opening in a small neuron (rat olfactory receptor). Biophys. J. 55:755–768
Lynch, J.W., Barry, P.H. 1991. Properties of transient K+ currents and underlying single K+ channels in rat olfactory receptor neurons. J. Gen. Physiol. 97:1043–1072
Lynch, J.W., Lindemann, B. 1994. Cyclic nucleotide-gated channels of rat olfactory receptor cells: divalent cations control the sensitivity to cAMP. J. Gen. Physiol. 103:87–106
McCleskey, E.W., Almers, W. 1985. The Ca channel in skeletal muscle is a large pore. Proc. Natl. Acad. Sci. USA 82:7149–7153
Menini, A. 1990. Currents carried by monovalent cations through cyclic GMP-activated channels in excised patches from salamandar rods. J. Physiol. 424:167–185
Nakamura, T., Gold, G.H. 1987. A cyclic nucleotide-gated conductance in olfactory receptor cilia. Nature 325:442–444
Ng, B., Barry, P.H. 1995. The measurement of ionic mobilities of certain less common organic ions needed for junction potential corrections in electrophysiology. J. Neurosci. Methods 56:37–41
Pauling, L. 1960. Nature of the Chemical Bond. Cornell University Press, Ithaca, NY
Picco, C., Menini, A. 1993. The permeability of the cGMP-activated channel to organic cations in retinal rods of the tiger salamander. J. Physiol. 460:741–758
Reed, R.R. 1992. Signaling pathways in odorant detection. Neuron 8:205–209
Ronnet, G.V., Cho, H., Hester, L.D., Wood, S.F., Snyder, S.H. 1993. Odorants differentially enhance phosphoinositide turnover and adenyl cyclase in olfactory receptor neuronal cultures. J. Neurosci. 13:1751–1758
Schild, D., Lischka, F.W. 1994. Amiloride-insensitive cation conductance in Xenopus laevis olfactory neurons: a combined patch clamp and calcium imaging analysis. Biophys. J. 66:299–304
Weyand, I., Godde, M., Frings, S., Weiner, J., Muller, F., Altenhofen, W., Hatt, H., Kaupp, U.B. 1994. Cloning and functional expression of a cyclic nucleotide-gated channel from mammalian sperm. Nature 368:859–863
Yoshii, K., Kurihara, K. 1983. Role of cations in olfactory reception. Brain Res. 274:239–248
Zimmerman, A.L., Karpen, J.W., Baylor, D.A. 1988. Hindered diffusion in excised membrane patches from retinal rod outer segments. Biophys. J. 54:351–355
Zufall, F., Firestein, S. 1993. Divalent cations block the cyclic nucleotide-gated channel of olfactory receptor neurons. J. Neurophysiol. 69:1758–1768
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This work was supported by the Australian Research Council of Australia.
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Balasubramanian, S., Lynch, J.W. & Barry, P.H. The permeation of organic cations through cAMP-gated channels in mammalian olfactory receptor neurons. J. Membarin Biol. 146, 177–191 (1995). https://doi.org/10.1007/BF00238007
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DOI: https://doi.org/10.1007/BF00238007