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. 1994 Feb;66(2 Pt 1):299–304. doi: 10.1016/s0006-3495(94)80804-5

Amiloride-insensitive cation conductance in Xenopus laevis olfactory neurons: a combined patch clamp and calcium imaging analysis.

D Schild 1, F W Lischka 1
PMCID: PMC1275695  PMID: 8161682

Abstract

We used digital calcium imaging with Fura-2 in conjunction with the tight-seal whole-cell patch clamp technique to describe a novel cation conductance in olfactory neurons of the clawed toad Xenopus laevis. Substitution of extracellular Ca2+ and Na+ was used as a tool to change [Ca2+]i. When [Ca2+]i was increased to about 450 nM, a conductance gcat activated that was permeable for cations. Upon gcat activation, an increase in [Ca2+]i occurred in the dendritic knob. Once activated, gcat showed no further dependence upon [Ca2+]i. Icat is shown to be different from the current activated by a mixture of the odorants citralva and amyl acetate. We conclude that there are two different cation conductances in the peripheral compartments of olfactory neurons in X. laevis.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bredt D. S., Snyder S. H. Nitric oxide mediates glutamate-linked enhancement of cGMP levels in the cerebellum. Proc Natl Acad Sci U S A. 1989 Nov;86(22):9030–9033. doi: 10.1073/pnas.86.22.9030. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Breer H., Klemm T., Boekhoff I. Nitric oxide mediated formation of cyclic GMP in the olfactory system. Neuroreport. 1992 Nov;3(11):1030–1032. doi: 10.1097/00001756-199211000-00022. [DOI] [PubMed] [Google Scholar]
  3. Fadool D. A., Ache B. W. Plasma membrane inositol 1,4,5-trisphosphate-activated channels mediate signal transduction in lobster olfactory receptor neurons. Neuron. 1992 Nov;9(5):907–918. doi: 10.1016/0896-6273(92)90243-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Firestein S., Darrow B., Shepherd G. M. Activation of the sensory current in salamander olfactory receptor neurons depends on a G protein-mediated cAMP second messenger system. Neuron. 1991 May;6(5):825–835. doi: 10.1016/0896-6273(91)90178-3. [DOI] [PubMed] [Google Scholar]
  5. Firestein S., Werblin F. Odor-induced membrane currents in vertebrate-olfactory receptor neurons. Science. 1989 Apr 7;244(4900):79–82. doi: 10.1126/science.2704991. [DOI] [PubMed] [Google Scholar]
  6. Frings S., Lynch J. W., Lindemann B. Properties of cyclic nucleotide-gated channels mediating olfactory transduction. Activation, selectivity, and blockage. J Gen Physiol. 1992 Jul;100(1):45–67. doi: 10.1085/jgp.100.1.45. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Frings S. Protein kinase C sensitizes olfactory adenylate cyclase. J Gen Physiol. 1993 Feb;101(2):183–205. doi: 10.1085/jgp.101.2.183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Grynkiewicz G., Poenie M., Tsien R. Y. A new generation of Ca2+ indicators with greatly improved fluorescence properties. J Biol Chem. 1985 Mar 25;260(6):3440–3450. [PubMed] [Google Scholar]
  9. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  10. Kleene S. J., Gesteland R. C. Calcium-activated chloride conductance in frog olfactory cilia. J Neurosci. 1991 Nov;11(11):3624–3629. doi: 10.1523/JNEUROSCI.11-11-03624.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kurahashi T. Activation by odorants of cation-selective conductance in the olfactory receptor cell isolated from the newt. J Physiol. 1989 Dec;419:177–192. doi: 10.1113/jphysiol.1989.sp017868. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Kurahashi T., Yau K. W. Co-existence of cationic and chloride components in odorant-induced current of vertebrate olfactory receptor cells. Nature. 1993 May 6;363(6424):71–74. doi: 10.1038/363071a0. [DOI] [PubMed] [Google Scholar]
  13. Lischka F. W., Schild D. Effects of nitric oxide upon olfactory receptor neurones in Xenopus laevis. Neuroreport. 1993 May;4(5):582–584. doi: 10.1097/00001756-199305000-00031. [DOI] [PubMed] [Google Scholar]
  14. Lischka F. W., Schild D. Standing calcium gradients in olfactory receptor neurons can be abolished by amiloride or ruthenium red. J Gen Physiol. 1993 Nov;102(5):817–831. doi: 10.1085/jgp.102.5.817. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Marks P. W., Maxfield F. R. Preparation of solutions with free calcium concentration in the nanomolar range using 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Anal Biochem. 1991 Feb 15;193(1):61–71. doi: 10.1016/0003-2697(91)90044-t. [DOI] [PubMed] [Google Scholar]
  16. Neher E., Augustine G. J. Calcium gradients and buffers in bovine chromaffin cells. J Physiol. 1992 May;450:273–301. doi: 10.1113/jphysiol.1992.sp019127. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Restrepo D., Miyamoto T., Bryant B. P., Teeter J. H. Odor stimuli trigger influx of calcium into olfactory neurons of the channel catfish. Science. 1990 Sep 7;249(4973):1166–1168. doi: 10.1126/science.2168580. [DOI] [PubMed] [Google Scholar]
  18. Restrepo D., Teeter J. H., Honda E., Boyle A. G., Marecek J. F., Prestwich G. D., Kalinoski D. L. Evidence for an InsP3-gated channel protein in isolated rat olfactory cilia. Am J Physiol. 1992 Sep;263(3 Pt 1):C667–C673. doi: 10.1152/ajpcell.1992.263.3.C667. [DOI] [PubMed] [Google Scholar]
  19. Restrepo D., Teeter J. H. Olfactory neurons exhibit heterogeneity in depolarization-induced calcium changes. Am J Physiol. 1990 Jun;258(6 Pt 1):C1051–C1061. doi: 10.1152/ajpcell.1990.258.6.C1051. [DOI] [PubMed] [Google Scholar]
  20. Ronnett G. V., Snyder S. H. Molecular messengers of olfaction. Trends Neurosci. 1992 Dec;15(12):508–513. doi: 10.1016/0166-2236(92)90104-g. [DOI] [PubMed] [Google Scholar]
  21. Schild D., Bischofberger J. Ca2+ modulates an unspecific cation conductance in olfactory cilia of Xenopus laevis. Exp Brain Res. 1991;84(1):187–194. doi: 10.1007/BF00231774. [DOI] [PubMed] [Google Scholar]
  22. Schild D. Whole-cell currents in olfactory receptor cells of Xenopus laevis. Exp Brain Res. 1989;78(2):223–232. doi: 10.1007/BF00228894. [DOI] [PubMed] [Google Scholar]

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