Skip to main content

Some NLM-NCBI services and products are experiencing heavy traffic, which may affect performance and availability. We apologize for the inconvenience and appreciate your patience. For assistance, please contact our Help Desk at info@ncbi.nlm.nih.gov.

The Journal of Physiology logoLink to The Journal of Physiology
. 1996 Mar 15;491(Pt 3):663–668. doi: 10.1113/jphysiol.1996.sp021247

Ca2+ transients associated with openings of inositol trisphosphate-gated channels in Xenopus oocytes.

I Parker 1, Y Yao 1
PMCID: PMC1158808  PMID: 8815201

Abstract

1. The mechanisms underlying inositol 1,4,5-trisphosphate (InsP3)-induced Ca2+ liberation were studied in Xenopus oocytes by using scanning and stationary-point confocal fluorescence microscopy to record Ca2+ signals evoked by photorelease of InsP3 from a caged precursor. 2. Fluorescence measurements from confocal images showed that increasing [InsP3] evoked three distinct modes of Ca2+ liberation: a diffuse 'pacemaker' signal, localized transient puffs, and propagating waves. Peak free Ca2+ concentrations during waves and puffs (respectively, 2-5 microM and 100-200 nM) varied only slightly with [InsP3], whereas the pacemaker amplitude varied over a wider range (at least 1-30 nM Ca2+). 3. The improved resolution provided by confocal point recording revealed discontinuous Ca2+ 'blips' during pacemaker release. These events were resolved only at particular locations and had time courses similar to the puffs (rise, approximately 50 ms; decay, a few hundred milliseconds) but with amplitudes one-fifth or less of puff amplitudes. 4. We conclude that blips may arise through opening of single InsP3-gated channels, whereas puffs reflect the concerted opening of several clustered channels due to local regenerative feedback by Ca2+.

Full text

PDF
663

Selected References

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

  1. Berridge M. J. Inositol trisphosphate and calcium signalling. Nature. 1993 Jan 28;361(6410):315–325. doi: 10.1038/361315a0. [DOI] [PubMed] [Google Scholar]
  2. Bezprozvanny I., Watras J., Ehrlich B. E. Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum. Nature. 1991 Jun 27;351(6329):751–754. doi: 10.1038/351751a0. [DOI] [PubMed] [Google Scholar]
  3. Cannell M. B., Cheng H., Lederer W. J. Spatial non-uniformities in [Ca2+]i during excitation-contraction coupling in cardiac myocytes. Biophys J. 1994 Nov;67(5):1942–1956. doi: 10.1016/S0006-3495(94)80677-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Clays K., Hendrickx E., Triest M., Verbiest T., Persoons A., Dehu C., Brédas J. L. Nonlinear optical properties of proteins measured by hyper-rayleigh scattering in solution. Science. 1993 Nov 26;262(5138):1419–1422. doi: 10.1126/science.262.5138.1419. [DOI] [PubMed] [Google Scholar]
  5. Finch E. A., Turner T. J., Goldin S. M. Calcium as a coagonist of inositol 1,4,5-trisphosphate-induced calcium release. Science. 1991 Apr 19;252(5004):443–446. doi: 10.1126/science.2017683. [DOI] [PubMed] [Google Scholar]
  6. Iino M., Endo M. Calcium-dependent immediate feedback control of inositol 1,4,5-triphosphate-induced Ca2+ release. Nature. 1992 Nov 5;360(6399):76–78. doi: 10.1038/360076a0. [DOI] [PubMed] [Google Scholar]
  7. Ilyin V., Parker I. Role of cytosolic Ca2+ in inhibition of InsP3-evoked Ca2+ release in Xenopus oocytes. J Physiol. 1994 Jun 15;477(Pt 3):503–509. doi: 10.1113/jphysiol.1994.sp020211. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kasai H., Li Y. X., Miyashita Y. Subcellular distribution of Ca2+ release channels underlying Ca2+ waves and oscillations in exocrine pancreas. Cell. 1993 Aug 27;74(4):669–677. doi: 10.1016/0092-8674(93)90514-q. [DOI] [PubMed] [Google Scholar]
  9. Lechleiter J. D., Clapham D. E. Molecular mechanisms of intracellular calcium excitability in X. laevis oocytes. Cell. 1992 Apr 17;69(2):283–294. doi: 10.1016/0092-8674(92)90409-6. [DOI] [PubMed] [Google Scholar]
  10. López-López J. R., Shacklock P. S., Balke C. W., Wier W. G. Local, stochastic release of Ca2+ in voltage-clamped rat heart cells: visualization with confocal microscopy. J Physiol. 1994 Oct 1;480(Pt 1):21–29. doi: 10.1113/jphysiol.1994.sp020337. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Parker I., Ivorra I. Confocal microfluorimetry of Ca2+ signals evoked in Xenopus oocytes by photoreleased inositol trisphosphate. J Physiol. 1993 Feb;461:133–165. doi: 10.1113/jphysiol.1993.sp019506. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Parker I., Yao Y. Regenerative release of calcium from functionally discrete subcellular stores by inositol trisphosphate. Proc Biol Sci. 1991 Dec 23;246(1317):269–274. doi: 10.1098/rspb.1991.0154. [DOI] [PubMed] [Google Scholar]
  13. Stehno-Bittel L., Lückhoff A., Clapham D. E. Calcium release from the nucleus by InsP3 receptor channels. Neuron. 1995 Jan;14(1):163–167. doi: 10.1016/0896-6273(95)90250-3. [DOI] [PubMed] [Google Scholar]
  14. Yagodin S. V., Holtzclaw L., Sheppard C. A., Russell J. T. Nonlinear propagation of agonist-induced cytoplasmic calcium waves in single astrocytes. J Neurobiol. 1994 Mar;25(3):265–280. doi: 10.1002/neu.480250307. [DOI] [PubMed] [Google Scholar]
  15. Yao Y., Choi J., Parker I. Quantal puffs of intracellular Ca2+ evoked by inositol trisphosphate in Xenopus oocytes. J Physiol. 1995 Feb 1;482(Pt 3):533–553. doi: 10.1113/jphysiol.1995.sp020538. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Yao Y., Parker I. Potentiation of inositol trisphosphate-induced Ca2+ mobilization in Xenopus oocytes by cytosolic Ca2+. J Physiol. 1992 Dec;458:319–338. doi: 10.1113/jphysiol.1992.sp019420. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES