Advertisement

Journal of Biomedical Science

, Volume 7, Issue 4, pp 304–310 | Cite as

Effects of capacitative calcium entry on agonist-induced calcium transients in A7r5 vascular smooth muscle cells

  • Jason D. Gardner
  • Joseph N. Benoit
Original Paper

Abstract

Objective: The purpose of this study was to evaluate the contribution of capacitative calcium influx to intracellular calcium levels during agonist-induced stimulation of vascular smooth muscle cells.Methods: Aortic vascular smooth muscle cells (A7r5) were loaded with Indo-1 and intracellular calcium transients were measured. Cells were challenged with either arginine vasopressin (0.5 µM) or thapsigargin (1 µM). Lanthanum (1 mM) was used to block capacitative calcium influx through store-operated channels. Calcium traces were analyzed for basal, peak and plateau responses. Recordings were derivatized and integrated to gain additional information. Nonlinear regression provided a time constant that describes restoration of ionic equilibrium involving both sequestration and extrusion pathways.Results: Stimulation of cells with thapsigargin produced a non-L-type calcium influx that was attenuated by lanthanum. Cells excited with vasopressin exhibited a rapid calcium increase followed by a gradual decrease to a plateau level. Lanthanum pretreatment prior to stimulation caused no significant change in baseline, peak or plateau calcium levels as compared to control. Lanthanum caused no significant change in maximal calcium release rate, calcium integrals or time constant as compared to control.Conclusions: Capacitative calcium entry can occur in vascular smooth muscle cells, but does not appear to contribute significantly to the vasopressin response.

Key Words

Calcium Cell Channels, store-operated Calcium influx, capacitative Vasopressin Smooth muscle, vascular Thapsigargin Lanthanum Nifedipine A7r5 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Berridge MJ. Capacitative calcium entry. Biochem J 312:1–11;1995.Google Scholar
  2. 2.
    Bolton TB. Mechanisms of action of transmitters and other substances on smooth muscle. Physiol Rev 59:606–718;1979.Google Scholar
  3. 3.
    Broad LM, Cannon TR, Taylor CW. A non-capacitative pathway activated by arachidonic acid is the major Ca2+ entry mechanism in rat A7r5 smooth muscle cells stimulated with low concentrations of vasopressin. J Physiol 517:121–134;1999.Google Scholar
  4. 4.
    Casteels R, Droogmans G. Exchange characteristics of the noradrenaline-sensitive calcium store in vascular smooth muscle cells of rabbit ear artery. J Physiol 317:263–279;1981.Google Scholar
  5. 5.
    Darby P, Kwan C, Daniel EE. Use of calcium pump inhibitors in the study of calcium regulation in smooth muscle. Biol Signals 2:293–304;1993.Google Scholar
  6. 6.
    Devine CE, Somlyo AV, Somlyo AP. Sarcoplasmic reticulum and excitation-contraction coupling in mammalian smooth muscle. J Cell Biol 52:690–718;1972.Google Scholar
  7. 7.
    Edman KAP, Schild HO. The need for Ca2+ in the contractile responses induced by acetylcholine and K+ in the rat uterus. J Physiol 161:424–441;1962.Google Scholar
  8. 8.
    Fasolato C, Hoth M, Penner R. A GTP-dependent step in the activation mechanism of capacitative calcium entry. J Biol Chem 268:20737–20740;1993.Google Scholar
  9. 9.
    Gibson A, McFadzean I, Wallace P, Wayman CP. Capacitative Ca2+ entry and the regulation of smooth muscle tone. Trends Pharmacol Sci 197:266–269;1998.Google Scholar
  10. 10.
    Hofer A, Fasolato C, Pozzan T. Capacitative Ca2+ entry is closely linked to the filling state of internal Ca2+ stores: A study using simultaneous measurements of ICRAC and intraluminal [Ca2+]. J Cell Biol 140(2):325–334;1998.Google Scholar
  11. 11.
    Huang Y, Putney JW Jr. Relationship between intracellular calcium store depletion and calcium release-activated calcium current in a mast cell line (RBL-1). J Biol Chem 273:19554–19559;1998.Google Scholar
  12. 12.
    Irvine RF. ‘Quantal’ Ca2+ release and the control of Ca2+ entry by insoitol phosphates — a possible mechanism. FEBS Lett 263:5–9;1990.Google Scholar
  13. 13.
    Kaplan N, Di Salvo J. Coupling between [arginine8]-vasopressin-activated increases in protein tyrosine phosphorylation and cellular calcium in A7r5 aortic smooth muscle cells. Arch Biochem Biophys 326(2):271–280;1996.Google Scholar
  14. 14.
    Low AM, Lang RJ, Daniel EE. Influence of internal calcium stores on calcium-activated membrane currents in smooth muscle. Biol Signals 2:263–271;1993.Google Scholar
  15. 15.
    McDonald TV, Premack BA, Gardner P. Flash photolysis of caged inositol 1,4,5-triphosphate activates plasma membrane calcium current in human T cells. J Biol Chem 268:3889–3896;1993.Google Scholar
  16. 16.
    Nakajima T, Hazama H, Hamada E, Wu S, Iharashi K, Yamashita T, Seyama Y, Omata M, Kurachi Y. Endothelin-1 and vasopressin activate Ca2+-permeable non-selective cation channels in aortic smooth muscle cells: Mechanism of receptor-mediated Ca2+ influx. J Mol Cell Cardiol 28:707–722;1996.Google Scholar
  17. 17.
    Parekh A, Penner R. Store depletion and calcium influx. Physiol Rev 77:901–930;1997.Google Scholar
  18. 18.
    Patterson RL, van Rossum DB, Gill DL. Store-operated Ca2+ entry: Evidence for a secretion-like coupling model. Cell 98:487–499;1999.Google Scholar
  19. 19.
    Putney JW Jr. Capacitative calcium entry revisited. Cell Calcium 11:611–624;1990.Google Scholar
  20. 20.
    Putney JW Jr, McKay RR. Capacitative calcium entry channels. Bioessays 21:38–46;1999.Google Scholar
  21. 21.
    Rzigalinski BA, Willoughby KA, Hoffman SW, Falck JR, Ellis EF. Calcium influx factor, further evidence it is 5,6-epoxyeicosatrienoic acid. J Biol Chem 274(1):175–182;1999.Google Scholar
  22. 22.
    Skutella M, Ruegg U. Studies on capacitative calcium entry in vascular smooth muscle cells by measuring45Ca2+ influx. J Recept Signal Transduct Res 17(1–3):163–175;1997.Google Scholar
  23. 23.
    Somasundaram B, Norman JC, Mahaut-Smith MP. Primaquine, an inhibitor of vesicular transport, blocks the calcium release activated current in rat megakaryocytes. Biochem J 309:725–729;1995.Google Scholar
  24. 24.
    Thastrup O, Dawson AP, Scharff O, Foder B, Cullen PJ, Drobak BK, Bjerrum PJ, Christensen SB, Hanley MR. Thapsigargin, a novel molecular probe for studying intracellular calcium release and storage. Agents Actions 43:187–193;1994.Google Scholar
  25. 25.
    Treiman M, Caspersen C, Christensen S. A tool coming of age: Thapsigargin as an inhibitor of sarcoendoplasmic reticulum Ca2+-ATPases. Trends Pharmacol Sci 19(4):131–135;1998.Google Scholar
  26. 26.
    van Breemen C, Deth R. La+++ and excitation contraction coupling in vascular smooth muscle. In: Betz E, ed. Ionic Actions on Vascular Smooth Muscle. Berlin, Springer, 26–33;1976.Google Scholar
  27. 27.
    Xuan Y, Wang O, Whorton A. Thapsigargin stimulates Ca2+ entry in vascular smooth muscle cells: Nicardipine-sensitive and -insensitive pathways. Am J Physiol 262:C1258-C1265;1992.Google Scholar
  28. 28.
    Yao Y, Ferrer-Montiel AV, Montal M, Tsien RY. Activation of store-operated Ca2+ current in Xenopus oocytes requires SNAP-25 but not a diffusible messenger. Cell 98:475–485;1999.Google Scholar

Copyright information

© National Science Council 2000

Authors and Affiliations

  • Jason D. Gardner
    • 1
  • Joseph N. Benoit
    • 1
  1. 1.Department of Physiology, MSB 3024University of South AlabamaMobileUSA

Personalised recommendations