Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1990 Dec;431:243–267. doi: 10.1113/jphysiol.1990.sp018329

Membrane depolarization and intracellular Ca2+ increase caused by high external Ca2+ in a rat calcitonin-secreting cell line.

N Yamashita 1, S Hagiwara 1
PMCID: PMC1181773  PMID: 1712840

Abstract

1. Calcitonin secretion is regulated by the external Ca2+ concentration ([Ca2+]o) via a rise in intracellular Ca2+ concentration ([Ca2+]i). The mechanism which couples an increase in [Ca2+]o to an increase in [Ca2+]i was explored in a rat calcitonin-secreting cell line (rMTC 44-2). [Ca2+]i was monitored using Fura-2 AM, and the membrane potential or current was simultaneously measured. 2. Using the conventional whole-cell clamp, tetrodotoxin-sensitive voltage-gated Na+ channels, T- and L-type Ca2+ channels, and three types of K+ channels, the delayed K+ channel, the A-channel and the inward-rectifying channel were observed. 3. Using the nystatin-perforated whole-cell-clamp technique, the resting potential measured under current clamp in standard extracellular medium was -59.0 +/- 5.0 mV (mean +/- S.D., n = 25), and the input resistance was 3.9 +/- 1.9 G omega (n = 10). In 0.5 mM [Ca2+]o most cells (22/25) showed spontaneous action potentials. 4. An increase in [Ca2+]o depolarized the cell membrane and elevated [Ca2+]i even in the presence of 10 microM-tetrodotoxin. The rise in [Ca2+]i was greatly reduced when action potentials were inhibited by applying hyperpolarizing current. The increase in [Ca2+]i saturated with 3-4 mM [Ca2+]o. In 3 mM [Ca2+]o, [Ca2+]i was 188.9 +/- 40.5% (n = 12) of that in 0.5 mM [Ca2+]o. 5. In high [Ca2+]o the duration of action potentials was prolonged, but the action potential frequency did not always increase. In some cases it even decreased in high [Ca2+]o. 6. Two types of action potential were observed in high [Ca2+]o, one with a shorter duration and the other with a longer duration. [Ca2+]i transiently increased in association with the long-duration action potentials. These long-duration action potentials were also accompanied by a larger after-hyperpolarization. 7. Under voltage clamp, high [Ca2+]o caused a membrane conductance increase to Na+ ions. 8. Even when the membrane potential was clamped at a level below the threshold for Ca2+ channel activation, high [Ca2+]o provoked an increase of [Ca2+]i which was composed of an initial transient increase followed by a sustained increase, indicating an involvement of mechanisms other than Ca2+ influx through voltage-gated channels. The sustained increase was more frequently observed than the initial transient increase. The amplitude of the sustained phase was dependent on [Ca2+]o, and in 5 mM [Ca2+]o it was 120.9 +/- 18.9% (103-194%) (n = 58) of that in 0.5 mM [Ca2+]o.(ABSTRACT TRUNCATED AT 400 WORDS)

Full text

PDF
243

Selected References

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

  1. Almers W., McCleskey E. W., Palade P. T. A non-selective cation conductance in frog muscle membrane blocked by micromolar external calcium ions. J Physiol. 1984 Aug;353:565–583. doi: 10.1113/jphysiol.1984.sp015351. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Benham C. D. Voltage-gated and agonist-mediated rises in intracellular Ca2+ in rat clonal pituitary cells (GH3) held under voltage clamp. J Physiol. 1989 Aug;415:143–158. doi: 10.1113/jphysiol.1989.sp017716. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Biales B., Dichter M. A., Tischler A. Sodium and calcium action potential in pituitary cells. Nature. 1977 May 12;267(5607):172–174. doi: 10.1038/267172a0. [DOI] [PubMed] [Google Scholar]
  4. Bruce B. R., Anderson N. C., Jr Hyperpolarization in mouse parathyroid cells by low calcium. Am J Physiol. 1979 Jan;236(1):C15–C21. doi: 10.1152/ajpcell.1979.236.1.C15. [DOI] [PubMed] [Google Scholar]
  5. Colquhoun D., Neher E., Reuter H., Stevens C. F. Inward current channels activated by intracellular Ca in cultured cardiac cells. Nature. 1981 Dec 24;294(5843):752–754. doi: 10.1038/294752a0. [DOI] [PubMed] [Google Scholar]
  6. Cooper C. W., Borosky S. A., Farrell P. E., Steinsland O. S. Effects of the calcium channel activator BAY-K-8644 on in vitro secretion of calcitonin and parathyroid hormone. Endocrinology. 1986 Feb;118(2):545–549. doi: 10.1210/endo-118-2-545. [DOI] [PubMed] [Google Scholar]
  7. Fried R. M., Tashjian A. H., Jr Unusual sensitivity of cytosolic free Ca2+ to changes in extracellular Ca2+ in rat C-cells. J Biol Chem. 1986 Jun 15;261(17):7669–7674. [PubMed] [Google Scholar]
  8. Gagel R. F., Zeytinoğlu F. N., Voelkel E. F., Tashjian A. H., Jr Establishment of a calcitonin-producing rat medullary thyroid carcinoma cell line. II. Secretory studies of the tumor and cells in culture. Endocrinology. 1980 Aug;107(2):516–523. doi: 10.1210/endo-107-2-516. [DOI] [PubMed] [Google Scholar]
  9. Hagiwara S., Byerly L. Calcium channel. Annu Rev Neurosci. 1981;4:69–125. doi: 10.1146/annurev.ne.04.030181.000441. [DOI] [PubMed] [Google Scholar]
  10. Haller-Brem S., Muff R., Petermann J. B., Born W., Roos B. A., Fischer J. A. Role of cytosolic free calcium concentration in the secretion of calcitonin gene-related peptide and calcitonin from medullary thyroid carcinoma cells. Endocrinology. 1987 Oct;121(4):1272–1277. doi: 10.1210/endo-121-4-1272. [DOI] [PubMed] [Google Scholar]
  11. 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]
  12. Hess P., Tsien R. W. Mechanism of ion permeation through calcium channels. 1984 May 31-Jun 6Nature. 309(5967):453–456. doi: 10.1038/309453a0. [DOI] [PubMed] [Google Scholar]
  13. Hishikawa R., Fukase M., Takenaka M., Fujita T. Effect of calcium channel agonist Bay K 8644 on calcitonin secretion from a rat C-cell line. Biochem Biophys Res Commun. 1985 Jul 16;130(1):454–459. doi: 10.1016/0006-291x(85)90438-3. [DOI] [PubMed] [Google Scholar]
  14. Horn R., Marty A. Muscarinic activation of ionic currents measured by a new whole-cell recording method. J Gen Physiol. 1988 Aug;92(2):145–159. doi: 10.1085/jgp.92.2.145. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Jacob R., Murphy E., Lieberman M. Free calcium in isolated chick embryo heart cells measured using quin2 and fura-2. Am J Physiol. 1987 Aug;253(2 Pt 1):C337–C342. doi: 10.1152/ajpcell.1987.253.2.C337. [DOI] [PubMed] [Google Scholar]
  16. Kawa K. Voltage-gated sodium and potassium currents and their variation in calcitonin-secreting cells of the chick. J Physiol. 1988 May;399:93–113. doi: 10.1113/jphysiol.1988.sp017070. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kidokoro Y. Spontaneous calcium action potentials in a clonal pituitary cell line and their relationship to prolactin secretion. Nature. 1975 Dec 25;258(5537):741–742. doi: 10.1038/258741a0. [DOI] [PubMed] [Google Scholar]
  18. Kurtz A., Penner R. Angiotensin II induces oscillations of intracellular calcium and blocks anomalous inward rectifying potassium current in mouse renal juxtaglomerular cells. Proc Natl Acad Sci U S A. 1989 May;86(9):3423–3427. doi: 10.1073/pnas.86.9.3423. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Lewis D. L., Goodman M. B., St John P. A., Barker J. L. Calcium currents and fura-2 signals in fluorescence-activated cell sorted lactotrophs and somatotrophs of rat anterior pituitary. Endocrinology. 1988 Jul;123(1):611–621. doi: 10.1210/endo-123-1-611. [DOI] [PubMed] [Google Scholar]
  20. Lewis R. S., Cahalan M. D. Mitogen-induced oscillations of cytosolic Ca2+ and transmembrane Ca2+ current in human leukemic T cells. Cell Regul. 1989 Nov;1(1):99–112. doi: 10.1091/mbc.1.1.99. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. López-Barneo J., Armstrong C. M. Depolarizing response of rat parathyroid cells to divalent cations. J Gen Physiol. 1983 Aug;82(2):269–294. doi: 10.1085/jgp.82.2.269. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Morrissey J. J., Klahr S. Dissociation of membrane potential and hormone secretion in bovine parathyroid cells. Am J Physiol. 1983 Jul;245(1):E102–E105. doi: 10.1152/ajpendo.1983.245.1.E102. [DOI] [PubMed] [Google Scholar]
  23. Muff R., Nemeth E. F., Haller-Brem S., Fischer J. A. Regulation of hormone secretion and cytosolic Ca2+ by extracellular Ca2+ in parathyroid cells and C-cells: role of voltage-sensitive Ca2+ channels. Arch Biochem Biophys. 1988 Aug 15;265(1):128–135. doi: 10.1016/0003-9861(88)90378-5. [DOI] [PubMed] [Google Scholar]
  24. Nemeth E. F., Scarpa A. Rapid mobilization of cellular Ca2+ in bovine parathyroid cells evoked by extracellular divalent cations. Evidence for a cell surface calcium receptor. J Biol Chem. 1987 Apr 15;262(11):5188–5196. [PubMed] [Google Scholar]
  25. Ozawa S. Biphasic effect of thyrotropin-releasing hormone on membrane K+ permeability in rat clonal pituitary cells. Brain Res. 1981 Mar 23;209(1):240–244. doi: 10.1016/0006-8993(81)91188-4. [DOI] [PubMed] [Google Scholar]
  26. Ozawa S., Sand O. Electrophysiology of excitable endocrine cells. Physiol Rev. 1986 Oct;66(4):887–952. doi: 10.1152/physrev.1986.66.4.887. [DOI] [PubMed] [Google Scholar]
  27. Penner R., Matthews G., Neher E. Regulation of calcium influx by second messengers in rat mast cells. Nature. 1988 Aug 11;334(6182):499–504. doi: 10.1038/334499a0. [DOI] [PubMed] [Google Scholar]
  28. Sand O., Jonsson L., Nielsen M., Holm R., Gautvik K. M. Electrophysiological properties of calcitonin-secreting cells derived from human medullary thyroid carcinoma. Acta Physiol Scand. 1986 Feb;126(2):173–179. doi: 10.1111/j.1748-1716.1986.tb07803.x. [DOI] [PubMed] [Google Scholar]
  29. Sand O., Ozawa S., Gautvik K. M. Sodium and calcium action potentials in cells derived from a rat medullary thyroid carcinoma. Acta Physiol Scand. 1981 Jul;112(3):287–291. doi: 10.1111/j.1748-1716.1981.tb06818.x. [DOI] [PubMed] [Google Scholar]
  30. Sand O., Ozawa S., Hove K. Electrophysiology of cultured parathyroid cells from the goat. Acta Physiol Scand. 1981 Sep;113(1):45–50. doi: 10.1111/j.1748-1716.1981.tb06859.x. [DOI] [PubMed] [Google Scholar]
  31. Schlegel W., Winiger B. P., Mollard P., Vacher P., Wuarin F., Zahnd G. R., Wollheim C. B., Dufy B. Oscillations of cytosolic Ca2+ in pituitary cells due to action potentials. Nature. 1987 Oct 22;329(6141):719–721. doi: 10.1038/329719a0. [DOI] [PubMed] [Google Scholar]
  32. Shoback D. M., Membreno L. A., McGhee J. G. High calcium and other divalent cations increase inositol trisphosphate in bovine parathyroid cells. Endocrinology. 1988 Jul;123(1):382–389. doi: 10.1210/endo-123-1-382. [DOI] [PubMed] [Google Scholar]
  33. Yellen G. Single Ca2+-activated nonselective cation channels in neuroblastoma. Nature. 1982 Mar 25;296(5855):357–359. doi: 10.1038/296357a0. [DOI] [PubMed] [Google Scholar]
  34. Zeytinoğlu F. N., Gagel R. F., Tashjian A. H., Jr, Hammer R. A., Leeman S. E. Regulation of neurotensin release by a continuous line of mammalian C-cells: the role of biogenic amines. Endocrinology. 1983 Apr;112(4):1240–1246. doi: 10.1210/endo-112-4-1240. [DOI] [PubMed] [Google Scholar]

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

RESOURCES