The Journal of General Physiology, Vol 104, 395-422, Copyright © 1994 by The Rockefeller University Press

ARTICLES

Simultaneous measurement of Ca2+ release and influx into smooth muscle cells in response to caffeine. A novel approach for calculating the fraction of current carried by calcium

A Guerrero, JJ Singer and FS Fay
Department of Physiology, University of Massachusetts Medical School, Worcester 01655.

Activation of ryanodine receptors on the sarcoplasmic reticulum of single smooth muscle cells from the stomach muscularis of Bufo marinus by caffeine is accompanied by a rise in cytoplasmic [Ca2+] ([Ca2+]i), and the opening of nonselective cationic plasma membrane channels. To understand how each of these pathways contributes to the rise in [Ca2+]i, one needs to separately monitor Ca2+ entry through them. Such information was obtained from simultaneous measurements of ionic currents and [Ca2+]i by the development of a novel and general method to assess the fraction of current induced by an agonist that is carried by Ca2+. Application of this method to the currents induced in these smooth muscle cells by caffeine revealed that approximately 20% of the current passing through the membrane channels activated following caffeine application is carried by Ca2+. Based on this information we found that while Ca2+ entry through these channels rises slowly, release of Ca2+ from stores, while starting at the same time, is much faster and briefer. Detailed quantitative analysis of the Ca2+ release from stores suggests that it most likely decays due to depletion of Ca2+ in those stores. When caffeine was applied twice to a cell with only a brief (30 s) interval in between, the amount of Ca2+ released from stores was markedly diminished following the second caffeine application whereas the current carried in part by Ca2+ entry across the plasma membrane was not significantly affected. These and other studies described in the preceding paper indicate that activation of the nonselective cation plasma membrane channels in response to caffeine was not caused as a consequence of emptying of internal Ca2+ stores. Rather, it is proposed that caffeine activates these membrane channels either by direct interaction or alternatively by a linkage between ryanodine receptors on the sarcoplasmic reticulum and the nonselective cation channels on the surface membrane.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. Wray and T. Burdyga Sarcoplasmic Reticulum Function in Smooth Muscle Physiol Rev, January 1, 2010; 90(1): 113 - 178. [Abstract] [Full Text] [PDF]

				G. C. Amberg, M. F. Navedo, M. Nieves-Cintron, J. D. Molkentin, and L. F. Santana Calcium sparklets regulate local and global calcium in murine arterial smooth muscle J. Physiol., February 15, 2007; 579(1): 187 - 201. [Abstract] [Full Text] [PDF]

				H. Zou, L. M. Lifshitz, R. A. Tuft, K. E. Fogarty, and J. J. Singer Using Total Fluorescence Increase (Signal Mass) to Determine the Ca2+ Current Underlying Localized Ca2+ Events J. Gen. Physiol., September 1, 2004; 124(3): 259 - 272. [Abstract] [Full Text] [PDF]

				Y.-X. Wang, Y.-M. Zheng, Q.-B. Mei, Q.-S. Wang, M. L. Collier, S. Fleischer, H.-B. Xin, and M. I. Kotlikoff FKBP12.6 and cADPR regulation of Ca2+ release in smooth muscle cells Am J Physiol Cell Physiol, March 1, 2004; 286(3): C538 - C546. [Abstract] [Full Text]

				R. E. Hoesch, D. Weinreich, and J. P. Y. Kao A Novel Ca2+ Influx Pathway in Mammalian Primary Sensory Neurons Is Activated by Caffeine J Neurophysiol, July 1, 2001; 86(1): 190 - 196. [Abstract] [Full Text] [PDF]

				C White and J G McGeown Regulation of basal intracellular calcium concentration by the sarcoplasmic reticulum in myocytes from the rat gastric antrum J. Physiol., December 1, 2000; 529(2): 395 - 404. [Abstract] [Full Text] [PDF]

				M. T Kirber, A. Guerrero-Hernandez, D. S Bowman, K. E Fogarty, R. A Tuft, J. J Singer, and F. S Fay Multiple pathways responsible for the stretch-induced increase in Ca2+ concentration in toad stomach smooth muscle cells J. Physiol., April 1, 2000; 524(1): 3 - 17. [Abstract] [Full Text] [PDF]

				T Kamishima, N W Davies, and N B Standen Mechanisms that regulate [Ca2+]i following depolarization in rat systemic arterial smooth muscle cells J. Physiol., January 15, 2000; 522(2): 285 - 295. [Abstract] [Full Text] [PDF]

				H. Zou, L. M. Lifshitz, R. A. Tuft, K. E. Fogarty, and J. J. Singer Imaging Ca2+ Entering the Cytoplasm through a Single Opening of a Plasma Membrane Cation Channel J. Gen. Physiol., October 1, 1999; 114(4): 575 - 588. [Abstract] [Full Text] [PDF]

				A. A Gutierrez, J. M. Arias, L. Garcia, J. Mas-Oliva, and A. Guerrero-Hernandez Activation of a Ca2+-permeable cation channel by two different inducers of apoptosis in a human prostatic cancer cell line J. Physiol., May 15, 1999; 517(1): 95 - 107. [Abstract] [Full Text] [PDF]

				S. J. Kim, E.-M. Koh, T. M. Kang, Y. C. Kim, I. So, G. Isenberg, and K. W. Kim Ca2+ influx through carbachol-activated non-selective cation channels in guinea-pig gastric myocytes J. Physiol., December 15, 1998; 513(3): 749 - 760. [Abstract] [Full Text] [PDF]

				A V Shmigol, D A Eisner, and S. Wray Properties of voltage-activated [Ca2+]i transients in single smooth muscle cells isolated from pregnant rat uterus J. Physiol., September 15, 1998; 511(3): 803 - 811. [Abstract] [Full Text] [PDF]

				M. J Taggart and S. Wray Contribution of sarcoplasmic reticular calcium to smooth muscle contractile activation: gestational dependence in isolated rat uterus J. Physiol., August 15, 1998; 511(1): 133 - 144. [Abstract] [Full Text] [PDF]

				H. KURIYAMA, K. KITAMURA, T. ITOH, and R. INOUE Physiological Features of Visceral Smooth Muscle Cells, With Special Reference to Receptors and Ion Channels Physiol Rev, July 1, 1998; 78(3): 811 - 920. [Abstract] [Full Text] [PDF]

				W. F. Jackson and K. L. Blair Characterization and function of Ca2+-activated K+ channels in arteriolar muscle cells Am J Physiol Heart Circ Physiol, January 1, 1998; 274(1): H27 - H34. [Abstract] [Full Text] [PDF]

				S. J. Kim, S. C. Ahn, J. K. Kim, Y. C. Kim, I. So, and K. W. Kim Changes in intracellular Ca2+ concentration induced by L-type Ca2+ channel current in guinea pig gastric myocytes Am J Physiol Cell Physiol, December 1, 1997; 273(6): C1947 - C1956. [Abstract] [Full Text] [PDF]

				H. Karaki, H. Ozaki, M. Hori, M. Mitsui-Saito, K.-I. Amano, K.-I. Harada, S. Miyamoto, H. Nakazawa, K.-J. Won, and K. Sato Calcium Movements, Distribution, and Functions in Smooth Muscle Pharmacol. Rev., June 1, 1997; 49(2): 157 - 230. [Abstract] [Full Text] [PDF]

				C. A. Ufret-Vincenty, A. D. Short, A. Alfonso, and D. L. Gill A Novel Ca[IMAGE] Entry Mechanism Is Turned On during Growth Arrest Induced by Ca[IMAGE] Pool Depletion J. Biol. Chem., November 10, 1995; 270(45): 26790 - 26793. [Abstract] [Full Text] [PDF]

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents