Am J Physiol Cell Physiol AJP: Gastrointestinal and Liver Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 278: C667-C675, 2000;
0363-6143/00 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (10)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Callamaras, N.
Right arrow Articles by Parker, I.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Callamaras, N.
Right arrow Articles by Parker, I.
Vol. 278, Issue 4, C667-C675, April 2000

Ca2+-dependent activation of Clminus currents in Xenopus oocytes is modulated by voltage

Nick Callamaras and Ian Parker

Laboratory of Cellular and Molecular Neurobiology, Department of Neurobiology and Behavior, University of California Irvine, Irvine, California 92697-4550

Ca2+-activated Cl- currents (ICl,Ca) were examined using fluorescence confocal microscopy to monitor intracellular Ca2+ liberation evoked by flash photolysis of caged inositol 1,4,5-trisphosphate (InsP3) in voltage-clamped Xenopus oocytes. Currents at +40 mV exhibited a steep dependence on InsP3 concentration ([InsP3]), whereas currents at -140 mV exhibited a higher threshold and more graded relationship with [InsP3]. Ca2+ levels required to half-maximally activate ICl,Ca were about 50% larger at -140 mV than at +40 mV, and currents evoked by small Ca2+ elevations were reduced >25-fold. The half-decay time of Ca2+ signals shortened at increasingly positive potentials, whereas the decay of ICl,Ca lengthened. The steady-state current-voltage (I-V) relationship for ICl,Ca exhibited outward rectification with weak photolysis flashes but became more linear with stronger stimuli. Instantaneous I-V relationships were linear with both strong and weak stimuli. Current relaxations following voltage steps during activation of ICl,Ca decayed with half-times that shortened from about 100 ms at +10 mV to 20 ms at -160 mV. We conclude that InsP3-mediated Ca2+ liberation activates a single population of Cl- channels, which exhibit voltage-dependent Ca2+ activation and voltage-independent instantaneous conductance.

calcium-activated chloride current; voltage dependence; inositol 1,4,5-trisphosphate


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
L. Ohana, O. Barchad, I. Parnas, and H. Parnas
The Metabotropic Glutamate G-protein-coupled Receptors mGluR3 and mGluR1a Are Voltage-sensitive
J. Biol. Chem., August 25, 2006; 281(34): 24204 - 24215.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
S. H. Boese, O. Aziz, N. L. Simmons, and M. A. Gray
Kinetics and regulation of a Ca2+-activated Cl- conductance in mouse renal inner medullary collecting duct cells
Am J Physiol Renal Physiol, April 1, 2004; 286(4): F682 - F692.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
P. S. Mischel, J. A. Umbach, S. Eskandari, S. G. Smith, C. B. Gundersen, and G. A. Zampighi
Nerve Growth Factor Signals via Preexisting TrkA Receptor Oligomers
Biophys. J., August 1, 2002; 83(2): 968 - 976.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
T. L. Pallone and J. M.-C. Huang
Control of descending vasa recta pericyte membrane potential by angiotensin II
Am J Physiol Renal Physiol, June 1, 2002; 282(6): F1064 - F1074.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online