Am J Physiol Cell Physiol Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 257: C865-C874, 1989;
0363-6143/89 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
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 Google Scholar
Google Scholar
Right arrow Articles by Stutzin, A.
Right arrow Articles by Rojas, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Stutzin, A.
Right arrow Articles by Rojas, E.

AJP - Cell Physiology, Vol 257, Issue 5 C865-C874, Copyright © 1989 by American Physiological Society

ARTICLES

Characteristics of two types of calcium channels in rat pituitary gonadotrophs

A. Stutzin, S. S. Stojilkovic, K. J. Catt and E. Rojas
Laboratory of Cell Biology and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.

The properties of Ca2+ channels in cultured rat pituitary gonadotrophs were analyzed by the patch-clamp technique. The inward Ca2+ currents, recorded in the presence of 5.2 mM Ca2+ or Ba2+, included a fast, transient component with activation-inactivation kinetics and a delayed component with slower activation. The midpoint of the activation curve lay at -30 mV for the transient component and at -12 mV for the delayed component. At the midpoint, changes in potential of 9.5 and 13 mV induced an e-fold change in the activation of the transient and delayed components, respectively. The rate of inactivation of the first component was strongly voltage dependent. At -43 mV, a 7.4-mV change in potential induced an e-fold change in the fraction of Ca2+ channels available to conduct Ca2+ current. During long-lasting (100-200 ms) low-frequency depolarizing voltage-clamp pulses, the size of the delayed component of the Ca2+ current remained constant. The differential effects of membrane potential on inactivation and the different time constants for activation of the two components of the Ca2+ conductance indicate the presence of two types of Ca2+ channels in the membrane of the gonadotroph: the rapidly inactivating current appears to be attributable to a T-type channel, and the noninactivating current corresponds to the L-type channel described in many other cell types.


This article has been cited by other articles:


Home page
 Physiol. Rev.Home page
E. Perez-Reyes
Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels
Physiol Rev, January 1, 2003; 83(1): 117 - 161.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
R. Vinet and F. F. Vargas
L- and T-type voltage-gated Ca2+ currents in adrenal medulla endothelial cells
Am J Physiol Heart Circ Physiol, April 1, 1999; 276(4): H1313 - H1322.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
J. VANECEK
Cellular Mechanisms of Melatonin Action
Physiol Rev, July 1, 1998; 78(3): 687 - 721.
[Abstract] [Full Text] [PDF]


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