Direct inhibitory action of EGTA-Ca complex on reverse-mode Na/Ca exchange in Myxicola giant axons

The Journal of Membrane Biology
R A SjodinJ G Montes

Abstract

Giant axons from the marine annelid Myxicola infundibulum were internally dialyzed with solutions containing 22Na ions as tracers of Na efflux. In experiments performed in Li-substituted seawater, Na efflux that is dependent on external Ca ion concentration, [Ca2+]o, was measured using dialysis to maintain [Na+]i at 100 mM, which enhances the [Ca2+]o-dependent Na efflux component, (i.e., reverse-mode Na/Ca exchange). When dialysis fluid contained EGTA (1 mM) to buffer the internal Ca concentration, [Ca2+]i, to desired levels, Na efflux lost its normal sensitivity to external calcium. The inhibition was not simply due to the Ca-chelating action of EGTA to produce insufficient [Ca2+]i to activate Na/Ca exchange. The addition of EGTA inhibited Cao-dependent Na efflux even when a large enough excess of [Ca2+]i was present to saturate the EGTA and still produce elevated values of [Ca2+]i. Control experiments showed that these high values of [Ca2+]i resulted in normal Na/Ca exchange in the absence of EGTA. It is concluded that the presence of EGTA itself interferes with the manifestation of reverse-mode Na/Ca exchange in Myxicola giant axons.

References

Jul 1, 1976·The Journal of Physiology·P F Baker, P A McNaughton
Jan 1, 1979·The Journal of Membrane Biology·B Forbush
Jan 1, 1979·The Journal of General Physiology·R DiPolo
Apr 1, 1978·The Journal of General Physiology·R A Sjodin, R F Abercrombie
Jun 1, 1977·The Journal of General Physiology·R F Abercrombie, R A Sjodin
Jul 24, 1975·The Journal of Membrane Biology·M P Blaustein, J M Russell
May 1, 1987·The American Journal of Physiology·H Rasgado-Flores, M P Blaustein
Feb 1, 1969·The Journal of Physiology·P F BakerR A Steinhardt
Nov 1, 1967·The Journal of General Physiology·F J Brinley, L J Mullins
Oct 1, 1981·The Journal of General Physiology·R F AbercrombieD Livengood

❮ Previous
Next ❯

Citations

Sep 1, 1992·Journal of Neuroscience Methods·A R Kay
Jun 1, 1991·Current Opinion in Neurobiology·R J Perry, P A McNaughton
Aug 4, 2007·Progress in Neurobiology·Tamás L Török
Nov 12, 2005·The Journal of Primary Prevention·Martica L Bacallao, Paul R Smokowski
Apr 11, 2008·Physiology·György Szabadkai, Michael R Duchen
Jul 3, 1999·Physiological Reviews·M P Blaustein, W J Lederer

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.