NDLI: Differential modulation of voltage-dependent Ca2+ currents by EGTA and BAPTA in bovine adrenal chromaffin cells

Content Provider	Springer Nature Link
Author	Bödding, M. Penner, R.
Abstract	Whole-cell patch-clamp recordings were made to examine the effects of the Ca2+ chelators EGTA and BAPTA on the biophysical properties of voltage-operated Ca2+ currents in bovine adrenal chromaffin cells. Ca2+ currents in the presence of either EGTA or BAPTA over a concentration range of 0.1–60 mM were recorded under otherwise identical conditions. Analysis of current-voltage relationships yielded unexpected differences in several important parameters such as the voltage dependence of activation, kinetics, slope, and reversal potential, which seemed to be unrelated to the Ca2+-binding properties of these chelators. Increasing concentrations of BAPTA augmented the peak Ca2+ current amplitude while current amplitudes in the presence of EGTA remained constant over the entire concentration range tested. Increasing concentrations of BAPTA shifted the voltage sensitivity of Ca2+ currents by about 15 mV towards positive voltages. EGTA, over the same concentration range, did not affect the voltage sensitivity. The shift in voltage sensitivity observed with BAPTA was unrelated to its faster Ca2+-binding kinetics, as it was also observed when substituting Ca2+ with Ba2+ as the charge carrier. The mechanism by which BAPTA affects Ca2+ channel voltage dependence also seems unrelated to kinase-mediated modulation of Ca2+ channels, since the protein-kinase-C- (PKC-) specific drugs bisindolylmaleimide and phorbol ester (PMA) neither mimicked nor prevented the action of BAPTA. The less specific kinase inhibitor staurosporine, however, augmented Ca2+ currents similarly to BAPTA, but without affecting the voltage sensitivity. The BAPTA-mediated shift in voltage sensitivity was partially suppressed by non-hydrolysable analogs of GTP (GDP[β-S] and GTP[γ-S]). Lowering [Mg2+]i mimicked the BAPTA-induced shift in voltage sensitivity and prevented further shifts in voltage sensitivity by BAPTA. The results demonstrate that BAPTA and EGTA, despite their similarities in terms of Ca2+ buffering, have disparate effects on the voltage dependence of Ca2+ channels and careful selection of the chelator is required to quantitatively assess Ca2+ currents.
Starting Page	27
Ending Page	38
Page Count	12
File Format	PDF
ISSN	00316768
Journal	Pflügers Archiv
Volume Number	439
Issue Number	1-2
e-ISSN	14322013
Language	English
Publisher	Springer-Verlag
Publisher Date	1999-10-13
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Content Type	Text
Resource Type	Article
Subject	Physiology Physiology (medical) Clinical Biochemistry

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Differential modulation of voltage-dependent Ca2+ currents by EGTA and BAPTA in bovine adrenal chromaffin cells

Ca2+-channel-dependent and -independent inhibition of exocytosis by extracellular ATP in voltage-clamped rat adrenal chromaffin cells

Pharmacological and biophysical properties of Ca2+ channels and subtype distributions in human adrenal chromaffin cells

Two types of ω-agatoxin IVA-sensitive Ca2+ channels are coupled to adrenaline and noradrenaline release in bovine adrenal chromaffin cells

Autocrine/paracrine modulation of calcium channels in bovine chromaffin cells

Extracellular ATP regulates exocytosis by inhibiting multiple Ca2+ channel types in bovine chromaffin cells

Modulation of spontaneous intracellular Ca2+ fluctuations and spontaneous cholinergic transmission in rat chromaffin cells in situ by endogenous GABA acting on GABAA receptors

Intracellular Mg2+ hyperpolarizes rabbit coronary artery smooth muscle cells by differential modulation of Ca2+ i-dependent ion channels

Calcium channel subtypes in porcine adrenal chromaffin cells

Differential modulation of voltage-dependent Ca2+ currents by EGTA and BAPTA in bovine adrenal chromaffin cells

Similar Documents

Differential modulation of voltage-dependent Ca2+ currents by EGTA and BAPTA in bovine adrenal chromaffin cells

Ca2+-channel-dependent and -independent inhibition of exocytosis by extracellular ATP in voltage-clamped rat adrenal chromaffin cells

Pharmacological and biophysical properties of Ca2+ channels and subtype distributions in human adrenal chromaffin cells

Two types of ω-agatoxin IVA-sensitive Ca2+ channels are coupled to adrenaline and noradrenaline release in bovine adrenal chromaffin cells

Autocrine/paracrine modulation of calcium channels in bovine chromaffin cells

Extracellular ATP regulates exocytosis by inhibiting multiple Ca2+ channel types in bovine chromaffin cells

Modulation of spontaneous intracellular Ca2+ fluctuations and spontaneous cholinergic transmission in rat chromaffin cells in situ by endogenous GABA acting on GABAA receptors

Intracellular Mg2+ hyperpolarizes rabbit coronary artery smooth muscle cells by differential modulation of Ca2+ i-dependent ion channels

Calcium channel subtypes in porcine adrenal chromaffin cells

Differential modulation of voltage-dependent Ca2+ currents by EGTA and BAPTA in bovine adrenal chromaffin cells