The Effects of Exogenous Calcium Buffers on the Systolic Calcium Transient in Rat Ventricular Myocytes

The aim of this work was to characterize the effects that two commonly used “caged” calcium buffers (NP-EGTA and nitr-5) have on the amplitude and time course of decay of the calcium transient. We made quantitative measurements of both free and total calcium using the measured buffering properties o...

Full description

Saved in:
Bibliographic Details
Published in:Biophysical journal 2001-04, Vol.80 (4), p.1915-1925
Main Authors: Díaz, M.E., Trafford, A.W., Eisner, D.A.
Format: Article
Language:English
Subjects:
Aniline Compounds - pharmacology
Animals
Biology
Caffeine - pharmacology
Calcium
Calcium - metabolism
Calcium - pharmacology
Cells, Cultured
Central Nervous System Stimulants - pharmacology
Chelating Agents - pharmacology
Dose-Response Relationship, Drug
Egtazic Acid - analogs & derivatives
Egtazic Acid - metabolism
Egtazic Acid - pharmacology
Light
Models, Chemical
Muscles - cytology
Muscles - metabolism
Myocardium - cytology
Patch-Clamp Techniques
Photolysis
Rats
Rodents
Sarcoplasmic Reticulum - metabolism
Xanthenes - pharmacology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The aim of this work was to characterize the effects that two commonly used “caged” calcium buffers (NP-EGTA and nitr-5) have on the amplitude and time course of decay of the calcium transient. We made quantitative measurements of both free and total calcium using the measured buffering properties of the cell. Intracellular calcium concentration ([Ca 2+] i) was measured with fluo-3 in rat ventricular myocytes. Incorporation of the buffer NP-EGTA decreased both the amplitude and rate of decay of the caffeine response. The slowing could be quantitatively accounted for by the measured increased buffering. These effects were removed by photolysis of NP-EGTA. Similar results were obtained with nitr-5 except that the effects were not completely removed by photolysis. This was shown to be due to the persistence of a component of the increased buffering after photolysis. Both buffers decreased the amplitude of the systolic calcium transient. However, although nitr-5 produced a simple slowing of the decay, NP-EGTA resulted in an initial rapid phase of decay. This rapid phase of decay is attributed to calcium binding to NP-EGTA. This work represents the first quantitative analysis of the effects that extra buffering by a fast and a slow calcium chelator may have on the calcium transient.
ISSN:0006-3495
1542-0086
DOI:10.1016/S0006-3495(01)76161-9