Effects of oxidants on the sarcoplasmic reticulum of saponin treated rat ventricular trabeculae

MacFarlane, N.G., Miller, D.J., Smith, G.L. and Steele, D.S. (1994) Effects of oxidants on the sarcoplasmic reticulum of saponin treated rat ventricular trabeculae. Cardiovascular Research, 28(11), pp. 1647-1652. (doi:10.1093/cvr/28.11.1647) (PMID:7842458)

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Abstract

Objective: The aim was to determine the effects of the superoxide anion, hydrogen peroxide, and hypochlorous acid on in situ cardiac sarcoplasmic reticulum. Methods: Simultaneous measurement of caffeine induced calcium release from the sarcoplasmic reticulum and subsequent myofilament tension generation was made on saponin permeabilised rat ventricular trabeculae before, during, and after exposure to various reactive oxygen species. The superoxide anion (O2.−) was generated using the xanthine-xanthine oxidase system, hypochlorous acid (HOC1) was prepared from NaOCl, and hydrogen peroxide (H2O2) was added from a 30% stock solution. Results: At [O2.−] sufficient to abolish tension generation by the myofilaments completely, the associated caffeine induced calcium release was unaffected. Both H2O2 and HOC1 diminished caffeine induced calcium release but had differential effects on the associated tension response. Exposure to HOC1 favoured the occurrence of spontaneous calcium releases from the sarcoplasmic reticulum. Conclusions: The reactive oxygen species H2O2 and HOC1 reduced the amount of calcium release from the sarcoplasmic reticulum while O2.− was without effect. In some preparations it was observed that HOC1 favoured spontaneous calcium release which might additionally reduce the calcium content of the sarcoplasmic reticulum.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Miller, Dr David and Smith, Professor Godfrey and MacFarlane, Professor Niall
Authors: MacFarlane, N.G., Miller, D.J., Smith, G.L., and Steele, D.S.
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Cardiovascular Research
Publisher:Oxford University Press
ISSN:0008-6363
ISSN (Online):1755-3245

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