Relaxation in Glycerinated Cardiac Fibers

Publisher Website
Google Scholar
Abstract
Summary The effects of the nonphysio-logical relaxing agents EDTA and EGTA on contraction induced by ATP and magnesium in glycerol extracted dog cardiac fibers were investigated. Both EDTA (2 mM) and EGTA (2 mM) produced a 47% and 35% inhibition of contraction respectively as compared to the maximum tension developed when calcium (2 mM) was subsequently added. It was concluded that since these chelating agents produce a calcium reversible relaxation in glycer mated cardiac fibers, measurements of inhibition of Mg-activated ATPase in cardiac myofibrils under similar conditions is not a model for relaxation as suggested in the literature. Cardiac myofibrils may therefore contain a contaminating Mg-activated ATPase which is not Ca dependent and not associated with contraction.

This publication has 3 references indexed in Scilit: