Purkinje fibre isolation

Blaustein MP, Golovina VA 2001 Structural complexity and functional diversity of endoplasmic reticulum Ca2+ stores. Trends Neurosci 24 602-608 Boyett MR, Hart G, Levi A J 1986 Dissociation between force and intracellular sodium activity with strophanthidin in isolated sheep Purkinje fibres. J Physiol 381 311—331... 

More recent studies continue to support the unique antifibrillatory activity of bretylium. Kowey et al. [38] have shown that bretylium prevented spontaneous VF and decreased the effects on VF threshold in a feline myocardial infarction model. They attributed this beneficial effect to a decrease in the dispersion of refractoriness between normal and ischaemic regions of the heart. In contrast, clofilium (14, see below), which had little effect on dispersion of refractoriness after coronary occlusion, was unable to prevent spontaneous VF. Similar results were seen in isolated tissue studies with canine subendocardial Purkinje fibres and ventricular muscle which contained both normal and ischaemic regions [39]. In these studies bretylium caused a smaller increase in dispersion of refractoriness in subendocardial Purkinje fibres than either sotalol or clofilium. In ventricular muscle tissue, bretylium decreased dispersion while sotalol and clofilium increased dispersion of refractoriness. 

Boyett, M. R., Hart, G., Levi, A. J. and Roberts, A. Effects of repetitive activity on developed force and intracellular sodium in isolated sheep and dog Purkinje fibres. Journal of Physiology 1987, 388 295-322. 

Prediction of the risk of Torsade de Pointes using the model of isolated canine Purkinje fibres. Br J Pharmacol 144(3) 376-385... 

There are comparatively few reports concerned with the stereoselective pharmacodynamics and pharmacokinetics of flecainide enantiomers. In vivo studies have revealed equipotency and equiactivity for the two enantiomers in mouse and dog models of arrhythmia. In vitro tests on canine Purkinje fibres have also shown that the enantiomers have comparable electrophysiologic activities. The two enantiomers have also shown similar affinities to a receptor site associated with cardiac sodium channels in isolated rat cardiac myocytes. ... 

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