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Updated: Aug 13, 2026
Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption
Published on: August 16, 2016
Cardiac muscle function following chronic dietary potassium depletion in the rabbit
1Department of Medicine, United Medical School, London.
Study Objective:
The aim was to investigate a possible defect in cardiac muscle contractile performance following chronic K+ depletion.
Design:
Cardiac muscle force development, membrane potential, and action potential configuration were measured in isolated superfused right ventricular papillary muscles or trabeculae from control or K+ depleted NZW rabbits. The effects of adrenaline, strophanthidin, and changes in external [Ca2+] and [K+] were investigated.
Experimental Materials:
Experiments were performed on 50 adult NZW rabbits, average weight 2.3 kg, which were fed either a control diet (n = 25), or a K+ deficient diet (n = 25) for 25 d.
Measurements And Main Results:
There was a significant reduction in contractile force in preparations from the K+ depleted group compared to those from control animals. This was associated with an increased positive inotropic response to low [K+], but an apparent reduction in response to adrenaline. There was no significant difference between groups as to the effect of strophanthidin.
Conclusions:
It is suggested that the reduction in response to adrenaline reflects a down regulation in beta receptor density, due to an increased level of circulating catecholamines, and that the defect in myocardial function is a result of adaptive changes to Ca2+ handling mechanisms within the cell.
