The study, published in the leading journal
Circulation Research, found that long-term training in both horses and mice caused a reduction in key proteins, known as ion channels, that control AV node conduction.
The expression and activity of the ion channels were then investigated in detail in mice that followed a program which modelled long-term exercise training to build their fitness.
The mice were used to explore mechanisms underlying heart block in detail using approaches that would not be possible in racehorses.
Training-induced heart block and underlying ion channel changes were reversible when the exercise was stopped or when mice were given a compound known as an anti-microRNA.
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