Abstract:

Potassium channels, which are the most diverse group of the ion channel family, play an important role in the repolarization of cardiomyocytes. Recent studies showed that potassium channels, such as KCNQ and HERG/eag, play an important role in regulating adult heart function through shaping the action potential and maintaining the rhythm of cardiac contraction. The potassium channel protein Shaker is the first voltage-gated potassium channel found in Drosophila to maintain the electrical excitability of neurons and muscle cells, but its role in adult cardiac function is still unclear. In this study, Drosophila was used as a model to study the role of Shaker channel in the maintenance of cardiac function under stress and aging. The incidence of heart failure was observed in shaker mutant after external electrical pacing, which simulates cardiac stress. Additionally, The cardiac-specific driver hand4.2 Gal4 was used to specifically knock down the expression of the potassium channel shaker in Drosophila. The cardiac parameter was analyzed at 1, 3, 5 weeks of age on cardiac specific knockdown of shaker using Drosophila adult cardiac physiological assay. The results showed that the mutation of shaker gene seriously affect the cardiac function under stress, demonstrated by significant increase in heart failure rate under electrical stimulation. In addition, cardiac specific knockdown of shaker increased the incidence of arrhythmias in Drosophila at the age of 5 weeks. Cardiac-specific knockdown of shaker reduces life span. Therefore, the results of this study suggest a vital role of the potassium channel shaker in maintaining normal cardiac function during aging.

Key words: potassium channel, arrhythmias, Shaker, cardiac aging, Drosophila