Steps of temperature jumps relieve inactivation of hERG

The human ether-á-go-go-related K+ channels (hERG) exhibit unique features: fast kinetics of entry/recovery from inactivation and marked inward rectification that is coupled to the pore inactivation that are important for the repolarizing phase of the cardiac action potential. Here, we used an upgraded version of the temperature steps technique using the endogenous melanin of Xenopus laevis oocytes, recently developed by our research group, to study the thermodynamics characteristics of hERG. Using laser pulses, we can modulate the membrane temperature to generate a step temperature jump (T-jump) of 10°C, with a rising phase of 5ms and duration of 134ms, which allows us to resolve the kinetic response to temperature.