Enhancement of the Shaker B delta6-46 current by fatty acids depends on the activation of the lipoxygenase metabolic pathway.

Voltage-gated K+ channels are modulated by extracellular free unsaturated fatty acids. Both increases and attenuations of K+ channels activities have been observed. We studied the effect of cis-unsaturated fatty acids on Shaker B delta6-46 and the endogenous outward rectifier K+ channels expressed in COS cell line, using the whole cell recording technique. For both K+ channels, exogenously applied unsaturated fatty acids dramatically increased the outward K+ currents. This enhancement was not mediated by cylooxygenase or epoxygenase (P450) enzymes. However, nordihydroguaiaretic acid, a lipoxygenase metabolic pathway blocker, did prevent the arachidonic acid-induced Shaker current enhancement.