Effects of salicylate on transient outward and delayed rectifier potassium channels in rat inferior colliculus neurons.

The effects of salicylate (a tinnitus inducer) were studied on the transient outward potassium current (I(K(A))) and the delayed rectifier potassium current (I(K(DR))) in acutely dissociated rat inferior colliculus neurons by the whole-cell voltage-clamp method. Salicylate's inhibition of the amplitude of I(K(A)) and I(K(DR)) was concentration-dependent. The IC(50) values for the blocking action of salicylate on I(K(A)) and I(K(DR)) were 2.27 and 0.80 mM, respectively. At a concentration of 1 mM, salicylate significantly shifted the activation and inactivation curves of I(K(DR)) negatively by approximately 11 and 24 mV, respectively, but did not shift the I(K(A)) curves. In conclusion, salicylate inhibits both I(K(A)) and I(K(DR)) in rat inferior colliculus neurons but only significantly affects the activation and inactivation kinetics of I(K(DR)). Depression of I(K(DR)) by salicylate may play an important role in salicylate-induced tinnitus.