Salicylate blocks L-type calcium channels in rat inferior colliculus neurons

To investigate the effects of the tinnitus inducer sodium salicylate on L-type voltage-gated calcium channels, we studied freshly dissociated inferior colliculus neurons of rats by the whole-cell voltage clamp method. Salicylate's blocking of L-type calcium channels was concentration dependent, and the IC50 value of salicylate was estimated to be 1.99 mM. An amount of 1 mM salicylate significantly shifted the steady-state inactivation curve of L-type calcium channels about 9 mV in the hyperpolarizing direction and significantly delayed calcium channel recovery. Our results suggest that salicylate's blocking of L-type calcium channels may contribute to salicylate-induced tinnitus by decreasing GABA release in the inferior colliculus.