[Inhibition of salicylate on voltage-gated sodium channels in rat inferior colliculus neurons].
OBJECTIVE
To investigate the mechanism of the tinnitus inducer, sodium salicylate, on voltage-gated sodium channels.


METHODS
The effects of salicylate on voltage-gated sodium channels in freshly dissociated inferior colliculus neurons of rats were studied, using the whole-cell voltage clamp method.


RESULTS
Salicylate blocked sodium current (INa) in concentration-dependent manner (0.1-10 mmol/L). The IC50 value for the blocking action of salicylate was 1.43 mmol/L. Salicylate did not affect the conductance-voltage curve and the steady-state activation curve of INa. The steady-state INa inactivation curve of INa was shifted by about 9 mV in the hyperpolarizing direction. In addition, salicylate delayed the sodium channel recovery from INa inactivation by increasing the slow time constant.


CONCLUSIONS
Our results suggest that salicylate causes a concentration-dependent blockade of INa and shifts the INa inactivation curve to more hyperpolarized potentials, which could be related to the mechanism of salicylate-induced tinnitus.
Liu
Yanxing
Y
Department of Otorhinolaryngology, Peking University Third Hospital, Beijing, China.
Li
Xuepei
X
Zhang
Hailin
H
Wang
Yongli
Y
Lu
Hong
H
Qi
Xiang
X
Zhang
Huijun
H
D000818:Animals; D007245:Inferior Colliculi / Q000166:cytology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000187:drug effects* / Q000378:metabolism; D012980:Sodium Salicylate / Q000494:pharmacology*
D015222:Sodium Channels; D012980:Sodium Salicylate