[Inhibition of salicylate on potassium channels in rat inferior colliculus neurons].
OBJECTIVE
To understand what role of the transient outward potassium channels and the delayed rectifier potassium channels play in the mechanism of salicylate-induced tinnitus.


METHODS
The effects of salicylate on the transient outward potassium channels and the delayed rectifier potassium channels in freshly dissociated inferior colliculus neurons of rats were studied, using the whole-cell voltage clamp method.


RESULTS
Salicylate blocked the transient outward potassium current (I(K(A and the delayed rectifier potassium current (I(K(DR in concentration-dependent manner (0.1-1 mmol/L). The IC50 values for the blocking action of salicylate on I(K(A)) and I(K(DR)) were 2.27 and 0.80 mmol/L, respectively. At a concentration of 1 mmol/L, salicylate did not shift the activation and inactivation curves of I(K(A)), but significantly shifted the activation and inactivation curves of I(K(DR)) negatively by approximately 11 mV and 24 mV.


CONCLUSIONS
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)). Effects of I(K(A)) and I(K(DR)), especially I(K(DR)), by salicylate may play an important role in salicylate-induced tinnitus.
Liu
Yan-xing
YX
Department of Otorhinolaryngology, Third affiliated Hospital,Peking University, Beijing 100083, China. drlixuepei@sohu.com
Li
Xue-pei
XP
Liu
Jun-xiu
JX
Shi
Ge-ming
GM
Lu
Hong
H
Ma
Chang-sheng
CS
D000818:Animals; D051668:Delayed Rectifier Potassium Channels / Q000187:drug effects; D007245:Inferior Colliculi / Q000166:cytology / Q000187:drug effects*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012459:Salicylates / Q000494:pharmacology*
D051668:Delayed Rectifier Potassium Channels; D015221:Potassium Channels; D012459:Salicylates