[Effect of cisplatin on the potassium channels of spiral ganglion neurons from neonatal rats].
OBJECTIVE
To investigate the effect of cisplatin on outward delayed rectifier potassium currents (IKDR currents) in isolated spiral ganglion neurons cells and to analyze possible intracellular mechanism of this effects by using the patch-clamp technique.


METHODS
The IKDR was recorded and measured before and after the application of 10 micromol/L cisplatin in external solution by using the whole cell patch-clamp technique.


RESULTS
Cisplatin could inhibit SGNs voltage-dependent potassium channels, the zero current potential and reversal potential of IKDR currents were both shift to polarizing directions by 10 micromol/L cisplatin. Moreover, the maximal magnitude of IKDR currents were decreased by 23.3% when giving the test pulse at +50 mV. Cisplatin's inhibition on IKDR has dose-dependence with cisplatin-concentration in extracellular fluid and the currents recovered completely after cisplatin being washed out.


CONCLUSIONS
This research explained the toxic mechanism of cisplatin through its action on keeping from spiral ganglion neuron's IKDR from the electrophysiological aspect and set a foundation for further research.
Xiao
Hongjun
H
Department of Otolaryngology, Union Hospital, Huazhong University of Science and Technology, Wuhan, China. xhongjunent@yahoo.com.cn
Ma
Zhiyue
Z
Jiang
Yuanming
Y
D000818:Animals; D000831:Animals, Newborn; D002945:Cisplatin / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013136:Spiral Ganglion / Q000166:cytology / Q000187:drug effects*
D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D002945:Cisplatin