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Effects of acute hypoxia on potassium channels in spiral ganglion cells of SD rats / 中华耳鼻咽喉头颈外科杂志
Chinese Journal of Otorhinolaryngology Head and Neck Surgery ; (12): 823-828, 2015.
Article in Chinese | WPRIM | ID: wpr-243866
ABSTRACT
<p><b>OBJECTIVE</b>The present study was to investigate the effects of acute hypoxia on the electrophysiological properties and outward current of spiral ganglion cell (SGC).</p><p><b>METHODS</b>SGC of newborn's Sprague Dawley (SD) rats were isolated and digested, primary cultured neurons for 8 h. By perfusion with physical saline solution containing no glucose and low oxygen, SGNs model of acute hypoxia was established. The whole-cell patch clamp recording was used to clarify the effect of hypoxia on the outward currents of SGC.</p><p><b>RESULTS</b>The outward current of SGC showed characteristics of outward rectification, which contained two major components, one sensitive to the big conductance Ca²⁺-activated K⁺ channels (BKCa) which blocked by TEA, and the other could be suppressed by the KV channel blocker 4-AP. When holding at -60 mV, acute hypoxia increased the outward current of SGC in a voltage-dependent manner, which mainly increased the amplitude of the current activated by the votage ranged from 0 mV to +60 mV, and increased the amplitude of outward current from (1 160.0 ± 129.1) pA to (2 428 ± 239.3) pA (n = 9, P < 0.01) at holding potential of -60mV. By perfusion with the Potassium channel blocker TEA or 4-AP, the former could significantly reduced the increasing of outward currents induced by hypoxia on the SGC, the latter had no significant effect on the outward current increased by the hypoxia.</p><p><b>CONCLUSIONS</b>These results suggest that acute hypoxia causes neuron hyperpolarization possibly by activating big conductance BKCa of the SGC. When the BKca channels are activated, K⁺ effluxes increase, which induces cell membrane hyperpolarization, and decreases cell excitability, which may affect the conducting function of SGC.</p>
Subject(s)
Full text: Available Index: WPRIM (Western Pacific) Main subject: Potassium Channels / Spiral Ganglion / Rats, Sprague-Dawley / Patch-Clamp Techniques / Cell Biology / Hypoxia / Metabolism / Neurons Type of study: Prognostic study Limits: Animals Language: Chinese Journal: Chinese Journal of Otorhinolaryngology Head and Neck Surgery Year: 2015 Type: Article

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Full text: Available Index: WPRIM (Western Pacific) Main subject: Potassium Channels / Spiral Ganglion / Rats, Sprague-Dawley / Patch-Clamp Techniques / Cell Biology / Hypoxia / Metabolism / Neurons Type of study: Prognostic study Limits: Animals Language: Chinese Journal: Chinese Journal of Otorhinolaryngology Head and Neck Surgery Year: 2015 Type: Article