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目的 探讨L -型钙通道阻滞药尼福地平对豚鼠耳蜗功能的影响。方法 4 6只健康杂色豚鼠随机分为四组 ,分别全耳蜗灌注含 0 .15、0 .5、3μmol L尼福地平的人工外淋巴液及不含尼福地平的人工外淋巴液 (对照组 ) ,灌流前及灌流 12 0min后圆窗记录耳蜗微音电位 (cochlearmicrophonics ,CM)和耳蜗听神经复合动作电位 (com poundactionpotential,CAP)。比较各组相同时间点的CM振幅和CAP阈值。结果 人工外淋巴液组 (对照组 )灌流后CAP阈值无改变 (P >0 .0 5 ) ,其余组灌流后CAP阈值均升高 (P <0 .0 5 ) ,并随浓度增加阈移增大。灌流后各组CM振幅与 10 0dB声强度时CM振幅比较的相对振幅均下降 ,随浓度增加CM振幅下降更明显。 6只灌流 3μmol L尼福地平的豚鼠 30min后CAP阈值升高 ,CM振幅下降 ,改为单纯人工外淋巴液灌流 90min后 ,CAP阈值及CM振幅有部分恢复。结论 尼福地平对耳蜗功能有抑制作用且有剂量依赖性和部分可逆性 ,间接证明耳蜗毛细胞上存在L-型Ca2 + 通道
Objective To investigate the effect of Nifedipine, a L - type calcium channel blocker, on cochlear function in guinea pigs. Methods4 healthy piglets were randomly divided into four groups: whole-cochlear perfusion with 0.15, 0.05, 3 μmol of nifedipine in artificial perilymph and no-nifedipine in artificial perilymph Group), cochlearmicrophonics (CM) and cochlear com poundaction potential (CAP) were recorded before and after 120 min of perfusion. The CM amplitude and CAP threshold at the same time point were compared between groups. Results After the perfused articular perilymph group (control group), the CAP threshold did not change (P> 0.05), while the other groups were increased after perfusion (P <0.05), and increased with the increase of the threshold Big. After the perfusion, the amplitude of CM in each group decreased compared with the amplitude of 10 0 dB, while the amplitude of CM decreased more with the increase of concentration. The CAP threshold and CM amplitude of 6 guinea pigs that were perfused with 3 μmol of nifedipine were increased 30 min after the infusion of pure perilymph and the amplitude of CM was decreased. Conclusion Nifedipine inhibits cochlear function in a dose-dependent and partially reversible manner, which indirectly proves that there is L-type Ca2 + channel in cochlear hair cells