Regulation of dopamine D2 receptors in the guinea pig cochlea
Regulation of dopamine D2 receptors in the guinea pig cochlea
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豚鼠耳蜗多巴胺 D2 受体的调节
DOI：
10.3109/00016489.2014.899712
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发表时间：
2014-07-01
影响因子：
1.4
通讯作者：
Li, Xingqi
中科院分区：
文献类型：
--
作者：
Wang, Lin;Li, Jingjing;Li, Xingqi
结论：我们的研究表明D2受体的调节可能是频率特异性的。D2受体拮抗剂灌流后耳蜗微音学(CM)和失真产物耳声发射(DPOAE)波幅降低，提示该受体在耳蜗毛细胞激活中起调节作用。目的：多巴胺能终末受多巴胺D2受体的负反馈作用。在本研究中，我们研究了多巴胺D2受体的调节是否具有频率特异性，并评估了豚鼠耳蜗肌中CM的变化。方法：30只雄性豚鼠随机分为3组，分别用人工外淋巴液(AP)、含0.1%乙醇的AP或D2拮抗剂(L741626)灌流2 h，每组分别在灌流前和灌流后2 h测定1、2、4、8、16和24 kHz纯音诱发的复合动作电位(CAP)、4 kHz纯音爆发诱发的CM和DPOAEs。结果：D2拮抗剂灌流使CAP阈值在高频(4、8、16、24 kHz，p<；0.05)较其他两组升高，而在低频(1、2 kHz，p>；0.05)则无明显升高。D2拮抗剂灌流2 h后，DPOAEs和CM波幅显著降低。以刺激水平为输入，以CM相对幅度为输出绘制的CM输入输出(I/O)功能曲线，在灌流后2 h，3组均表现出明显的非线性。
Abstract Conclusion: Our study demonstrates that the regulation of D2 receptors may be frequency specific. The reduction in cochlear microphonics (CM) and distortion product otoacoustic emission (DPOAE) amplitudes after perfusion with a D2 antagonist suggests that this receptor plays a role in the regulation of cochlear hair cell activation. Objectives: Dopaminergic terminals are subject to negative feedback from dopamine D2 receptors. In the present study we investigated whether the regulation of dopamine D2 receptor is frequency specific and evaluated changes in CM in guinea pig cochlea. Methods: A total of 30 male guinea pigs were randomly assigned to 3 groups and perfused with artificial perilymph (AP), AP containing ethanol (0.1%), or a D2 antagonist (L741626) for 2 h. In each group, compound action potentials (CAPs) evoked by a 1, 2, 4, 8, 16 or 24 kHz tone pip, CM evoked by 4 kHz tone bursts, and DPOAEs were measured before and 2 h after perilymphatic perfusion. Results: Perfusion with the D2 antagonist resulted in increased CAP thresholds compared with the other two groups at high frequencies (4, 8, 16, 24 kHz, p < 0.05); however, no significant increase was observed at low frequencies (1, 2 kHz, p > 0.05). There was a significant reduction in DPOAEs and CM amplitudes after the 2 h perfusion with the D2 antagonist. A CM input/output (I/O) function curve plotted with the stimulating level as input and the CM relative amplitude as output indicated obvious nonlinearity after the 2 h perfusion in all three groups.