Vass Z, Brechtelsbauer B, Nuttall A L, Miller J M
Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor 48109-0506, USA.
Acta Otolaryngol. 1995 Nov;115(6):754-8. doi: 10.3109/00016489509139398.
Capsaicin, which causes release of neuropeptides including substance P, has been shown to cause dose-related increases in cochlear blood flow (CBF). Since CBF regulation is altered in animal models with endolymphatic hydrops, this study was designed to examine the effect of hydrops on capsaicin-induced CBF changes. CBF responses to 0.01 and 0.001% capsaicin applied to the round window membrane were measured in normal and 12-week hydropic guinea pigs using laser Doppler flowmetry. With 0.01% capsaicin, CBF increased by only 13 +/- 7.8% in the hydropic ear, compared with 34% +/- 13% in the normal animal (p = 0.027). With 0.001% capsaicin, CBF increased by only 7.5 +/- 4.2% in the hydropic ear, compared with 28 +/- 16% in the normal ear (p < 0.001). These findings demonstrate a reduced responsiveness to capsaicin with endolymphatic hydrops and suggest that hydrops causes an alteration in the peptidergic sensory fibers of the inner ear or in the vascular smooth muscle or both. The results are consistent with previous reports of reduced vascular responsiveness in hydropic guinea pigs and provide further evidence for abnormal CBF regulation in hydrops.
辣椒素可导致包括P物质在内的神经肽释放，已被证明可引起耳蜗血流量（CBF）呈剂量相关增加。由于在伴有内淋巴积水的动物模型中CBF调节发生改变，本研究旨在检测积水对内淋巴积水对辣椒素诱导的CBF变化的影响。使用激光多普勒血流仪测量正常和12周积水豚鼠圆窗膜对0.01%和0.001%辣椒素的CBF反应。使用0.01%辣椒素时，积水耳的CBF仅增加13±7.8%，而正常动物为34%±13%（p = 0.027）。使用0.001%辣椒素时，积水耳的CBF仅增加7.5±4.2%，而正常耳为28±16%（p < 0.001）。这些发现表明内淋巴积水时对辣椒素的反应性降低，提示积水导致内耳肽能感觉纤维或血管平滑肌或两者发生改变。结果与先前关于积水豚鼠血管反应性降低的报道一致，并为积水时CBF调节异常提供了进一步证据。
