Laurikainen E, Nuttall A L, Miller J M, Quirk W S, Virolainen E
Kresge Hearing Research Institute, University of Michigan, Ann Arbor.
Acta Otolaryngol. 1992 Sep;112(5):800-9. doi: 10.3109/00016489209137477.
In order to further our basic understanding of the effects of lidocaine hydrochloride in the inner ear, cochlear potentials and blood flow (CBF) were assessed after intravenous (i.v.), anterior inferior cerebellar artery (AICA), and local round window (RW) lidocaine administrations in guinea pigs and rats. Lidocaine RW applications produced a dose dependent decrease in compound action potentials (CAP) and cochlear microphonics (CM). The sensitivity changes were more pronounced at high frequencies. These findings suggest that lidocaine has specific pharmacological action in the inner ear other than simple anesthesia of the auditory nerve. The basal turn endocochlear potentials (EP) were not altered by topical lidocaine, implicating altered organ of Corti function following local application of lidocaine. RW applications of lidocaine had no effect on CBF or systemic blood pressure (BP). I.v. infusions caused substantial reductions in BP. In the case of systemic infusions the percent changes in CBF were equal to and accountable by the BP changes. The microinfusions (50 mg/ml, 100 nl/min) through AICA produced a 30%, long lasting increase in CBF. However, neither systemic lidocaine nor AICA infusions had an effect on CAP or CM. These findings indicate that systemically given lidocaine may not cross the blood-cochlear barrier and that the cochlear electrophysiological effects due to lidocaine when given locally are partly mediated by direct influence on cochlear hair cell function; they also suggest that lidocaine-induced interference with active ion transport in the lateral wall or an influence on CBF are not contributing factors.
为了进一步深入了解盐酸利多卡因在内耳的作用，我们对豚鼠和大鼠分别进行了静脉注射（i.v.）、小脑前下动脉（AICA）注射以及局部圆窗（RW）注射利多卡因后，评估了耳蜗电位和血流量（CBF）。向圆窗应用利多卡因会使复合动作电位（CAP）和耳蜗微音电位（CM）呈剂量依赖性降低。高频时敏感性变化更为明显。这些发现表明，利多卡因在内耳具有特定的药理作用，而非仅仅是对听神经的简单麻醉。局部应用利多卡因不会改变基底转内耳蜗电位（EP），这意味着局部应用利多卡因后柯蒂氏器功能发生了改变。向圆窗应用利多卡因对CBF或全身血压（BP）没有影响。静脉注射会导致血压大幅下降。在全身输注的情况下，CBF的百分比变化与血压变化相等且可由血压变化解释。通过AICA进行微量输注（50 mg/ml，100 nl/min）会使CBF持久增加30%。然而，全身应用利多卡因或通过AICA输注对CAP或CM均无影响。这些发现表明，全身给予利多卡因可能无法穿过血 - 耳蜗屏障，并且局部给予利多卡因时其对耳蜗电生理的影响部分是由对耳蜗毛细胞功能的直接影响介导的；它们还表明，利多卡因对侧壁主动离子转运的干扰或对CBF的影响并非促成因素。
