Didyk L A, Bogdanov V B, Lysenko V A, Didyk N P, Gorgo Yu P, Dirckx J J J
Institute of Physics of National Academy of Sciences of Ukraine, Pr. Nauki, 46, Kiev, 03028, Ukraine.
Int J Biometeorol. 2007 Jan;51(3):221-31. doi: 10.1007/s00484-006-0051-x. Epub 2006 Sep 21.
This study was designed to clarify whether the pars flaccida (PF) as a flexible part of the tympanic membrane is capable of reacting to pressure oscillations (PO) with amplitudes and frequencies typical for natural atmospheric pressure fluctuations in the far infrasound frequency range (APF). If so, the PF mechanical reactions to APF might be involved in the overall physiologic regulation processes, which make organisms susceptible to APF. The displacements of the PF in response to PO were measured in vitro in ears of gerbils and rabbits by means of laser Doppler vibrometry. The index of the PF reactivity (R(a)) was determined as the ratio of the amplitude of the PF oscillations (PFO) to the amplitude of the PO. All kinds of PO applied caused PFO. The amplitude of the PFO increased when the amplitude of the PO was increased. In gerbils, a decrease in R(a) with the increase in amplitude of the PO was observed. In the range of PO lowest amplitudes (4-20 Pa) R(a) proved to be 1.4 times higher than in the range of highest amplitudes (90-105 Pa). Considering that the natural APF are usually within the range of +/-20 Pa, this fact points to an important contribution of the PF to the pressure dynamics in the middle ear (ME) of gerbils. In rabbit ears, R(a) was lower and recovery from plastic deformation was slower than in gerbils. Our findings are in line with the suggestion that the PF might play an important role in respect of adaptation to natural APF.
本研究旨在阐明鼓膜松弛部（PF）作为鼓膜的一个柔性部分，是否能够对远次声频率范围内自然大气压力波动（APF）所特有的振幅和频率的压力振荡（PO）做出反应。如果是这样，PF对APF的机械反应可能参与了使生物体易受APF影响的整体生理调节过程。通过激光多普勒振动测量法在体外测量了沙鼠和家兔耳朵中PF对PO的位移。将PF反应性指数（R(a)）确定为PF振荡幅度（PFO）与PO幅度的比值。施加的各种PO都会引起PFO。当PO的幅度增加时，PFO的幅度也会增加。在沙鼠中，观察到随着PO幅度的增加R(a)降低。在PO最低幅度范围（4 - 20 Pa）内，R(a)被证明比最高幅度范围（90 - 105 Pa）高出1.4倍。鉴于自然APF通常在±20 Pa范围内，这一事实表明PF对沙鼠中耳（ME）的压力动态有重要贡献。在家兔耳朵中，R(a)较低，且从塑性变形中的恢复比沙鼠慢。我们的研究结果与PF可能在适应自然APF方面发挥重要作用的观点一致。
