TEMPORALLY-SPECIFIC MODIFICATION OF MYELINATED AXON EXCITABILITY INVITRO FOLLOWING A SINGLE ULTRASOUND PULSE
TEMPORALLY-SPECIFIC MODIFICATION OF MYELINATED AXON EXCITABILITY INVITRO FOLLOWING A SINGLE ULTRASOUND PULSE
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DOI：
10.1016/0301-5629(90)90008-z
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发表时间：
1990-01-01
影响因子：
2.9
通讯作者：
WACHTEL, H
中科院分区：
文献类型：
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作者：
MIHRAN, RT;BARNES, FS;WACHTEL, H
在脉冲终止后40-50ms的窗口内，发现单一、短时间、低能量的超声脉冲可引起体外培养的有髓青蛙坐骨神经电兴奋性的明显改变。这些修饰包括增强和抑制相对兴奋性，其序列通常遵循两种不同的时间反应模式之一。超声脉冲聚焦2-7 MHz，持续时间500-微秒，峰值强度100-800W/cm2。总吸收脉冲能量一般小于100mJ/g，相当于神经干局部温升不超过0.025度。C/脉冲，从而排除了作为该效应的基础的整体加热。观察到的效应既不能用阈值下的方波也不能用射频电刺激前刺激，这表明神经干对机械扰动的感受性是独特的形式。我们提出的证据表明，伴随着声脉冲包络的低频辐射压力瞬变是这一现象的活跃参数，并假设它可能通过最近在各种细胞膜中报道的拉伸敏感通道的门控来起作用。这些结果可能表明，神经膜上的拉伸敏感通道可以对通常由电压依赖通道介导的神经电信号进行功能性调制，这一发现可能为高峰值功率、低总能量脉冲超声的新的临床应用提供参考。
Single, short-duration, low-energy pulses of ultrasound were found to elicit distinct modifications of the electrical excitability of myelinated frog sciatic nerve in vitro in a window extending 40-50 ms after pulse termination. These modifications include both enhancement and suppression of relative excitability, the sequence of which generally follows one of two distinct temporal response patterns. The ultrasound pulses were focused, 2-7 MHz, of 500-.mu.s duration, and peak intensities of 100-800 W/cm2. Total absorbed pulse energies were generally less than 100 mJ/g, corresponding to local temperature rises of the nerve trunk of no more than 0.025.degree. C per pulse, thereby precluding bulk heating as a basis of this effect. The observed effects cannot be elicited using either a subthreshold square wave or RF electrical prestimulus, suggesting a unique form of receptivity of the nerve trunk to mechanical perturbation. We present evidence that the low-frequency radiation pressure transient accompanying the envelope of the acoustic pulse is the active parameter in this phenomenon, and postulate that it may act by the gating of stretch-sensitive channels, which have been recently reported in a variety of cell membranes. These results may demonstrate that stretch-sensitive channels in neural membrane can serve to functionally modulate neuro-electric signals normally mediated by voltage-dependent channels, a finding which could suggest new clinical applications of high peak-power, low-total-energy pulsed ultrasound.