EFFECTS OF FOCUSED ULTRASONIC RADIATION ON PERIPHERAL NERVE, WITH OBSERVATIONS ON LOCAL HEATING
EFFECTS OF FOCUSED ULTRASONIC RADIATION ON PERIPHERAL NERVE, WITH OBSERVATIONS ON LOCAL HEATING
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DOI：
10.1016/0014-4886(63)90008-6
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发表时间：
1963-01-01
影响因子：
5.3
通讯作者：
LELE, P
中科院分区：
文献类型：
--
作者：
LELE, P
在猫，猴子和人的450多个外周神经中研究了用2.7 mc，900 kc和600 kc在神经传导的频率下进行辐射的影响。使用worm的巨型纤维来确认获得的结果。充分强度的辐照引起了随剂量进行的变化：第一阶段，增强的变化，其特征在于传导速度的增加和动作电位的高度，随后是可逆和差分抑郁阶段的阶段不可逆转的抑郁症。在较大的纤维中，较小的纤维的传导更早地受到影响，但是不可能阻止较小的纤维，除非很短，但也不会阻止较大的纤维。产生给定作用所需的超声剂量水平取决于辐照区域的神经周围的介质。剂量水平与单个超声脉冲在培养基中产生的热量成反比。提供的和其他证据表明，观察到的效应是热中介导的。超声辐射对神经传导的所有生理影响都可以通过将渐变量的热量施加到小段神经中来复制。在显微镜检查中，通过超声辐射阻塞的神经与被热量阻止的神经无法区分。通过经皮辐射会损害上覆的皮肤和潜在的肌肉所需的超声剂量以阻断皮下神经的传导。
The effects of irradiation with a single beam of focused ultrasound at the frequencies of 2.7 Mc, 900 kc, and 600 kc on nerve conduction were studied in over 450 peripheral nerves of the cat, monkey and man. Giant fibers of the earthworm were used to confirm the results obtained. Irradiation at an adequate intensity caused changes which were progressive with dosage: The first phase, that of enhancement, characterized by increase in the velocity of conduction and in the height of the action potential, was followed by a phase of reversible and differential depression and then that of irreversible depression. Conduction in smaller fibers was affected earlier than that in larger fibers but it was not possible to block the smaller fibers, except for very brief periods, without also blocking the larger fibers. The ultrasonic dosage levels required to produce a given effect were dependent on the medium surrounding the nerve in the region of irradiation. The dosage levels were inversely related to the amount of heat generated in the medium by a single pulse of ultrasound. This and other evidence presented indicates that the observed effects are mediated thermally. All physiological effects of ultrasonic radiation on nerve conduction can be duplicated by application of graded amounts of heat to small segments of nerves. On microscopical examination nerves blocked by ultrasonic irradiation are indistinguishable from those blocked by application of heat. The dosage of ultrasound required to block conduction in subcutaneous nerves by transcutaneous irradiation damages both the overlying skin as well as the underlying muscle.