Effects of low intensity ultrasound on the conduction property of neural tissues

The effects of low intensity ultrasound on the nerve tissues were explored in this study. A 5 MHz transducer was employed to generate different energy, including 200, 500, and 700 mW, and duty cycles, from 25 to 100% in a 2 KHz pulse repetition frequency, of ultrasounds were administrated to the excised sciatic nerve suspended in the Ringer's solution in conjunction with electrical stimulations. The conduction properties of an excised nerve were assessed by the magnitude of compound action potential (CAP) and conduction velocity (CV). Results showed that both CAP and CV of the sciatic nerve tended to increase or decrease associated with ultrasonic stimulations of all energy at a duty cycle of 100% or without ultrasonic stimulation, respectively. The stimulation using a 500 mW ultrasound was found to moreover result greater changes of CAP and CV (41.3% and 3.8%, respectively) than those by other energies. Consistent results were also found from a series of studies that applied a 500 mW ultrasound of different duty cycles ranged from 25% to 75% to stimulate the sciatic nerve for 5 minutes. This study concluded that the low intensity ultrasound is useful to enhance the CV and the CAP amplitude.