The effects of EAS of different frequencies on the excitability of various groups in peroneus nerve were studied in rabbits

using standard electro-quantity(a)as the quantitative indices of excitability and consu- lting change of conduction velocity

magnitude and duration course of action potential.The results showed that the excitablity reduction of fibres of various groups is evoked by different frequencies of EAS. Each of fibres of these groups possesses its own critical frequency of EAS

that is

the fibres of group Ⅰ are 200 Hz

the fibres of group Ⅱ are 100 Hz

the fibres of group Ⅲ are 10 Hz and the fibres of group Ⅳ are 5 Hz.Thus

the neurophysiological basis of the selection of the best current intensity and frequency of EAS is provided in electroacupuncture analgesia.It is suggest 1.if a weak current intensity is used to excite the fibres of groups Ⅰ and Ⅱ

the EAS frequency should be less than 100 Hz;2.if a middle current intensity is used to excite the fibres of group Ⅲ

the EAS frequency should be less than 10 Hz;and 3.if a strong current intensity is used to excite the fibres of group Ⅳ

the EAS frequency should be less than 5 Hz.In the above conditions

the safety factor of fibres of various groups would be assured and the excitability of nereve fibres will not be reduced.