Measurement of nerve conduction velocity

The evaluation of neuropathy, via nerve conduction velocity, was performed at 10 weeks of age in female SDT fatty rats. Nerve conduction velocity was measured in accordance with previously described methods (15). The sciatic nerve was stimulated at the sciatic notch and the Achilles tendon using adequate intensity under 37.5 mg/kg of sodium pentobarbital (Kanto chemical, Tokyo, Japan) and 3 mg/kg of diazepam anesthesia. The action potential in the muscle was recorded via PowerLab through a needle electrode (Figure 1A). Motor nerve conduction velocity (MNCV) was calculated from the delta latency between M-wave peaks divided by the distance of the nerve length measured. Sensory nerve conduction velocity (SNCV) was also calculated from H-wave peaks (Figure 1B).

The formulas used to calculate MNCV and SNCV were as follows.

MNCV (m/sec) = distance between the sciatic notch and Achilles tendon (mm)/peak latency of an M-wave in the sciatic notch – peak latency of an M-wave in the Achilles tendon (msec).

SNCV (m/sec) = distance between the sciatic notch and Achilles tendon (mm)/peak latency of an H-wave in the Achilles tendon – peak latency of an H-wave in the sciatic notch (msec).