A simple and effective auxiliary device for detection of physiologic function on isolated sciatic nerve and gastrocnemius in toads

AIM: To design a simple and effective auxiliary device for detection of the compound action potential (CAP) and the force on the isolated sciatic nerve and gastrocnemius in toads, and to investigate its practicability. METHODS: A simple "L" shape device (L tube), which was composed of a nerve chamber and an organ bath, was made for fixing the isolated sciatic nerve and gastrocnemius. After fixing, the sciatic CAP and the gastrocnemius force were detected by BL-420S data acquisition and analysis system. The specimens were radomly divided into control group, and the lidocaine nerve and muscle groups. The sciatic nerve or gastrocnemius of each lidocaine group was firstly treated with the corresponding concentration of lidocaine, and then washed out with Ringer's solution, and its reversible anesthetic action on nerve conduction and muscle force was analyzed to verify the practicability of the L tube device. RESULTS: The CAP and the force of the sciatic-gastrocnemius specimens were detected concurrently by fixing the specimens in the L tube, and the liquid in the nerve chamber and organ bath was changed easily. Compared with the control, lidocaine at 0.05 and 0.2 g/L significantly increased the sciatic threshold stimulus voltage and maximal stimulus voltage (P<0.05), prolonged the absolute refractory period (P<0.01), and slowed down the conduction velocity (P<0.01). Lidocaine at 1 g/L completely blocked the sciatic conduction. The rest tension of the gastrocnemius was increased, and the maximal twitch force was decreased significantly by 1 g/L lidocaine (P<0.01), but the threshold and maximal stimulus voltage did not show statistic difference. The parameters of the sicatic nerve and gastrocnemius completely or partially recovered to the control level after washing out.CONCLUSION: As an auxiliary device, L tube makes the detection of CAP and force on the isolated sciatic nerve and gastrocnemius in toads more conveniently.