Relationship between temperature and stimulation frequency in conduction block of amphibian myelinated axon.

The temperature-frequency relationship in nerve conduction block induced by high-frequency, biphasic electrical current was investigated by computer simulation using an amphibian myelinated axon model based on Frankenhaeuser-Huxley (FH) equations. For an axon of diameter 10 microm, the minimal blocking frequency was changed from 6 to 3 kHz as the temperature was decreased from 37 degrees C to 15 degrees C. The maximal blocking temperature below which the axon could be blocked was increased from 22 degrees C to 37 degrees C as the stimulation frequency was increased from 4 to 8 kHz. The maximal blocking temperature was not influenced by axon diameter. Simulation analysis also revealed that activation of potassium channels might determine the temperature-frequency relationship. This study indicates that temperature might be one of the factors that cause the frequency discrepancy as reported in previous animal studies.