Spontaneous electrical activity of rabbit trigger spot after transection of spinal cord and peripheral nerve

Objectives: To assess the changes in the prevalence and the morphology of spontaneous electrical activity [SEA] after spinal cord transection and subsequent nerve transection in an animal model of myofascial trigger point [MTrP] in order to further understand the mechanism of MTrP. Spontaneous electrical activity can be recorded from a minute locus in a human MTrP region, and also from that in the myofascial trigger spot [similar to human MTrP] of rabbit skeletal muscle. Methods: Four adult albino rabbits were studied for the prevalence and amplitude changes of SEA in the biceps femoris muscle before and after spinal cord transection at the level of T4 or T5, and also after subsequent transection of the sciatic nerve. Results: There was no significant change in the prevalence and amplitude of SEA up to 60 minutes after spinal cord transection and 30 minutes after subsequent nerve transection. Conclusions: The occurrence of SEA is not mediated through the spinal or supraspinal circuits. The origin of SEA appears to be a local motor endplate phenomenon.