抄録
The ultrastructural changes of subneural apparatus (SA) of neuromuscular junctions in the posterior cricoarytenoid muscle of dog were investigated using a scanning electron microscope. The experiments were carried out under the following three different conditions; 1) section of the recurrent laryngeal nerve, 2) immediate neurorrhaphy after section of the recurrent laryngeal nerve, 3) compression of the recurrent laryngeal nerve. In addition, light microscopic observations of the recurrent laryngeal nerve and evoked electromyographic study were also performed.
1) Nerve section: The primary synaptic cleft became shallower and flattened during six weeks after the section. The slit-like secondary synaptic cleft became round and pit-like form, and its density gradually decreased. These SAs disappeared after twelve weeks.
2) Neurorrhaphy: Molphological restoration of SA was obtained eight weeks after the treatment. The secondary synaptic cleft recovered faster than the primary synaptic cleft. Pararell with morphological recovery, functional restoration of the recurrent laryngeal nerve was proved by evoked electromyography.
3) Nerve compression: From six weeks after the compression, SA recovered morphologically and electromyographically. The course of recovery of SA was similar to that of neurorrhaphy group.
Emphasis was placed on the results that the initiation of morphological restoration of SA was coincided with the functional restoration.
