Synaptic detachment from hypoglossal neurons after different types of nerve injury in the cat

Quantitative electron microscopy was used to examine synaptic numbers and total relative synaptic coverage on hypoglossal neuronal perikarya following transection or crush of the hypoglossal nerve in the cat. In cats subjected to nerve transection there was a statistically significant decrease in total synaptic coverage as well as in number of synaptic contacts/soma profile. After nerve crush there was a statistically significant decrease in total synaptic coverage but not in the number of synaptic contacts. These results indicate that the degree of synaptic detachment on motor neurons in the cat is influenced by the type of nerve injury.