Anterograde axonal transport of [125I]wheat germ agglutinin by motor neurons innervating the rat lateral rectus muscle

Motoneuron loss in the abducens nucleus of wobbler mice

The 'wobbler' mutant mouse can be recognized at about 4 weeks of age by its tremor and atrophy of forelimb muscles. In addition to degeneration of spinal motoneurons, especially in cervical spinal cord, selected bulbar motoneurons have also been reported to degenerate in the mutant. We examined a cranial motor nucleus and found a 31% loss of abducens motoneurons in 4-5-week-old wobbler mice as compared to age-matched control mice.

Localization of axonally transported [125I]wheat germ agglutinin in rat abducens motoneuron axons and terminals after intracisternal injection

Iodinated wheat germ agglutinin (WGA) was taken up and transported by rat abducens motoneurons to nerve terminals in the lateral rectus muscle. Five days after intracisternal injection of lectin, axon terminals wee found to be the most radioactive source, based on the density of labeling. In axons the radioactive label was concentrated in an annular region about 1.26 microns wide beneath the plasma membrane. We hypothesize that the WGA was associated with smooth vesicular and tubular structures in the axoplasm but not limited to organelles immediately beneath the axon plasma membrane. No evidence of intercellular transfer to muscle cells was found.