Ambiguus motoneurons innervating laryngeal and esophageal muscles are malpositioned in the Reelin-deficient mutant rat, Shaking Rat Kawasaki.
CONCLUSIONS
The present study confirmed that ambiguus motoneurons innervating intrinsic laryngeal and esophageal muscles are radially malpositioned in the brainstem of the Shaking Rat Kawasaki (SRK), a reelin-deficient mutant rat.


OBJECTIVE
Ambiguus motoneurons innervating the striated muscles of the larynx and esophagus take a long migration from their original birth plate in the floor of the fourth ventricle to their final settlement in the ventral margin of the medulla oblongata. To examine whether the migration of ambiguus nucleus neurons is affected in SRK, we studied localization of ambiguus motoneurons of postnatal day 21 (P21) normal and SRK rats.


METHODS
To label ambiguus motoneurons retrogradely, horseradish peroxidase (HRP) was injected into some laryngeal muscles including cricothyroid, thyroarytenoid and posterior cricoarytenoid muscles, and the cervical and abdominal esophageal muscles of the SRK and normal controls 2 days before sacrifice.


RESULTS
In the P21 normal rat, HRP-positive laryngeal and esophageal motoneurons were found in the nucleus ambiguus, whereas in the P21 SRK, they were scattered from the base of the fourth ventricle to the ventro-lateral margin of the medulla, suggesting that radial migration of ambiguus motoneurons from their birthplace to their final settlement is guided by Reelin protein.
Hirasugi
Kaheita
K
Department of Otorhinolaryngology, Kyoto Prefectual School of Medicine, Kyoto, Japan.
Hisa
Yasuo
Y
Setsu
Tomiyoshi
T
Terashima
Toshio
T
D000818:Animals; D002465:Cell Movement; D004947:Esophagus / Q000294:innervation*; D006735:Horseradish Peroxidase; D007821:Laryngeal Muscles / Q000294:innervation*; D009046:Motor Neurons / Q000473:pathology*; D018482:Muscle, Skeletal / Q000294:innervation*; D010641:Phenotype; D051381:Rats; D011922:Rats, Mutant Strains; D000091042:Reelin Protein
D000091042:Reelin Protein; C000717129:Reln protein, rat; D006735:Horseradish Peroxidase