TY - JOUR
T1 - Development of the facial and hypoglossal motor nuclei in the neonatal Brazilian opossum brain
AU - Swanson, Jack J.
AU - Kuehl-Kovarik, M. Cathleen
AU - Elmquist, Joel K.
AU - Sakaguchi, Donald S.
AU - Jacobson, Carol D.
N1 - Funding Information:
The authors thank Tracey M. Pepper for her help with photomicrograph production and Dr. Javed Iqbal for his expertise concerning the injection of Brazilian opossum pups. We also thank the Iowa State University Image Analysis Facility for providing a Zeiss Axiophot microscope. This work was supported by the Whitehall Foundation and the National Science Foundation. This manuscript, designated by Iowa State University as J-18110 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA, project number 3205, was supported by the Hatch Act and State of Iowa Funds.
PY - 1999/2/5
Y1 - 1999/2/5
N2 - The development of the facial and hypoglossal motor nuclei were examined in the neonatal Brazilian opossum (Monodelphis domestica), a marsupial in which postnatal central nervous system development has been well characterized. In this study, we utilized postnatal injection of the retrograde tracer cholera toxin subunit B (CtB) to characterize the formation of the facial and hypoglossal motor nuclei in the developing neonatal opossum brainstem. Injections of CtB were made into the cheek/lip region or tongue of opossum pups to retrogradely label the facial or hypoglossal motor nuclei, respectively. Following a 2 h survival time, facial motoneurons in newborn opossum pups (1 PN) exhibited CtB labeling, with their cell bodies localized near the developing cranial abducens nucleus. At 3 and 5 PN, following a 48 h survival time, CtB-labeled facial moroneurons were observed in and migrating to the region of the adult facial motor nucleus in the rostral medulla. Between 7 and 10 PN, almost all facial moroneurons had migrated to their destination within the facial motor nucleus. Hypoglossal motoneurons also exhibited CtB labeling from 1 PN; however, their cell bodies were localized within the hypoglossal motor nucleus at the earliest age examined. Double label studies, to examine guidance of facial motoneurons during migration, demonstrated that CtB-labeled facial motoneurons are in close proximity to vimentin-like immunostained radial glial fibers during migration. These results suggest: (1) migration of facial moroneurons to the facial motor nucleus is a postnatal event, (2) efferent projections from facial and hypoglossal moroneurons project into the peripheral region of their target muscles from the day of birth, and (3) facial motoneurons migrate to their destination in the brainstem thereafter, in close association with radial glial fibers.
AB - The development of the facial and hypoglossal motor nuclei were examined in the neonatal Brazilian opossum (Monodelphis domestica), a marsupial in which postnatal central nervous system development has been well characterized. In this study, we utilized postnatal injection of the retrograde tracer cholera toxin subunit B (CtB) to characterize the formation of the facial and hypoglossal motor nuclei in the developing neonatal opossum brainstem. Injections of CtB were made into the cheek/lip region or tongue of opossum pups to retrogradely label the facial or hypoglossal motor nuclei, respectively. Following a 2 h survival time, facial motoneurons in newborn opossum pups (1 PN) exhibited CtB labeling, with their cell bodies localized near the developing cranial abducens nucleus. At 3 and 5 PN, following a 48 h survival time, CtB-labeled facial moroneurons were observed in and migrating to the region of the adult facial motor nucleus in the rostral medulla. Between 7 and 10 PN, almost all facial moroneurons had migrated to their destination within the facial motor nucleus. Hypoglossal motoneurons also exhibited CtB labeling from 1 PN; however, their cell bodies were localized within the hypoglossal motor nucleus at the earliest age examined. Double label studies, to examine guidance of facial motoneurons during migration, demonstrated that CtB-labeled facial motoneurons are in close proximity to vimentin-like immunostained radial glial fibers during migration. These results suggest: (1) migration of facial moroneurons to the facial motor nucleus is a postnatal event, (2) efferent projections from facial and hypoglossal moroneurons project into the peripheral region of their target muscles from the day of birth, and (3) facial motoneurons migrate to their destination in the brainstem thereafter, in close association with radial glial fibers.
KW - Brainstem
KW - Cholera toxin subunit B
KW - Migration
KW - Monodelphis
KW - Motoneuron
KW - Motor neuron
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U2 - 10.1016/S0165-3806(98)00160-6
DO - 10.1016/S0165-3806(98)00160-6
M3 - Article
C2 - 9878718
AN - SCOPUS:0033524809
SN - 0165-3806
VL - 112
SP - 159
EP - 172
JO - Developmental Brain Research
JF - Developmental Brain Research
IS - 2
ER -