TY - JOUR
T1 - Secretagogin Immunoreactivity Reveals Lugaro Cells in the Pigeon Cerebellum
AU - Craciun, Iulia
AU - Gutierrez-Ibanez, Cristian
AU - Chan, Alyssa S.M.
AU - Luksch, Harald
AU - Wylie, Douglas R.
N1 - Publisher Copyright:
© 2019, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2019/6/15
Y1 - 2019/6/15
N2 - Lugaro cells are inhibitory interneurons found in the upper granular layer of the cerebellar cortex, just below or within the Purkinje cell layer. They are characterized by (1) a fusiform soma oriented in the parasagittal plane, (2) two pairs of dendrites emanating from opposite ends of the soma, (3) innervation from Purkinje cell collaterals, and (4) an axon that projects into the molecular layer akin to granular cell parallel fibers. Lugaro cells have been described in mammals, but not in other vertebrate classes, save one report in teleost fish. Here, we propose the existence of Lugaro cells in the avian cerebellum based on the morphological characteristics and connectivity described above. Immunohistochemical staining against the calcium binding protein secretagogin (SCGN) revealed Lugaro-like cells in the pigeon cerebellum. Some SCGN-labeled cells exhibit fusiform somata and dendrites parallel to the Purkinje cell layer in the parasagittal plane, as well as long axons that project into the molecular layer and travel alongside parallel fibers in the coronal plane. While mammalian Lugaro cells are known to express calretinin, the SCGN-labeled cells in the pigeon do not. SCGN-labeled cells also express glutamic acid decarboxylase, confirming their inhibitory function. Calbindin labeling revealed Purkinje cell terminals surrounding the SCGN-expressing cells. Our results suggest that Lugaro cells are more widespread among vertebrates than previously thought and may be a characteristic of the cerebellum of all vertebrates.
AB - Lugaro cells are inhibitory interneurons found in the upper granular layer of the cerebellar cortex, just below or within the Purkinje cell layer. They are characterized by (1) a fusiform soma oriented in the parasagittal plane, (2) two pairs of dendrites emanating from opposite ends of the soma, (3) innervation from Purkinje cell collaterals, and (4) an axon that projects into the molecular layer akin to granular cell parallel fibers. Lugaro cells have been described in mammals, but not in other vertebrate classes, save one report in teleost fish. Here, we propose the existence of Lugaro cells in the avian cerebellum based on the morphological characteristics and connectivity described above. Immunohistochemical staining against the calcium binding protein secretagogin (SCGN) revealed Lugaro-like cells in the pigeon cerebellum. Some SCGN-labeled cells exhibit fusiform somata and dendrites parallel to the Purkinje cell layer in the parasagittal plane, as well as long axons that project into the molecular layer and travel alongside parallel fibers in the coronal plane. While mammalian Lugaro cells are known to express calretinin, the SCGN-labeled cells in the pigeon do not. SCGN-labeled cells also express glutamic acid decarboxylase, confirming their inhibitory function. Calbindin labeling revealed Purkinje cell terminals surrounding the SCGN-expressing cells. Our results suggest that Lugaro cells are more widespread among vertebrates than previously thought and may be a characteristic of the cerebellum of all vertebrates.
KW - Birds
KW - Cerebellar circuits
KW - Cerebellum
KW - Evolution
KW - Immunohistochemistry
KW - Lugaro cells
KW - Secretagogin
UR - http://www.scopus.com/inward/record.url?scp=85066163682&partnerID=8YFLogxK
U2 - 10.1007/s12311-019-01023-7
DO - 10.1007/s12311-019-01023-7
M3 - Article
C2 - 30904983
AN - SCOPUS:85066163682
SN - 1473-4222
VL - 18
SP - 544
EP - 555
JO - Cerebellum
JF - Cerebellum
IS - 3
ER -