title: Excitatory and inhibitory innervation of the mouse orofacial motor nuclei: A stereological study.
abstract: Neurons in the trigeminal (Mo5), facial (Mo7), ambiguus (Amb), and hypoglossal (Mo12) motor nuclei innervate jaw, facial, pharynx/larynx/esophagus, and tongue muscles, respectively. They are essential for movements subserving feeding, exploration of the environment, and social communication. These neurons are largely controlled by sensory afferents and premotor neurons of the reticular formation, where central pattern generator circuits controlling orofacial movements are located. To provide a description of the orofacial nuclei of the adult mouse and to ascertain the influence of excitatory and inhibitory afferents upon them, we used stereology to estimate the number of motoneurons as well as of varicosities immunopositive for glutamate (VGluT1+, VGluT2+) and GABA/glycine (known as VIAAT+ or VGAT+) vesicular transporters in the Mo5, Mo7, Amb, and Mo12. Mo5, Mo7, Amb, and Mo12 contain ∼1,000, ∼3,000, ∼600, and ∼1,700 cells, respectively. VGluT1+, VGluT2+, and VIAAT+ varicosities respectively represent: 28%, 41%, and 31% in Mo5; 2%, 49%, and 49% in Mo7; 12%, 42%, and 46% in Amb; and 4%, 54%, and 42% in Mo12. The Mo5 jaw-closing subdivision shows the highest VGluT1+ innervation. Noticeably, the VGluT2+ and VIAAT+ varicosity density in Mo7 is 5-fold higher than in Mo5 and 10-fold higher than in Amb and Mo12. The high density of terminals in Mo7 likely reflects the convergence and integration of numerous inputs to motoneurons subserving the wide range of complex behaviors to which this nucleus contributes. Also, somatic versus neuropil location of varicosities suggests that most of these afferents are integrated in the dendritic trees of Mo7 neurons.
authors.affiliation: Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.|Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.|Sensory and Motor Systems Group, Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Grafton, 1023, Auckland, New Zealand.
authors.forename: Macarena
authors.initials: M
authors.lastname: Faunes
authors.affiliation: Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.|Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Oñate-Ponce
authors.affiliation: Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.|Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Sara
authors.initials: S
authors.lastname: Fernández-Collemann
authors.affiliation: Laboratorio de Neuroanatomía, Departamento de Anatomía Normal, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.|Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Henny
mesh_terms: D000818:Animals; D002452:Cell Count; D005145:Face / Q000294:innervation*; D065828:Facial Nucleus / Q000166:cytology* / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D007002:Hypoglossal Nerve / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism; D009055:Mouth / Q000294:innervation*; D009433:Neural Inhibition / Q000502:physiology; D009929:Organ Size; D066266:Trigeminal Motor Nucleus / Q000166:cytology* / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D033921:Vesicular Transport Proteins; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005998:Glycine
keywords: AB_1966444; AB_2079751; AB_2254574; AB_2315551; AB_2340396; AB_2340593; VGAT; VGluT1; VGluT2; VIAAT; facial nucleus; hypoglossal nucleus; mouse brainstem; nucleus ambiguus; trigeminal motor nucleus; vesicular transporters