title: Coordination of NMDA-induced rhythmic activity in the trigeminal and hypoglossal nerves of neonatal mice in vitro.
abstract: Suckling is a rhythmic jaw movement that is symmetrical on the left and right side and is highly coordinated with tongue movement. Thus, we investigated the neuronal mechanisms of the left/right and jaw/tongue coordinations during N-methyl-d-aspartate (NMDA)-induced fictive suckling using isolated brainstem-spinal cord preparations obtained from neonatal mice. We observed synchronous low-frequency rhythmic activity in the left/right trigeminal motor nerves, which differed from respiration, and high-frequency rhythmic trigeminal activity, which was side-independent. The low-frequency rhythmic trigeminal activity was also synchronized with the hypoglossal nerve activity. After a complete midline separation of the preparation or a partial midline transection of the brainstem from the anterior inferior cerebellar artery to the junction of the vertebral artery, the low-frequency rhythmic trigeminal activity disappeared, whereas the high-frequency rhythmic trigeminal activity and low-frequency rhythmic hypoglossal activity still remained. These results suggest that the neuronal network that generates low-frequency rhythmic activity likely contributes to the synchronized activity of the left/right jaw muscles and to the jaw/tongue muscles, where it sends its command to the trigeminal motoneurons mainly via the commissural pathway that crosses the transected midline region. Such a neuronal network may underlie the coordinated movements of the jaw and tongue during suckling.
authors.affiliation: Department of Oral Rehabilitation, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ihara
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Nakayama
authors.forename: Shiro
authors.initials: S
authors.lastname: Nakamura
authors.forename: Ayako
authors.initials: A
authors.lastname: Mochizuki
authors.forename: Koji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Tomio
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D007002:Hypoglossal Nerve / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D013391:Sucking Behavior / Q000187:drug effects / Q000502:physiology*; D014276:Trigeminal Nerve / Q000187:drug effects / Q000502:physiology
chemical_list: D016202:N-Methylaspartate