Activities of respiratory laryngeal motoneurones were recorded intracellularly in the nucleus ambiguus of the cat. Some of them were intracellularly injected with peroxidase for morphological reconstruction. Stimulation of the superior laryngeal nerve (SLN) evoked excitatory responses in both somata and axons of expiratory laryngeal motoneurones. In inspiratory laryngeal motoneurones, the responses induced by the SLN depended on the site of recording: inhibition and decrease of excitatory input in somata, excitation in axons. We conclude that excitatory synaptic effects of SLN stimulation acts mainly on, or close to, the initial segment of inspiratory motoneurones, while inhibition reaches the somato-dendritic region.
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http://dx.doi.org/10.1016/0304-3940(84)90414-2 | DOI Listing |
J Physiol
January 2025
Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
Motor neurons (MNs) within the nucleus ambiguus innervate the skeletal muscles of the larynx, pharynx and oesophagus, which are essential for swallow. Disordered swallow (dysphagia) is a serious problem in elderly humans, increasing the risk of aspiration, a key contributor to mortality. Despite this importance, very little is known about the pathophysiology of ageing dysphagia and the relative importance of frank muscle weakness compared to timing/activation abnormalities.
View Article and Find Full Text PDFPflugers Arch
January 2025
Division of Neurophysiology, Department of Physiology, Hyogo Medical University, Hyogo, 663 8501, Japan.
The nucleus tractus solitarius (NTS) contains neurons that relay sensory swallowing commands information from the oropharyngeal cavity and swallowing premotor neurons of the dorsal swallowing group (DSG). However, the spatio-temporal dynamics of the interplay between the sensory relay and the DSG is not well understood. Here, we employed fluorescence imaging after microinjection of the calcium indicator into the NTS in an arterially perfused brainstem preparation of rat (n = 8) to investigate neuronal population activity in the NTS in response to superior laryngeal nerve (SLN) stimulation.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Institute of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätstraße 19, 91054 Erlangen, Germany.
Human vocalization is a complex process that is still only partially understood. Previous studies have suggested the possibility of a localized neuromuscular network of the larynx. Here we investigate this structure in human dissection specimens using multiple immunofluorescence and transmission electron microscopy (TEM).
View Article and Find Full Text PDFIndian J Otolaryngol Head Neck Surg
December 2024
Department of ENT-HNS, Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University Teaching Hospital, Kathmandu, Nepal.
J Comp Neurol
November 2024
Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.
The control of the respiratory rhythm and airway motor activity is essential for life. Accumulating evidence indicates that the postinspiratory complex (PiCo) is crucial for generating behaviors that occur during the postinspiratory phase, including expiratory laryngeal activity and swallowing. Located in the ventromedial medulla, PiCo is defined by neurons co-expressing two neurotransmitter markers (ChAT and Vglut2/Slc17a6).
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