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Development of hypoglossal motoneurons
A J Berger1, D A Bayliss, F Viana
1Department of Physiology and Biophysics, School of Medicine, University of Washington, Seattle 98195-7290, USA. Berger@u.washington.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 1, 1996
Summary
Hypoglossal motoneurons (HMs) undergo significant postnatal development, altering their structure and electrical properties. These changes impact upper airway control by modifying neuronal excitability and ion channel function.
Area of Science:
- Neuroscience
- Developmental Biology
Background:
- Hypoglossal motoneurons (HMs) innervate tongue muscles, crucial for upper airway control.
- Postnatal development significantly alters the properties of HMs.
Purpose of the Study:
- To investigate the developmental changes in rat hypoglossal motoneuron morphology and electrical properties during the early postnatal period.
- To understand how these changes affect neuronal excitability and function.
Main Methods:
- In vitro electrophysiological recordings from rat HMs.
- Morphological analysis of dendritic complexity.
- Ion channel density measurements.
Main Results:
- Dendritic complexity of HMs decreases within the first 2 weeks postnatal.
- Motoneuronal input resistance falls progressively due to decreased membrane resistivity, increasing rheobase and reducing excitability.
- Ion channel densities change, with a larger hyperpolarization-activated cationic current in adults and a declining T-type Ca2+ channel density in neonates.
Conclusions:
- Postnatal development involves substantial morphological and electrophysiological remodeling of HMs.
- These developmental changes are critical for the maturation of upper airway motor control circuits.