Article

Trophic factor expression in phrenic motor neurons.

Department of Anesthesiology, Mayo Clinic, 4-184 W. Joseph SMH, 200 First St SW, Rochester, MN 55905, USA.
Respiratory Physiology & Neurobiology (impact factor: 2.24). 08/2008; 164(1-2):252-62. DOI:10.1016/j.resp.2008.07.018 pp.252-62
Source: PubMed

ABSTRACT The function of a motor neuron and the muscle fibers it innervates (i.e., a motor unit) determines neuromotor output. Unlike other skeletal muscles, respiratory muscles (e.g., the diaphragm, DIAm) must function from birth onwards in sustaining ventilation. DIAm motor units are capable of both ventilatory and non-ventilatory behaviors, including expulsive behaviors important for airway clearance. There is significant diversity in motor unit properties across different types of motor units in the DIAm. The mechanisms underlying the development and maintenance of motor unit diversity in respiratory muscles (including the DIAm) are not well understood. Recent studies suggest that trophic factor influences contribute to this diversity. Remarkably little is known about the expression of trophic factors and their receptors in phrenic motor neurons. This review will focus on the contribution of trophic factors to the establishment and maintenance of motor unit diversity in the DIAm, during development and in response to injury or disease.

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Keywords

airway clearance
 
DIAm
 
DIAm motor units
 
diaphragm
 
different types
 
expulsive behaviors
 
motor neuron
 
motor unit
 
motor unit diversity
 
motor unit properties
 
motor units
 
neuromotor output
 
non-ventilatory behaviors
 
phrenic motor neurons
 
Recent studies
 
receptors
 
respiratory muscles
 
skeletal muscles
 
trophic factor influences
 
trophic factors