Nerve injury induces gap junctional coupling among axotomized adult motor neurons

• Type of Material: Article
• Authors: Qiang Chang, University of Pennsylvania; Alberto Pereda, Medical College of Pennsylvania; Martin Pinter, Emory University; Rita J. Balice-Gordon, University of Pennsylvania
• Language: English
• Date: 2000-01-15
• Publisher: Society for Neuroscience
• Publication Version: Final Published Version
• Copyright Statement: © 2000 Society for Neuroscience
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1523/JNEUROSCI.20-02-00674.2000
• Title of Journal or Parent Work: Journal of Neuroscience Nursing
• Volume: 20
• Issue: 2
• Start Page: 674
• End Page: 684
• Grant/Funding Information: This work was supported by National Institutes of Health Grant NS34373, Spinal Cord Research Foundation of Paralyzed Veterans of America Grant 1472, and a McKnight Neuroscience Scholar award to R.B.-G.
• Keywords: SCIATIC-NERVE; motor neuron; ELECTRICAL-PROPERTIES; Neurosciences & Neurology; UNIT TYPE; PERIPHERAL AXOTOMY; injury; CAT; MOLECULAR-CLONING; DENERVATED RAT MUSCLE; Life Sciences & Biomedicine; axotomy; connexin; skeletal muscle; Neurosciences; SPINAL-CORD; CONNEXIN EXPRESSION; FACIAL NUCLEUS; nerve; gap junction; Science & Technology
• Research Categories: Biology, Animal Physiology; Biology, Neuroscience

Abstract

Neonatal spinal motor neurons are electrically and dye-coupled by gap junctions, but coupling is transient and disappears rapidly after birth. Here we report that adult motor neurons become recoupled by gap junctions after peripheral nerve injury. One and 4-6 weeks after nerve cut, clusters of dye- coupled motor neurons were observed among axotomized, but not control, lumbar spinal motor neurons in adult cats. Electrical coupling was not apparent, probably because of the electrotonic distance between dendrodendritic gap junctions and the somatic recording location. Analyses of gap junction protein expression in cat and rat showed that the repertoire of connexins expressed by normal adult motor neurons, Cx36, Cx37, Cx40, Cx43, and Cx45, was unchanged after axotomy. Our results suggest that the reestablishment of gap junctional coupling among axotomized adult motor neurons may occur by modulation of existing gap junction proteins that are constitutively expressed by motor neurons. After injury, interneuronal gap junctional coupling may mediate signaling that maintains the viability of axotomized motor neurons until synaptic connections are reestablished within their targets.