Functional ionotropic glutamate receptors on peripheral axons and myelin. Issue 3 (4th July 2016)

• Record Type: Journal Article
• Authors: Christensen, Pia Crone; Welch, Nicole Cheryl; Brideau, Craig; Stys, Peter K.
• Is Part Of: Muscle & nerve. Volume 54:Issue 3(2016)
• Page Start: 451
• Page End: 459
• Publication Date: 2016-07-04
• Subjects: AMPA -- axon -- myelin -- Ca2+ imaging -- confocal microscopy -- copper NMDA; Neuromuscular diseases -- Periodicals; Muscles -- Periodicals; Nerves -- Periodicals; 616.74
• DOI: 10.1002/mus.25078
• Languages: English
• ISSNs: 0148-639X

Abstract

ABSTRACT: Introduction : Neurotransmitter‐dependent signaling is traditionally restricted to axon terminals. However, receptors are present on myelinating glia, suggesting that chemical transmission may also occur along axons. Methods : Confocal microscopy and Ca 2+ ‐imaging using an axonally expressed FRET‐based reporter was used to measure Ca 2+ changes and morphological alterations in myelin in response to stimulation of glutamate receptors. Results : Activation of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) or N ‐methyl‐D‐aspartate (NMDA) receptors induced a Ca 2+ increase in axon cylinders. However, only the latter caused structural alterations in axons, despite similar Ca 2+ increases. Myelin morphology was significantly altered by NMDA receptor activation, but not by AMPA receptors. Cu 2+ ions influenced the NMDA receptor‐dependent response, suggesting that this metal modulates axonal receptors. Glutamate increased ribosomal signal in Schwann cell cytoplasm. Conclusions : Axon cylinders and myelin of peripheral nervous system axons respond to glutamate, with a consequence being an increase in Schwann cell ribosomes. This may have implications for nerve pathology and regeneration. Muscle Nerve 54 : 451–459, 2016