Neuronal BDNF Signaling Is Necessary for the Effects of Treadmill Exercise on Synaptic Stripping of Axotomized Motoneurons

• Type of Material: Article
• Authors: Joey Krakowiak, Emory University; Caiyue Liu, Second Military Medical University; Chandana Papudesu, Emory University; P.Jillian Ward, Emory University; Jennifer C. Wilhelm, College of Charleston; Arthur W English, Emory University
• Language: English
• Date: 2015-01-01
• Publisher: Hindawi Publishing Corporation
• Publication Version: Final Published Version
• Copyright Statement: © 2015 Joey Krakowiak et al.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1155/2015/392591
• Title of Journal or Parent Work: Neural Plasticity
• ISSN: 2090-5904
• Volume: 2015
• Start Page: 392591
• End Page: 392591
• Grant/Funding Information: This research project was supported in part by the Emory University Integrated Cellular Imaging Microscopy Core.; This work was supported by Grants NS057190 and HD032571 (Arthur W. English) and K12GM000680 (Jennifer C. Wilhelm) from the USPHS.
• Research Categories: Psychology, General; Biology, Cell; Health Sciences, General

Abstract

The withdrawal of synaptic inputs from the somata and proximal dendrites of spinal motoneurons following peripheral nerve injury could contribute to poor functional recovery. Decreased availability of neurotrophins to afferent terminals on axotomized motoneurons has been implicated as one cause of the withdrawal. No reduction in contacts made by synaptic inputs immunoreactive to the vesicular glutamate transporter 1 and glutamic acid decarboxylase 67 is noted on axotomized motoneurons if modest treadmill exercise, which stimulates the production of neurotrophins by spinal motoneurons, is applied after nerve injury. In conditional, neuron-specific brain-derived neurotrophic factor (BDNF) knockout mice, a reduction in synaptic contacts onto motoneurons was noted in intact animals which was similar in magnitude to that observed after nerve transection in wild-type controls. No further reduction in coverage was found if nerves were cut in knockout mice. Two weeks of moderate daily treadmill exercise following nerve injury in these BDNF knockout mice did not affect synaptic inputs onto motoneurons. Treadmill exercise has a profound effect on synaptic inputs to motoneurons after peripheral nerve injury which requires BDNF production by those postsynaptic cells.