• Jonathan S Thacker, Yuyi Xu, Cerise Tang, A Russell Tupling, Staines W Richard WR Department of Kinesiology, Burt Mathews Hall, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, Canada, N2L 3G1., and John G Mielke.
• Division of Medical Sciences, University of Victoria, 3800 Finnerty Road, PO Box 1700 STN CSC, Victoria, British Columbia, V8W 2Y2, Canada; Department of Kinesiology, Burt Mathews Hall, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, Canada, N2L 3G1. Electronic address: jsthacker@uvic.ca.
• Neuroscience. 2019 Aug 1; 412: 160-174.

AbstractA single session of aerobic exercise may offer one means to "prime" motor regions to be more receptive to the acquisition of a motor skill; however, the mechanisms whereby this priming may occur are not clear. One possible explanation may be related to the post-translational modification of plasticity-related receptors and their associated intracellular signaling molecules, given that these proteins are integral to the development of synaptic plasticity. In particular, phosphorylation governs the biophysical properties (e.g., Ca2+ conductance) and the migratory patterns (i.e., trafficking) of plasticity-related receptors by altering the relative density of specific receptor subunits at synapses. We hypothesized that a single session of exercise would alter the subunit phosphorylation of plasticity-related receptors (AMPA receptors, NMDA receptors) and signaling molecules (PKA, CaMKII) in a manner that would serve to prime motor cortex. Young, male Sprague-Dawley rats (n = 24) were assigned to either exercise (Moderate, Exhaustion), or non-exercising (Sedentary) groups. Immediately following a single session of treadmill exercise, whole tissue homogenates were prepared from both the motor cortex and hippocampus. We observed a robust (1.2-2.0× greater than sedentary) increase in tyrosine phosphorylation of AMPA (GluA1,2) and NMDA (GluN2A,B) receptor subunits, and a clear indication that exercise preferentially affects pPKA over pCaMKII. The changes were found, specifically, following moderate, but not maximal, acute aerobic exercise in both motor cortex and hippocampus. Given the requirement for these proteins during the early phases of plasticity induction, the possibility exists that exercise-induced priming may occur by altering the phosphorylation of plasticity-related proteins.Copyright © 2019 IBRO. Published by Elsevier Ltd. All rights reserved.

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