• Yasin B Seven, Latoya L Allen, Marissa C Ciesla, Kristin N Smith, Amanda Zwick, Alec K Simon, Ashley E Holland, Juliet V Santiago, Kelsey Stefan, Ashley Ross, Elisa J Gonzalez-Rothi, and Gordon S Mitchell.
• Breathing Research and Therapeutics Center, Department of Physical Therapy and, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA.
• Neuroscience. 2022 Dec 1; 506: 385038-50.

AbstractCervical spinal cord injury (cSCI) impairs neural drive to the respiratory muscles, causing life- threatening complications such as respiratory insufficiency and diminished airway protection. Repetitive "low dose" acute intermittent hypoxia (AIH) is a promising strategy to restore motor function in people with chronic SCI. Conversely, "high dose" chronic intermittent hypoxia (CIH; ∼8 h/night), such as experienced during sleep apnea, causes pathology. Sleep apnea, spinal ischemia, hypoxia and neuroinflammation associated with cSCI increase extracellular adenosine concentrations and activate spinal adenosine receptors which in turn constrains the functional benefits of therapeutic AIH. Adenosine 1 and 2A receptors (A1, A2A) compete to determine net cAMP signaling and likely the tAIH efficacy with chronic cSCI. Since cSCI and intermittent hypoxia may regulate adenosine receptor expression in phrenic motor neurons, we tested the hypotheses that: 1) daily AIH (28 days) downregulates A2A and upregulates A1 receptor expression; 2) CIH (28 days) upregulates A2A and downregulates A1 receptor expression; and 3) cSCI alters the impact of CIH on adenosine receptor expression. Daily AIH had no effect on either adenosine receptor in intact or injured rats. However, CIH exerted complex effects depending on injury status. Whereas CIH increased A1 receptor expression in intact (not injured) rats, it increased A2A receptor expression in spinally injured (not intact) rats. The differential impact of CIH reinforces the concept that the injured spinal cord behaves in distinct ways from intact spinal cords, and that these differences should be considered in the design of experiments and/or new treatments for chronic cSCI.Copyright © 2022 IBRO. Published by Elsevier Ltd. All rights reserved.

13 keywords...

hide…