1 Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA. Electronic address: patsull@uky.edu.
2 Department of Anesthesiology, Center for Shock, Trauma, Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA. Electronic address: gfiskum@som.umaryland.edu.