Fig. 1.
Central illustration and timeline of experimental protocol. (A) Proposed pathway for ischemia-induced sympathoexcitation, and 1 to 3 are proposed sites for spinal cord stimulation γ -aminobutyric acid (GABA)–mediated inhibition of cardiac sympathoexcitation. (B) Experimental protocol and treatment groups for spinal cord stimulation mechanistic investigation Yorkshire pigs were randomized to six groups: control, ischemia–reperfusion, ischemia–reperfusion plus spinal cord stimulation, ischemia–reperfusion plus spinal cord stimulation plus γ-aminobutyric acid type A (GABAA) antagonist bicuculline, ischemia–reperfusion plus spinal cord stimulation plus γ-aminobutyric acid type B (GABAB) antagonist CGP55845, and ischemia–reperfusion plus GABA transaminase inhibitor groups. Spinal cord stimulation was initiated 30 min before ischemia. The intrathecal GABA antagonists were each applied 5 min before the start of spinal cord stimulation and reapplied every 60 min after that. Intrathecal GABA transaminase inhibitor was applied after baseline control measures and reapplied every 60 min.