Therapeutic potential of spinal cord stimulation for gastrointestinal motility disorders: A preliminary rodent study

Background: Spinal cord electrical stimulation (SCS) has been applied for the management of chronic pain. Most of studies have revealed a decrease in sympathetic activity with SCS. The aim of this study was to investigate the effects and mechanisms of SCS on gastrointestinal (GI) motility in healthy and diabetic rats. Methods: Male rats chronically implanted with a unipolar electrode at T9/T10 were studied. The study included four experiments to assess the effects of SCS on (1) gastric tone; (2) gastric emptying of liquids and intestinal transit; (3) gastric emptying of solids; and (4) sympathovagal balance in healthy rats and/or in Streptozotocin (STZ)-induced diabetic rat. Key Results: (1) Spinal cord stimulation intensity dependently increased gastric tone in healthy rats. The gastric volume was 0.97 ± 0.15 mL at baseline, and decreased to 0.92 ± 0.16 mL with SCS of the 30% motor threshold (MT; p = 0.13 vs baseline), 0.86 ± 0.14 mL with 60% MT (p = 0.045 vs baseline), and 0.46 ± 0.19 mL with 90% MT (p = 0.0050 vs baseline). (2) Spinal cord stimulation increased gastric emptying of liquids by about 17% and accelerated small intestinal transit by about 20% in healthy rats (p < 0.001). (3) Spinal cord stimulation accelerated gastric emptying of solids by about 24% in healthy rats and by about 78% in diabetic rats. (4) Spinal cord stimulation decreased sympathetic activity (1.13 ± 0.18 vs 0.68 ± 0.09, p < 0.04) and sympathovagal balance (0.51 ± 0.036 vs 0.40 ± 0.029, p = 0.028). Conclusions & Inferences: Spinal cord stimulation accelerates gastric emptying of liquids and solids, and intestinal transit, probably by inhibiting the sympathetic activity. Spinal cord stimulation may have a therapeutic potential for treating GI motility disorders.