Serotonin 1A agonist and cardiopulmonary improvements with whole-body exercise in acute, high-level spinal cord injury: a retrospective analysis

Purpose High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a serotonin agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. Methods We identified 10 patients (< 2 years of injury with SCI from C4 to T3) in our program who had performed 6 months of FES-row training while on Buspirone (29 +/- 17 mg/day) between 2012 and 2018. We also identified well-matched individuals who trained for six months but not on Buspirone (n = 11). A peak incremental FES-rowing exercise test and resting pulmonary function test had been performed before and after training. Results Those on Buspirone demonstrated greater increases in peak oxygen consumption (VO(2)peak: + 0.24 +/- 0.23 vs. + 0.10 +/- 0.13 L/min, p = 0.08) and peak ventilation (VEpeak: + 6.5 +/- 8.1 vs. - 0.7 +/- 6.9 L/min, p < 0.05) compared to control. In addition, changes in VO(2)peak and VEpeak were correlated across all patients (r = 0.63, p < 0.01), but most strongly in those on Buspirone (r = 0.85, p < 0.01). Furthermore, changes in respiratory function correlated with increased peak tidal volume in the Buspirone group (r > 0.66, p < 0.05). Conclusion These results suggest Buspirone improves cardiorespiratory adaptations to FES-exercise training in individuals with acute, high-level SCI. The strong association between increases in ventilatory and aerobic capacities suggests improved respiratory function is a mechanism; however, controlled studies are needed to determine if this preliminary finding is reproducible.

Automated summary

In individuals with acute high-level SCI, the use of Buspirone improves cardiorespiratory adaptations to FES-exercise training, resulting in increased peak oxygen consumption and peak ventilation, which are closely related to improved respiratory function.