Respiratory resetting elicited by single pulse spinal stimulation

Publication date: Available online 14 November 2019Source: Respiratory Physiology & NeurobiologyAuthor(s): Michael D Sunshine, Comron N Ganji, David D Fuller, Chet T MoritzAbstractIntraspinal microstimulation (ISMS) can effectively activate spinal motor circuits, but the impact on the endogenous respiratory pattern has not been systematically evaluated. Here we delivered ISMS in spontaneously breathing adult rats while simultaneously recording diaphragm and external intercostal electromyography activity. ISMS pulses were delivered from C2–T1 along two rostrocaudal tracts located 0.5 or 1 mm lateral to midline. A tungsten electrode was incrementally advanced from the dorsal spinal surface and 300µs biphasic pulses (10-90 µA) were delivered at depth increments of 600 µm. Dorsal ISMS often produced fractionated inspiratory bursting or caused early termination of the inspiratory effort. Conversely, ventral stimulation had no discernable impact on respiratory resetting. We conclude that ISMS targeting the ventral spinal cord is unlikely to directly alter the respiratory rhythm. Dorsal ISMS, however, may terminate the inspiratory burst through activation of spinobulbar pathways. We suggest that respiratory patterns should be included as an outcome variable in preclinical studies of ISMS.Graphical abstract
Source: Respiratory Physiology and Neurobiology - Category: Respiratory Medicine Source Type: research