Acute effects of vagus nerve stimulation parameters on gastric motility assessed with magnetic resonance imaging

• Published in: Neurogastroenterology and motility 2020-07, Vol.32 (7), p.e13853-n/a
• Main Authors: Lu, Kun‐Han, Cao, Jiayue, Phillips, Robert, Powley, Terry L., Liu, Zhongming
• Format: Article
• Language: English
• Subjects: Action potential; Acute effects; Electrical stimuli; Food intake; Gadolinium; Gastric motility; Magnetic resonance imaging; Motility; Polarity; rat; Rodents; Sensory neurons; Vagus nerve; vagus nerve stimulation
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/nmo.13853

Background Vagus nerve stimulation (VNS) is an emerging bioelectronic therapy for regulating food intake and controlling gastric motility. However, the effects of different VNS parameters and polarity on postprandial gastric motility remain incompletely characterized. Methods In anesthetized rats (N = 3), we applied monophasic electrical stimuli to the left cervical vagus and recorded compound nerve action potential (CNAP) as a measure of nerve response. We evaluated to what extent afferent or efferent pathway could be selectively activated by monophasic VNS. In a different group of rats (N = 13), we fed each rat a gadolinium‐labeled meal and scanned the rat stomach with oral contrast‐enhanced magnetic resonance imaging (MRI) while the rat was anesthetized. We evaluated the antral and pyloric motility as a function of pulse amplitude (0.13, 0.25, 0.5, 1 mA), width (0.13, 0.25, 0.5 ms), frequency (5, 10 Hz), and polarity of VNS. Key Results Monophasic VNS activated efferent and afferent pathways with about 67% and 82% selectivity, respectively. Primarily afferent VNS increased antral motility across a wide range of parameters. Primarily efferent VNS induced a significant decrease in antral motility as the stimulus intensity increased (R = −.93, P