Acute effects of vagus nerve stimulation parameters on gastric motility assessed with magnetic resonance imaging. Issue 7 (15th April 2020)

• Record Type: Journal Article
• Authors: Lu, Kun‐Han; Cao, Jiayue; Phillips, Robert; Powley, Terry L.; Liu, Zhongming
• Is Part Of: Neurogastroenterology & motility. Volume 32:Issue 7(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-15
• Subjects: gastric motility -- magnetic resonance imaging -- rat -- vagus nerve stimulation; Gastrointestinal system -- Motility -- Periodicals; Gastrointestinal system -- Innervation -- Periodicals; 616.33
• DOI: 10.1111/nmo.13853
• Languages: English
• ISSNs: 1350-1925

Abstract

Abstract: 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 < .05 for 5 Hz, R = −.85, P < .05 for 10 Hz). The VNS with either polarity tended to promote pyloric motility to a greater extent given increasing stimulus intensity. Conclusions and Inferences: Monophasic VNS biased toward the afferent pathway is potentially more effective for facilitating occlusive contractions than that biased toward the efferent pathway. Abstract : We investigated a possible differential effect of primarily afferent versus efferent cervical VNS on gastric motility under a range of VNS parameters. Gastric MRI data revealed that primarily afferent VNS induced stronger antral contractions relative to primarily efferent VNS. These results could serve as an index for optimizing VNS parameters for promoting gastric motility.