|
1
|
Lu KH, Cao J, Oleson S, Ward MP, Phillips R, Powley TL, Liu Z. Vagus nerve stimulation promotes gastric emptying by increasing pyloric opening measured with magnetic resonance imaging. Neurogastroenterol Motil 2018; 30:e13380. [PMID: 29797377 PMCID: PMC6160317 DOI: 10.1111/nmo.13380] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/18/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND Vagus nerve stimulation (VNS) is an emerging electroceutical therapy for remedying gastric disorders that are poorly managed by pharmacological treatments and/or dietary changes. Such therapy seems promising as the vagovagal neurocircuitry modulates the enteric nervous system to influence gastric functions. METHODS Here, the modulatory effects of left cervical VNS on gastric emptying in rats were quantified using a (i) feeding protocol in which the animal voluntarily consumed a postfast, gadolinium-labeled meal and (ii) a non-invasive imaging method to measure antral motility, pyloric activity and gastric emptying based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing pipelines. KEY RESULTS Vagus nerve stimulation significantly accelerated gastric emptying (sham vs VNS: 29.1% ± 1.5% vs 40.7% ± 3.9% of meal emptied per 4 hours), caused a greater relaxation of the pyloric sphincter (sham vs VNS: 1.5 ± 0.1 vs 2.6 ± 0.4 mm2 cross-sectional area of lumen), and increased antral contraction amplitude (sham vs VNS: 23.3% ± 3.0% vs 32.5% ± 3.0% occlusion), peristaltic velocity (sham vs VNS: 0.50 ± 0.02 vs 0.67 ± 0.03 mm s-1 ), but not its contraction frequency (sham vs VNS: 6.1 ± 0.2 vs 6.4 ± 0.2 contractions per minute, P = .22). The degree to which VNS relaxed the pylorus was positively correlated with gastric emptying rate (r = .5887, P < .001). CONCLUSIONS & INFERENCES The MRI protocol employed in this study is expected to enable advanced preclinical studies to understand stomach pathophysiology and its therapeutics. Results from this study suggest an electroceutical treatment approach for gastric emptying disorders using cervical VNS to control the degree of pyloric sphincter relaxation.
Collapse
Affiliation(s)
- Kun-Han Lu
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA
| | - Jiayue Cao
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA
| | - Steven Oleson
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Matthew P Ward
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA,Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert Phillips
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| | - Terry L Powley
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA,Correspondence: Zhongming Liu, PhD, Assistant Professor of Biomedical Engineering, Assistant Professor of Electrical and Computer Engineering College of Engineering, Purdue University, 206 S. Martin Jischke Dr. West Lafayette, IN 47907, USA, Phone: +1 765 496 1872, Fax: +1 765 496 1459, . Terry L Powley, PhD, Distinguished Professor of Behavioral Neuroscience, Department of Psychological Sciences, Purdue University, 703 Third Street, West Lafayette, IN 47907, USA, Phone: +1 765 494 6269,
| | - Zhongming Liu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA,School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA,Correspondence: Zhongming Liu, PhD, Assistant Professor of Biomedical Engineering, Assistant Professor of Electrical and Computer Engineering College of Engineering, Purdue University, 206 S. Martin Jischke Dr. West Lafayette, IN 47907, USA, Phone: +1 765 496 1872, Fax: +1 765 496 1459, . Terry L Powley, PhD, Distinguished Professor of Behavioral Neuroscience, Department of Psychological Sciences, Purdue University, 703 Third Street, West Lafayette, IN 47907, USA, Phone: +1 765 494 6269,
| |
Collapse
|
|
2
|
Uchida M, Kobayashi O, Saito C. Correlation Between Gastric Emptying and Gastric Adaptive Relaxation Influenced by Amino Acids. J Neurogastroenterol Motil 2017; 23:400-408. [PMID: 28335103 PMCID: PMC5503290 DOI: 10.5056/jnm16153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/04/2017] [Accepted: 01/15/2017] [Indexed: 02/01/2023] Open
Abstract
Background/Aims Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. Methods In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-13C] acetic acid. The expired 13CO2 pattern, Tmax, Cmax, and AUC120min values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. Results L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. Tmax showed a significant positive correlation (r = 0.709), and Cmax and AUC120min each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. Conclusion From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying.
Collapse
Affiliation(s)
- Masayuki Uchida
- Food Science Research Laboratories, Research and Development Division, Meiji Co, Ltd, Odawara, Kanagawa, Japan
| | - Orie Kobayashi
- Food Science Research Laboratories, Research and Development Division, Meiji Co, Ltd, Odawara, Kanagawa, Japan
| | - Chizuru Saito
- Food Science Research Laboratories, Research and Development Division, Meiji Co, Ltd, Odawara, Kanagawa, Japan
| |
Collapse
|