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Enhanced sympathetic nerve activity induced by neonatal colon inflammation induces gastric hypersensitivity and anxiety-like behavior in adult rats

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AJP Gastrointestinal and Liver Physiology

Published online on

Abstract

Gastric hypersensitivity (GHS) and anxiety are prevalent in Functional Dyspepsia patients; their underlying mechanisms remain unknown largely because of lack of availability of live visceral tissues from human subjects. Recently, we demonstrated in a preclinical model that rats subjected to neonatal colon inflammation show increased basal plasma norepinephrine, which contributes to GHS through the up-regulation of nerve growth factor (NGF) expression in the gastric fundus. We tested the hypothesis that neonatal colon inflammation increases anxiety-like behavior and sympathetic nervous system (SNS) activity, which upregulates the expression of NGF to induce GHS in adult-life (GHS-rats). Chemical sympathectomy, but not adrenalectomy, suppressed the elevated NGF expression in the fundus muscularis externa and gastric hypersensitivity. The measurement of heart rate variability showed a significant increase in the LF/HF ratio in GHS vs. the control rats. Stimulus-evoked release of NE from the fundus muscularis externa strips was significantly greater in GHS vs. the control rats. Tyrosine hydroxylase expression was increased in the celiac ganglia of the GHS vs. the control rats. We found an increase in trait but not stress-induced anxiety-like behavior in GHS-rats in elevated plus maze. We concluded that neonatal programming triggered by colon inflammation upregulates tyrosine hydroxylase (TH) in the celiac ganglia, which upregulates the release of NE in the gastric fundus muscularis externa. The increase of NE release from the sympathetic nerve terminals concentration-dependently upregulates NGF, which proportionately increases the visceromotor response to gastric distension. Neonatal programming concurrently increases anxiety-like behavior in GHS-rats.