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J Smooth Muscle Res. 2018;54(0):91-99. doi: 10.1540/jsmr.54.91.

GABAergic and glutamatergic neurons in the brain regulate phase II of migrating motor contractions in the Suncus murinus.

Author information

1
Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan.
2
Faculty of Pharmaceutical Sciences, Department of Pharmaceutical and Health Sciences, Josai University, 1-1 Keiyaki dai, Sakado, Saitama 350-0295, Japan.
3
Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.

Abstract

Gastric contractions exhibit characteristic motor patterns in the fasted state, known as migrating motor contractions (MMC). MMC consist of three periodically repeated phases (phase I, II and III) and are known to be regulated by hormones and the autonomic and enteric nervous systems. However, the central regulation of gastric contractions in the fasted state is not completely understood. Here, we have examined the central effects of motilin, ghrelin, γ-aminobutyric acid (GABA) and L-glutamate signaling on gastric MMC by using suncus (Suncus murinus) as an animal model, because of their similar gastric motor patterns to those observed in humans and dogs. Intracerebroventricular (i.c.v.) administration of motilin and ghrelin had no effect on phase I and II contractions, respectively. Conversely, i.c.v. administration of GABAA receptor antagonist, during phase I of the MMC, evoked phase II-like contractions and significantly increased the motility index (MI). This was compared with the i.c.v. administration of GABA which inhibited spontaneous phase II contractions with a significantly decreased MI. In addition, i.c.v. administration of L-glutamate during phase I also induced phase II-like irregular contractions with a significant increase in the MI. Taken together with previous findings, these results suggest that central GABAergic and glutamatergic signaling, with the coordination of both peripheral motilin and ghrelin, regulate phase II contractions of MMC in the fasted state.

KEYWORDS:

GABA; Suncus murinus; ghrelin; glutamate; motilin

PMID:
30787212
PMCID:
PMC6380905
DOI:
10.1540/jsmr.54.91
[Indexed for MEDLINE]
Free PMC Article

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