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Mechanism of delayed gastric emptying in naturally occurring CCK-A receptor gene knockout (OLETF) rats

M Ohta1, S Kanai, Y Sato

  • 1Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015 Japan.

The Japanese Journal of Physiology
|November 18, 2000
PubMed

Insights

Obesity-prone OLETF rats exhibit delayed gastric emptying due to increased sympathetic nerve activity, not impaired stomach muscle function. This suggests a novel mechanism for slowed digestion in these rats.

Area of Science:

  • Physiology
  • Gastroenterology
  • Endocrinology

Background:

  • Obesity-prone OLETF rats genetically lack CCK-A receptor expression.
  • These rats exhibit delayed gastric emptying, but the underlying mechanism is unclear.

Purpose of the Study:

  • To investigate the mechanism of delayed gastric emptying in OLETF rats.
  • To determine if impaired stomach smooth muscle function or altered nerve activity contributes to delayed gastric emptying.

Main Methods:

  • Gastric emptying was assessed in OLETF and control LETO rats using a phenol red liquid meal.
  • Reserpine was administered to evaluate its effect on gastric emptying in both rat strains.
  • Plasma noradrenaline levels were measured.
  • In vitro stomach smooth muscle contractility and muscle thickness were examined.

Main Results:

  • OLETF rats showed significantly delayed gastric emptying compared to LETO rats.
  • Higher doses of reserpine were needed to enhance gastric emptying in OLETF rats.
  • Plasma noradrenaline levels were elevated in OLETF rats.
  • Stomach smooth muscle function and thickness were comparable between OLETF and LETO rats.

Conclusions:

  • Delayed gastric emptying in OLETF rats is not due to impaired stomach smooth muscle function.
  • Increased sympathetic nerve function, indicated by higher plasma noradrenaline, is suggested as the cause of delayed gastric emptying in OLETF rats.

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