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Circadian rhythm of melatonin and prostaglandin in modulation of stress-induced gastric mucosal lesions in rats

  1. K. Kato1,
  2. I. Murai2,
  3. S. Asai3,
  4. Y. Takahashi3,
  5. T. Nagata3,
  6. S. Komuro1,
  7. S. Mizuno1,
  8. A. Iwasaki1,
  9. K. Ishikawa4,
  10. Y. Arakawa1

Article first published online: 20 APR 2002

DOI: 10.1046/j.1365-2036.16.s2.11.x

Issue

Alimentary Pharmacology & Therapeutics

Alimentary Pharmacology & Therapeutics

Volume 16, Issue Supplement s2, pages 29–34, April 2002

Additional Information

How to Cite

Kato, K. , Murai, I. , Asai, S. , Takahashi, Y. , Nagata, T. , Komuro, S. , Mizuno, S. , Iwasaki, A. , Ishikawa, K. and Arakawa, Y. (2002), Circadian rhythm of melatonin and prostaglandin in modulation of stress-induced gastric mucosal lesions in rats. Alimentary Pharmacology & Therapeutics, 16: 29–34. doi: 10.1046/j.1365-2036.16.s2.11.x

Author Information

  1. 1

    Third Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan,

  2. 2

    Department of Biochemistry, Nihon University School of Medicine, Tokyo, Japan,

  3. 3

    Advanced Medical Research Center, Nihon University School of Medicine, Tokyo, Japan,

  4. 4

    Department of Pharmacology, Nihon University School of Medicine, Tokyo, Japan

* Dr K. Kato, 3rd Department of Internal Medicine, Nihon University School of Medicine, 30-1 Oyaguchi Kami machi, Itabashi-ku, Tokyo 173-8610, Japan. E-mail: kimitosi@med.nihon-u.ac.jp

Publication History

  1. Issue published online: 20 APR 2002
  2. Article first published online: 20 APR 2002

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Background:

We previously demonstrated the circadian variation of water-immersion restraint stress (WRS)-induced gastric mucosal lesions in rats.

Aim:

To investigate the roles of melatonin and prostaglandin in the gastric mucosa in circadian modulation of WRS.

Methods:

Fasted rats were subjected to 4-h WRS during both the diurnal and nocturnal phases of a light/dark cycle. Mucosal lesions, serum melatonin concentrations, mucosal generation of prostaglandin E2 (PGE2) and mucosal gene expressions of cyclooxygenase (COX)-1 and -2 were evaluated.

Results:

Lesion area after 4-h stress during the dark phase was significantly smaller than that in light-phase controls. Serum melatonin concentration in control rats during the light phase was significantly increased 4 h after WRS, but PGE2 generation was decreased by 48% as compared to that in intact mucosa before stress. In the dark phase, melatonin concentration after 4-h WRS was significantly depressed as compared with the control level at the corresponding time. PGE2 concentrations after 4-h WRS in the dark phase were not decreased compared with the control level at the corresponding time, although PGE2 level was significantly lower than that in light-phase controls. Expression of COX-1 and COX-2 mRNA was detected after exposure to stress in both the light and dark phases.

Conclusion:

These results suggest that circadian rhythm has an important role in the formation of stress-induced gastric mucosal lesions in rats. The circadian rhythm of melatonin responses and PGE2 generation may contribute to nocturnal/diurnal rhythmicity of gastric mucosal defences between day and night.

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