High gastrin cell activity and low ghrelin cell activity in high-anxiety Wistar Kyoto rats

    1. Erik Lindström1
    1. 1AstraZeneca R&D, Integrative Pharmacology, GI Biology, Mölndal, HF449, S-431 83, Sweden
    2. 2Department of Experimental Medical Science, Lund University, Lund, Sweden
    1. (Requests for offprints should be addressed to E Lindström; Email: erik.a.lindstrom{at}astrazeneca.com)


    Ghrelin is produced by gastric A-like cells and released in response to food deprivation. Interestingly, psychological stress also raises circulating ghrelin levels. This study compared plasma ghrelin levels in Sprague–Dawley (SPD) rats and high-anxiety Wistar Kyoto (WKY) rats. The two strains were also compared with respect to plasma gastrin, a gastric hormone with a pre- and postprandial release pattern opposite to that of ghrelin, and to the activity of the gastrin-dependent, histamine-forming ECL cells in the gastric mucosa. The rats were killed after being freely fed or after an over-night fast. The stomachs were weighed and tissue samples were collected for histological and biochemical analysis. Plasma ghrelin and gastrin levels were determined by RIA. While fasted SPD rats had higher plasma ghrelin levels than fasted WKY rats (P < 0.001), plasma ghrelin did not differ between freely fed rats of the two strains. Gastrin levels were higher in fed WKY rats than in fed SPD rats (P < 0.001). Despite the higher plasma gastrin level, the oxyntic mucosal histidine decarboxylase (HDC) activity (a marker of ECL-cell activity) in fed rats and the mucosal thickness did not differ between the two strains. In a subsequent study, rats were subjected to water-avoidance stress for 60 min, causing plasma gastrin to increase in WKY rats (P < 0.001) but not in SPD rats. In conclusion, high-anxiety WKY rats had lower circulating ghrelin and higher gastrin than SPD rats in both the fasted and fed state, while the ECL-cell activity (HDC activity) was only moderately affected.

    • Received in final form 26 February 2007
    • Accepted 7 March 2007
    • Made available online as an Accepted Preprint 9 March 2007
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