Jpn. J. Pharmacol. 85 (2), 189-196 (2001)

Anxiety-Like Behavior in Elevated Plus-Maze Tests in Repeatedly Cold-Stressed Mice

Taeko Hata*, Hiroyuki Nishikawa, Eiji Itoh and Yoshinori Funakami

Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
*Corresponding author. FAX: +81-6-6721-2353

Abstract: To clarify the relationship between SART (specific alternation of rhythm in temperature) stress (repeated cold stress) and anxiety, the effects of various types of stress on the behavior of mice were studied in elevated plus-maze tests and then the effects of anxiolytics were evaluated. The percentage of time spent in the open arms of the plus-maze apparatus decreased in mice subjected to SART stress without change in the total number of arm entries. No change was noted in mice subjected to other stresses, such as 1-h, 2-day and 5-day cold stress and 1-h, 15-h and 5×15-h restraint stress. The reduction in the percentage of time spent in the open arms caused by SART stress was inhibited by single and repeated administrations of diazepam and alprazolam and by a single administration of buspirone, which have no influence on the percentage of time spent in the open arms in nonstressed mice, but not by flumazenil, WAY-100635 and chronic treatment with buspirone. The effects of diazepam and buspirone were antagonized by flumazenil and WAY-100635, respectively. The behavior of SART-stressed mice in the plus-maze would thus appear to arise from anxiety, to which benzodiazepine and serotonin receptors are related, but the diazepam binding inhibitor, an endogenous anxiogenic protein, is not. Thus SART-stressed animals may be useful for investigating the psychopharmacological and neuropharmacological basis of anxiety.

Keywords: Elevated plus-maze, Stress, SART stress, Anxiety, Repeated cold stress

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