The mice were placed in a 50 mL conical polypropylene centrifuge tube and immersed vertically to the level of the xiphoid process into a water bath at 23°C for 2 hrs (acute stress). The mice were subjected to this stress session once a day for 3 weeks (chronic stress). In our preliminary experiments, gastric ulcer was not produced by single or chronic exposure. Control mice were similarly fasted, followed by removal from their home cages, and subsequent placement in new breeding cages for 2 hrs. These experimental groups were chosen by means of a completely randomized design. Depression-like behaviors were measured with tail-suspension test and forced-swimming test. Immobility time was recorded in both tests during the last 6 min in the total 10 min test-period. After the end of this stress session, the mice were anesthetized with administration of sodium pentobarbital (30 mg/kg). In chronic stress and control mice groups, to avoid the acute influence of the last stress session and to evaluate the influence of chronic stress as a consequence of the cumulative stress effects, mice were sacrified after 1 day from last stress session.
Free full text: Click here
