Cimetidine and stress ulcer in aged rats.

Male Sprague-Dawley rats, 2, 6, 11, 18, and 26 months old, were subdivided into four drug treatment groups and received either 25, 50, 100 mg/kg of cimetidine or a placebo control before being exposed to restraint plus cold stress for 3 hr. Cimetidine, at all dose levels, significantly reduced ulcer severity in all age groups except the 18- and 26-month-old rats. Senescent rats were not more susceptible to restraint ulcer and cimetidine had the least anti-ulcer effect with the senescent 26-month-old rats.