Cardiovascular and Behavioral Actions of Centrally Administered Cimetidine

Publisher Website
Google Scholar
Abstract
[Cimetidine is a histamine H2 receptor antagonist used extensively in the treatment or gastrointestinal disorders.] The cardiovascular and behavioral actions of cimetidine, injected into the lateral ventricle, were studied in conscious, freely moving rats. Cimetidine produced a dose-dependent pressor response accompanied by decreases in heart rate and increases in pulse pressure. At dose of 25-100 .mu.g, cimetidine produced sedation; however, when 200 .mu.g was injected, tremor was observed in all animals. If cimetidine was administered twice within 30 min to the same animal, tachyphylaxis in response to any of these actions was never evident. Although histamine produced similar pressor actions when administered intraventricularly, these effects were always subject to tachyphylaxis. The actions of cimetidine were not altered by central pretreatment with the H1 antagonist chlorpheniramine. A possible hypothesis of the central mechanism by which cimetidine produces these effects is discussed.