CARDIOVASCULAR STUDIES WITH IMPROMIDINE (SK-AND-F-92676), A NEW VERY POTENT AND SPECIFIC HISTAMINE H-2-RECEPTOR AGONIST

Impromidine (SK & F 92676) has recently been identified as a potent and specific histamine H2‐receptor agonist. The present paper describes some cardiovascular studies with the drug. Impromidine lowers blood pressure in cats and rats by interaction with H2‐receptors. During continuous intravenous infusions of impromidine, the fall in blood pressure is due to a reduction in total peripheral resistance; cardiac output increases during hypotension. The responses to impromidine are similar to responses to histamine in mepyramine‐treated cats. Impromidine administered intra‐arterially also causes vasodilatation in the femoral and mesenteric vasculature by interaction with H2‐receptors. Impromidine stimulates all measured parameters including coronary flow in the isolated working heart of the guinea‐pig. Dose‐response curves to impromidine were displaced to the right in the presence of cimetidine. 1979 Royal Pharmaceutical Society of Great Britain