An antihistamine is a type of pharmaceutical drug that opposes the activity of histamine receptors in the body.Antihistamines are subclassified according to the histamine receptor that they act upon: the two largest classes of antihistamines are H1-antihistamines and H2-antihistamines.n H3-antihistamine is a classification of drugs used to inhibit the action of histamine at the H3 receptor. H 3 receptors are primarily found in the brain and are inhibitory autoreceptors located on histaminergic nerve terminals, which modulate the release of histamine.
U.S. Secret Service. U.S. Secret Service, federal law-enforcement agency within the United States Department of Homeland Security tasked with the criminal investigation of counterfeiting and other financial crimes. After the assassination of Pres.
The real British Secret Service is called the Secret Intelligence Service (SIS) although it is commonly known as MI6 (the designation from GoldenEye onwards). It is responsible for intelligence activities outside of the UK and as such can be equated to the US CIA at a simplistic level.n the novels and the subsequent movies Bond's boss, the head of the Secret Service, is known as M. Fleming based this on the real Secret Service, whose head was known by the designation C after the original director general of MI6, Sir Mansfield Cumming.