Histamine is a substance released by the body's immune system from cells called mast cells. This occurs in response to injury or allergies. Histamine receptors are the proteins on cells found in the brain, blood vessels, lungs, skin and stomach that bind to histamine in order to produce an inflammatory response. The symptoms of the inflammatory response are red and watery eyes, swelling of the body, itching, rash or wheal and flare of the skin, stomach upset, congestion and runny nose, along with sneezing, coughing, and shortness of breath. Histamine blockers, or antihistamines, are medications that prevent the binding of histamine to its receptors within the body, and thereby inhibit or lessen these symptoms. Three types of histamine receptors are affected by these drugs called H1-, H2-, and H3--receptors. While H1-receptors are more widespread in the body, H2-receptors are found largely in the stomach and H3-receptors are in the brain. H1-blockers prevent or reduce severe allergic reactions, allergy-induced runny nose called allergic rhinitis, sinus congestion, and rash. H2-blockers decrease heartburn-related conditions like acid reflux called gastroesophageal reflux disease or GERD, where acid or food regurgitates back from the stomach into the throat, and peptic ulcers, which are sores in the stomach's lining resulting from excessive secretion of stomach acid. H3-blockers are still being studied in conditions involving the brain and sleep. (see references 5, 7 and 9).
Studies with opioid antagonists clearly indicate that morphine and other narcotic analgesics act at all levels of the central nervous system and in the peripheral nervous system, and that whatever their mode of action, it is on a very fundamental, basic, and widespread neuronal process. Audience Reviews for Blockers. May 16, 2019. Agonizingly painful jokes, cringe-worthy gags but a surprising amount of sentiment and heart to admire; Blockers is a fair effort comedy with.