It causes contraction of smooth muscle, stimulates gastric secretion of hydrochloric acid and pepsin, and dilated blood vessels, which lowers blood pressure and produces inflammation, itching, or allergic symptoms; such as, sneezing.2. A chemical in the body tissues which is produced by the breakdown of histidine.
It is released in allergic reactions and causes widening of capillaries, decreased blood pressure, increased release of gastric juice, fluid leakage forming itchy skin and hives, and tightening of smooth muscles of the bronchial tube and uterus.3. An amine released by immune cells that produces allergic reactions.
Any organic derivative of ammonia formed by the replacement of hydrogen with one or more alkyl groups.
This type of agent acts by interfering with the action of histamine rather than by preventing its secretion.
It is used most frequently as a diagnostic agent in determining the acid-secreting power of the stomach.