Why Americans say epinephrine and Europeans say adrenaline
The same hormone carries two names because of a trademark. John Abel extracted it from adrenal glands in 1897 and called it epinephrine; Jōkichi Takamine patented a purified version in 1901, sold as Adrenalin. American drug naming sidestepped the brand, and the split between the two words has lasted ever since.
Both names say the same thing in different languages. Adrenaline comes from Latin for "on the kidney", epinephrine from Greek for "upon the kidney", a nod to the adrenal glands perched atop the kidneys. Because Adrenalin was registered by Parke, Davis and Company in the United States, and because Abel's extract was assumed to be identical to Takamine's, a belief historians now question, epinephrine became the official American generic name. European scientists mostly prefer adrenaline, yet even in America the receptors it acts on are called adrenergic.
The hormone is made mainly in the inner part of the adrenal glands, the medulla, which supplies more than 90 percent of what circulates in the blood; a few neurons in the brainstem also produce it. Walter Cannon linked it to the fight-or-flight response, and it does raise heart output, send blood to muscles, widen the pupils and lift blood sugar by binding to alpha and beta receptors. Surprisingly, people whose adrenal glands have been removed still handle exercise and low blood sugar normally, so the medulla is not essential for survival. And the main chemical messenger of the sympathetic nerves turned out to be noradrenaline, as Ulf von Euler showed in 1946.
Adrenaline also shapes memory. Emotionally stressful events trigger its release, which helps consolidate memories roughly in proportion to how important the event felt. In one experiment, people given injections of it reacted to frightening films with more negative expressions and reported stronger fear than those who were not. Researchers suspect a role in fear memory in conditions such as post-traumatic stress disorder.
Its reach extends well beyond humans. Many animals make it, as do some single-celled organisms, and it has even been isolated from Scoparia dulcis, a plant growing in northern Vietnam. As a medicine it is used for anaphylaxis, cardiac arrest and croup, and for decades the way to measure its tiny concentrations in blood was itself a scientific challenge, solved by radio-enzymatic assays sensitive to a single picogram.
Source: Adrenaline
