epinephrine

1. (biochemistry, organic chemistry, medicine) A catecholamine hormone and neurotransmitter; as a hormone, secreted by the adrenal gland in response to stress (when it stimulates the autonomic nervous system); as a neurotransmitter, synthesized from norepinephrine. It is also used as a medication.Examples: "At the ER, after deflating me with a cocktail of epinephrine, a steroid and an antihistamine, the doctors scolded me for not coming in more quickly: I could have died of asphyxiation."; "“Anyone who has experienced or witnessed an anaphylaxis reaction knows it can be very stressful deciding when to inject epinephrine to themselves or a child and often delay,” Dr. Jonathan Spergel, chief of the allergy program at Children’s Hospital of Philadelphia, said in a news release from ARS Pharmaceuticals."Synonyms: adrenaline, 4, 5-β-trihydroxy-N-methylphenethylaminecountableuncountable