Epinephrine (adrenaline)

A "fight-or-flight" neurotransmitter secreted by the sympathetic nervous system. Effects include enhanced cardiac contractility, tachycardia, vasoconstriction, and bronchodilation. Endogenous epinephrine is secreted by the adrenals, brainstem, and the sympathetic nervous system. Epinephrine is also administered for the emergency management of bradycardia, hypotension, and allergic reactions. Known as adrenaline in Commonwealth countries.