Epinephrine

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Epinephrine Pubchem(5816)

The active sympathomimetic hormone from the adrenal medulla in most species. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. It is used in asthma and cardiac failure and to delay absorption of local anesthetics.

Epinephrine (also referred to as adrenaline; see Terminology) is a hormone and neurotransmitter. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. The Latin roots ad-+renes and the Greek roots epi-+nephros both literally mean "on/to the kidney" (referring to the adrenal gland, which sits atop the kidneys and secretes epinephrine). Epinephrine is often shortened to E or to EPI in Medical jargon. Epinephrine increases the response of the sympathetic division of the Autonomic Nervous System.

History

Epinephrine was isolated and identified in 1895 by Napoleon Cybulski, a Polish physiologist. In May 1896, William Bates reported the discovery of a substance produced by the adrenal gland in the New York Medical Journal.<ref name="bates-eye">Template:Cite web</ref> The discovery was repeated in 1897 by John Jacob Abel.<ref>Aronson JK (2000). "Where name and image meet" - the argument for "adrenaline". British Medical Journal 320, 506-9.</ref>

Jokichi Takamine, a Japanese chemist, independently discovered the same hormone in 1900.<ref>Yamashima T (2003). "Jokichi Takamine (1854–1922), the samurai chemist, and his work on adrenalin". J Med Biogr 11 (2): 95–102. PMID 12717538. </ref><ref>Bennett M (1999). "One hundred years of adrenaline: the discovery of autoreceptors". Clin Auton Res 9 (3): 145–59. doi:10.1007/BF02281628. PMID 10454061. </ref> In 1901 he isolated and purified the hormone epinephrine from cow glands.

Epinephrine was first artificially synthesized in 1904 by Friedrich Stolz.

Triggers

Epinephrine is a "fight or flight" hormone, and plays a central role in the short-term stress reaction. It is released from the adrenal glands when danger threatens or in an emergency, hence an Adrenaline rush. Such triggers may be threatening, exciting, or environmental stressor conditions such as high noise levels, or bright light and high ambient temperature (see Fight-or-flight response).

Actions in the body

When in the bloodstream, it rapidly prepares the body for action in emergency situations. The hormone boosts the supply of oxygen and glucose to the brain and muscles, while suppressing other non-emergency bodily processes (digestion in particular).

It increases heart rate and stroke volume, dilates the pupils, and constricts arterioles in the skin and gastrointestinal tract while dilating arterioles in skeletal muscles. It elevates the blood sugar level by increasing catabolism of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in fat cells. Like some other stress hormones, epinephrine has a suppressive effect on the immune system.<ref name="omd">Epinephrine - Online Medical Dictionary</ref>

Although epinephrine does not have any psychoactive effects, stress or arousal also releases norepinephrine in the brain. Norepinephrine has similar actions in the body, but is also psychoactive.

The type of action in various cell types depends on their expression of adrenergic receptors.

KEGG Pathway(C00788,D00095)

• Tyrosine metabolism
• Neuroactive ligand-receptor interaction

Target

• alpha1a-adrenergic receptor agonist
• alpha1b-adrenergic receptor agonist
• alpha1d-adrenergic receptor agonist
• alpha2a-adrenergic receptor agonist
• alpha2b-adrenergic receptor agonist
• alpha2c-adrenergic receptor agonist
• beta1-adrenergic receptor agonist
• beta2-adrenergic receptor agonist
• beta3-adrenergic receptor agonist

Activity Adrenergic [vasoconstrictor]