Adrenaline also called (Epinephrine or 4, 5-β- trihydroxy phenethylamine) was discovered as a substance produced from adrenal gland in 1886 by William Bates reported. After the discovery of adrenaline, it was isolated and recognized in 1895 by Napoleon Cybulski, then the adrenaline is synthesized artificially for the first time in 1904 by Friedrich Stolz.<br />Adrenaline consists of the amino group, an aromatic ring and a two-carbon chain, (-CH2-CH2-). Epinephrine classified in the class of compounds called catecholamine: is a monoamine derived from the amino acid tyrosine, and it also derived from phenylalanine, thereby it has the formula C6H13NO3. <br />At the present time, adrenaline is identified as a biogenic amine that acts as both neurotransmitters and hormone secreted by the inner part of the adrenal gland, above the kidneys, which is produced in the heart of the adrenal in response to physical or mental stress.<br />1- Adrenaline as a hormone: The Adrenaline is released when the sugar level in the blood is low, so it has the opposite effect of insulin (7, 8).<br /><br />2- Adrenaline as a neurotransmitter: Adrenaline works as a neurotransmitter affects the sympathetic nervous system in the heart, lungs, blood vessels, and the bladder.<br />The disorders in the Adrenal gland, make gland produce too much or not enough Adrenaline hormones that cause several diseases: Tumors of the adrenal gland, Addison's disease, Parkinson's disease, Cushing’s Syndrome, High blood pressure, High blood sugars, slow growth rates in children, etc.<br /><br /><br /> By: MSc Halla Thamer Mohammed