About adrenalinealpha and beta adrenergic agonist, catecholamine, vasoconstrictor., anti asthma, inanaphylatic shock.mechanism of action of adrenalineadrenaline is an alpha and beta adrenergic agonist which exerts it`s therapeutic actions through predominant beta receptor agonistic action. it is a positive inotropic and chronotropic drug and it increases stroke volume, cardiac output and improves coronary blood flow. it increases systolic and mean blood pressure. it increases blood flow to skeletal muscles. it is a powerful bronchial smooth muscle relaxant and antagonizes spasm of bronchial muscle. it acts through alpha receptors in skin, mucous membrane, and viscera and causes vasoconstriction and which reduces absorption of local anaesthetics localizes and prolongs the duration of anaesthesia. local vasoconstrictor action also produces haemostasis.role in local anaesthesia: