<prompt> All are endogenous catecholamines except:EpinephrineNorepinephrineDopamineDobutamine  <response>: Ans. is d i.e. Dobutamine Catecholamines are compound containing catechol nucleus and a side chain containing amine group. EndogenousSynthetic Epinephrine Isoprenaline Norepinephrine Dipivefrin Dopamine Dobutamine Serotonin Ibopamine Histamine Dopexamine FenoldopamActions of various catecholamine Adrenaline Epinephrine- a1 a2 b1 b2 weak b3 Noradrenaline Norepinephrine- a1 a2 b1 b3 but no b2 action IsoprenalineB1 b2 b3 but no a action Dopamine- b1 a D1 D2 but no b2 Dobutamine- a b no D1 or D2 considered selective b1 