B OH B 6B OH HO HO HO. a B B a HC-CH2-NH2 C HC-CH2-NH B HC-CH2-NH OH OL a OH CH3 OH HC-CH内 Norepinephrine Epinephrine laoproterenol CH3 a a 意 a a a A.Chemical structure of catecholamines and affinity for 0-and B-receptors Receptor affinity OH Catecholamine- O-methyltransferase Penetrability H through I+H Metabolic membrane barriers H地-N6 stability CH3 (Enteral abeorbability ◆OH CNS permeability) Monoamine oxidase
Catecholamines 。Natural Norepinephrine:a,B -Epinephrine:o,β -Dopamine:D,i,β，(also some NE release) ·Synthetic Isoproterenol:B Dobutamine:B (and mix of B2 stimulation and a inhibition and stimulation)
Catecholamines • Natural – Norepinephrine: , 1 – Epinephrine: , – Dopamine: D, 1 , 1 (also some NE release) • Synthetic – Isoproterenol: – Dobutamine: 1 (and mix of 2 stimulation and 1 inhibition and stimulation)