-A.Adrenergic transmission 3 Activates Adrenal Inhibits medulla Epinephrine(E) 0 Norepinephrine L-tyrosine Varicosities Bloodstream NE) L-dop阳 B-adrenoceptor Inactivated 2 (MAO) 1.Tyrosine hydroxylase Dopamine CAMP Action potential 2.Adenylyl cyclase PKA NE 6d 3.ATP,substance P az-adrenoceptor a2-adreno- ceptor Heart,glands. 4.Calcium channel smooth musde 6c 6b Inactivated: Re absorption by MAo by COMT Norepinephrine Epinephrine (NE) Capillary 6a Diffusion into blood (raises NE in blood) 0- adrenoceptors adrenoceptors PNorepinephrine (NE) 1.Tyrosine hydroxylase 2.Adenylyl cyclase 3.ATP, substance P 4.Calcium channel