Elsevier Inc. epineprhine signaling pathway via afrenergic receptor beta Pnmt Dbh Ddc Th Qdpr epinephrine --+> epineprhine signaling pathway via afrenergic receptor beta S-adenosylmethionine ---> epinephrine norepinephrine ---> epinephrine norepinephrine Slc18a2 ---> dopamine Slc18a2 Ddc ---- Slc18a2 Slc18a2 ---- Th dopamine L-DOPA diet L-Phe hydroxylation BH4 BH2 tyrosine BH4 ---> BH2 L-DOPA ---> dopamine tyrosine ---> L-DOPA diet ---> tyrosine L-Phe hydroxylation ---> tyrosine BH2 ---> BH4 dopamine ---> norepinephrine epinephrine S-adenosylmethionine