the kinetics of four 11c-labelled enkephalin peptides : tyr-gly-gly-phe-met ( met-enkephalin ) , tyr-d-met-gly-phe-pro-nh2 [ d-met2 , pro5 ) -enkephalinamide ) , tyr-d-ala-gly-phe-met-nh2 ( dala ) and tyr-d-ala-d-ala-phe-met-nh2 ( taafm ) all labelled at the methyl group of methionine was studied in the rhesus monkey .
C0014298
enkephalin
C0014295
met-enkephalin