methionine-enkephalin ( me ) , leucine-enkephalin ( le ) , phe-met-arg-phe amide ( fmrfamide ) , d-ala2 , n-methyl-phe4 , met ( o ) 5-ol-enkephalin ( fk 33-834 ) , methionine-enkephalin arg6 arg7 ( me arg6 arg7 ) and beta-endorphin had no effect on basal beating rate of isolated atria at all concentrations up to 10 ( -5 ) m .
C0014294
leucine-enkephalin
C0014298
enkephalin