morphine ( 1 x 10 ( -8 ) - 1 x 10 ( -4 ) m ) , fentanyl ( 1 x 10 ( -9 ) - 1 x 10 ( -5 ) m ) and alfentanyl ( 1 x 10 ( -10 ) - 1 x 10 ( -5 ) m ) as well as methionine enkephalin [ met5 ] enkephalin ( 1 x 10 ( -11 ) - 1 x 10 ( -8 ) m ) , [ d-ala2 , met5 ] enkephalin ( 1 x 10 ( -12 ) - 1 x 10 ( -8 ) m ) and dynorphin a ( 1 - 13 ) ( 1 x 10 ( -9 ) - 1 x 10 ( -6 ) m ) caused a contractor response of the longitudinal musculature of the terminal colon of the mouse .
C0015846
fentanyl
C0002026
alfentanyl