morphine ( 0.5-1.0 mg/kg ) was used as the prototype opiate , beta-endorphin ( beta-end ; 10-20 micrograms/kg ) and [ d-ala2 , d-leu5 ] enkephalin ( dadle ; 5-20 micrograms/kg ) were used as representatives of eop , and naloxone ( 0.5-2.0 mg/kg ) was used as an opiate receptor blocker .
C0014298
enkephalin
C0205753
eop