in unanesthetized sponatneously hypertensive rats ( shr ) , naloxone ( 0.5 -- 2 mg/kg ip . ) or naltrexone ( 2 mg/kg ) inhibited the hypotension and bradycardia produced by clonidine ( 5 -- 20 micrograms/kg iv . ) .
C0027358
naloxone
C0027360
naltrexone