the noxiously evoked activity of all cells in the nrgc was suppressed by the administration of opioids ( by 58 and 88 % for fentanyl , 25 micrograms/kg and 50 micrograms/kg , respectively ; by 35 and 78 % for alfentanil 12.5 micrograms/kg and 25 micrograms/kg , respectively ) .
C0015846
fentanyl
C0002026
alfentanil