mice were exposed to whole-body irradiation ( 500 rads ) from a 137cs gamma-source and tested 2 h later for antinociception ( tail-flick test ) produced by intracerebroventricular administration of morphine or the more delta-selective opioid peptide , [ d-pen2 , l-pen5 ] enkephalin ( dplpe ) .
C0205753
opioid peptide
C0014298
enkephalin