the combination of horseradish peroxidase ( hrp ) histochemistry , enhanced by the use of cocl2 , with the unlabeled antibody , peroxidase-antiperoxidase ( pap ) immunocytochemical staining method , revealed double labeled cells containing black punctate hrp granules within a homogeneous brown cytoplasm stained positively for serotonin ( 5-ht ) , substance p or enkephalin-like immunoreactivity .
C0007634
cells
C0010834
cytoplasm