Identification of cells undergoing physiological neuronal death in the neonatal rat brain by the Fink-Heimer method

There are certain limitations in identifying cells undergoing physiological neuronal death (PND) by conventional histological methods. Here, the Fink-Heimer method for impregnation of degenerating axons and terminals was successfully employed in selectively visualizing PND in the neonatal rat brain. The cell bodies thus observed were in close correlation with the known distribution and time-course of PND. In addition, massive occurrences of PND were observed in the periaqueductal gray, inferior colliculus, hypothalamus, and the rostral portion of the hippocampus, findings hitherto undescribed. Thus, the Fink-Heimer method provides a useful adjunct to the study of PND in the neonatal period.