Light microphotographs demonstrating the effect of the NMDA antagonist
CPP on slowly progressing neurodegeneration induced in the striatum by
systemic administration of 3NP and in the hippocampus by traumatic
brain injury. (A) Morphology of striatum after treatment
with 3NP, 12 mg/kg per d over 28 days, 3 days after termination of
treatment. No obvious neurodegeneration can be detected in the
striatum; the spiny neurons have normal appearance. (B)
Profound neuronal loss and predominance of glia in the striatum 3 days
after termination of treatment with 3NP, 12 mg/kg per d, and CPP, 24
mg/kg per d over 28 days. Large-size striatal neurons are relatively
preserved. (C) Hippocampal pathology in the CA3 subfield
3 days after traumatic brain injury. Dark argyrophylic profiles
indicate ongoing degeneration in pyramidal layer. Intact pyramidal
cells with prominent nuclei are also present. (D) The
effect of treatment with CPP, 3 × 30 mg/kg given i.p. 1, 2, and
3 h after trauma is shown. Widespread degeneration of pyramidal
neurons predominates. Magnifications: A and
B, ×60 (cresyl violet stain); C and
D, ×80 (Fink and Heimer stain).