Cerebellar injury induces NADPH diaphorase in Purkinje and inferior olivary neurons in the rat.
NADPH diaphorase (NADPH-D) histochemistry was examined following cerebellar lesions induced by stab or knife cuts. A population of Purkinje cells adjacent to the injury became NADPH-D positive after either type of lesion. These cells appeared by 3 days postlesion and were still seen after 6 weeks. Somata of reactive cells shrank gradually and were reduced about 38% in size by 6 weeks after lesion. In the inferior olive of animals subjected to cerebellar knife cut, NADPH-D-positive cells were found in the beta nucleus, dorsal cap, and subnucleus C. These cells became NADPH-D positive 5 days postlesion, were shrunken at 4 weeks postlesion, and were reduced about 26% in somata size by 6 weeks after lesion. Other cerebellar afferents did not exhibit obvious NADPH-D induction following these lesions. In unlesioned animals, no Purkinje cells or inferior olivary neurons were NADPH-D positive. The present study demonstrates that cerebellar damage induces NADPH-D, a marker for nitric oxide (NO) synthase, in Purkinje cells and inferior olivary neurons. In addition, these reactive neurons exhibit long-term degenerative changes. Taken together with previous studies, these findings indicate that NO, produced by the lesion-induced nitric oxide synthase (NOS), may contribute to the degeneration of brain neurons after injury. The lack of NADPH-D-positive neurons in either Purkinje or the inferior olivary neurons in nonlesioned animals indicates that this may provide a useful model system to study injury-induced NOS in brain.
Chen
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S
Department of Mental Health Sciences, Hahnemann University, Philadelphia, Pennsylvania 19102.
Aston-Jones
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G
D000818:Animals; D001930:Brain Injuries / Q000201:enzymology* / Q000473:pathology; D002531:Cerebellum / Q000293:injuries* / Q000473:pathology; D003712:Dendrites / Q000648:ultrastructure; D004790:Enzyme Induction; D008297:Male; D009252:NADPH Dehydrogenase / Q000096:biosynthesis*; D009474:Neurons / Q000201:enzymology* / Q000473:pathology; D009847:Olivary Nucleus / Q000201:enzymology* / Q000473:pathology; D011689:Purkinje Cells / Q000201:enzymology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D009252:NADPH Dehydrogenase