Induction of NADPH-diaphorase/nitric oxide synthase in the brainstem trigeminal system resulting from cerebellar lesions.
Recent evidence indicates that NADPH-diaphorase (NADPH-d) and nitric oxide synthase (NOS) can be induced in cerebellar afferent neurons following mechanical, thermal, or chemical damage to the cerebellar cortex (Saxon and Beitz [1994] Neuroreport 5:809-812). The present study reports on the induction of NADPH-d/NOS in neurons of the brainstem trigeminal complex (BVC). Three groups of rats were used: Group I received a unilateral glass micropipette lesion into the vermal/paravermal region of the cerebellar cortex, group II received a concurrent injection of fluoro-gold along with the pipette lesion, and in group III the cerebellar cortex on one side was aspirated. Following survival times of 7-120 days, animals were processed for NADPH-d histochemistry. All three groups showed projection-specific induction of NADPH-d in different regions of the brainstem trigeminal complex. Induced neurons were distributed throughout the ipsilateral subnucleus interpolaris, principal trigeminal nucleus, and intertrigeminal nucleus. Subnucleus oralis contained a small number of induced neurons localized to the ipsilateral dorsomedial portion of the subnucleus. Projection-specific induction was confirmed by the presence of neurons double-labeled for NADPH-d and Fluoro-Gold. Although the functional consequences of NADPH-d/NOS induction remain to be elucidated, the induction of these enzymes in precerebellar neurons suggests that nitric oxide may play a role in the neuronal response to target specific lesions.
Saxon
D W
DW
Department of Vet/Pathobiology, University of Minnesota, St. Paul 55108, USA.
Beitz
A J
AJ
D000818:Animals; D001933:Brain Stem / Q000201:enzymology*; D002525:Cerebellar Cortex / Q000502:physiology*; D004790:Enzyme Induction; D005456:Fluorescent Dyes; D008297:Male; D009252:NADPH Dehydrogenase / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013266:Stilbamidines; D014279:Trigeminal Nucleus, Spinal / Q000201:enzymology*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D005456:Fluorescent Dyes; D013266:Stilbamidines; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase