Expression of nitric oxide synthase isoforms in spinal cord in amyotrophic lateral sclerosis.
METHODS
Autoradiography with [3H]nitro-L-arginine (3HL-NNA) was used to quantify nitric oxide synthase (NOS), and immunocytochemistry to identify NOS isoforms, in spinal cord in amyotrophic lateral sclerosis (ALS) and controls.


RESULTS
In controls NOS binding was marked only in the superficial dorsal horn, but in ALS tissue it was intense throughout the grey and white matter. A single population of binding sites was indicated in controls, but two populations in ALS. In the controls intense neuronal NOS (nNOS) immunoreactivity was present in numerous cells in the dorsal horn, and faint immunoreactivity in small and medium-sized cells in the ventral horn. Only weak immunoreactivity for inducible NOS (iNOS) and endothelial NOS (eNOS) was detectable in control tissue. In ALS, the pattern was broadly similar in the grey matter, but immunoreactivity for both nNOS and iNOS was present in white matter.


CONCLUSIONS
Expression of abnormal variants of nNOS or increased expression of iNOS may have a role in motoneuron death in ALS.
Phul
R K
RK
Department of Physiology, Medical School, University of Birmingham, UK.
Shaw
P J
PJ
Ince
P G
PG
Smith
M E
ME
D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000473:pathology; D001345:Autoradiography; D002452:Cell Count; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000201:enzymology / Q000473:pathology; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000096:biosynthesis*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000378:metabolism / Q000494:pharmacology; D013116:Spinal Cord / Q000201:enzymology* / Q000473:pathology; D014316:Tritium
D004791:Enzyme Inhibitors; D014316:Tritium; D019335:Nitroarginine; C496320:NOS1 protein, human; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III