Guinea-pig sympathetic postganglionic neurones contain haem oxygenase-2.
HAEM oxygenase-2 (HO-2) is the neuronal isoform of the only known mammalian enzyme generating the new transmitter candidate, carbon monoxide. Its distribution was investigated in the sympathetic nervous system. A 36 kDa HO-2 immunoreactive protein was identified in the particulate fraction of stellate ganglion and cerebellum in Western blots. Immunohistochemically, all noradrenergic and non-noradrenergic postganglionic neurones were HO-2 immunoreactive in prevertebral ganglia and cervical, thoracic, and lumbar sympathetic chain ganglia. Neither postganglionic nerve branches nor noradrenergic perivascular terminals were HO-2 immunoreactive under control conditions. However, accumulation of HO-2 immunoreactivity was found in noradrenergic axons in explanted sciatic nerves in which axonal transport was interrupted by crushing. We conclude that HO-2 is ubiquitous in perikarya of postganglionic sympathetic neurones, is subjected to axonal transport but does not accumulate at sympathetic neuroeffector junctions. This distribution favours a general role of HO-2 in sympathetic neuronal metabolism rather than a specific association with transmission at autonomic neuroeffector junctions.
Vollerthun
R
R
Institute for Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany.
Höhler
B
B
Kummer
W
W
D000818:Animals; D001369:Axons / Q000201:enzymology; D002248:Carbon Monoxide / Q000378:metabolism; D006224:Cricetinae; D006419:Heme Oxygenase (Decyclizing) / Q000032:analysis*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000032:analysis*; D008970:Molecular Weight; D009474:Neurons / Q000201:enzymology*; D017779:Sympathetic Fibers, Postganglionic / Q000166:cytology / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D007527:Isoenzymes; D002248:Carbon Monoxide; D006419:Heme Oxygenase (Decyclizing); D014446:Tyrosine 3-Monooxygenase