title: Expression of nitric oxide synthase and guanylate cyclase in the human ciliary body and trabecular meshwork.
abstract: BACKGROUND
  The role played by the nitric oxide (NO) signaling pathway in the aqueous humor dynamics is still unclear. This study was designed to investigate the expression and distribution of NO synthase (NOS) isoforms and guanylate cyclase (GC) in human ciliary body, trabecular meshwork and the Schlemm's canal.
  
  
  METHODS
  Twelve eyes after corneal transplantation were used. Expression of three NOS isoforms (i.e. neuronal NOS (nNOS), inducible NOS (iNOS) and endothelial NOS (eNOS)) and GC were assessed in 10 eyes by immunohistochemical staining using monoclonal or polyclonal antibody of NOS and GC. Ciliary bodies were dissected free and the total proteins were extracted. Western blotting was performed to confirm the protein expression of 3 NOS isoforms and GC.
  
  
  RESULTS
  Expression of 3 NOS isoforms and GC were observed in the ciliary epithelium, ciliary muscle, trabecular meshwork and the endothelium of the Schlemm's canal. Immunoreactivity of nNOS was detected mainly along the apical cytoplasmic junction of the non-pigmented epithelium (NPE) and pigmented epithelial (PE) cells. Protein expressions of 3 NOS isoforms and GC were confirmed in isolated human ciliary body by Western blotting.
  
  
  CONCLUSIONS
  The expression of NOS isoforms and GC in human ciliary body suggest the possible involvement of NO and cyclic guanosine monophosphate (cyclic GMP, cGMP) signaling pathway in the ciliary body, and may play a role in both processes of aqueous humor formation and drainage.
authors.affiliation: Tianjin Eye Hospital, Tianjin Medical University, Tianjin 300020, China. wubasel@hotmail.com
authors.forename: Ren-Yi
authors.initials: RY
authors.lastname: Wu
authors.forename: Ning
authors.initials: N
authors.lastname: Ma
mesh_terms: D002924:Ciliary Body / Q000201:enzymology*; D006162:Guanylate Cyclase / Q000378:metabolism*; D006801:Humans; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D014129:Trabecular Meshwork / Q000201:enzymology*
chemical_list: D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase