Purpose  To investigate the expression and distribution of nitric oxide 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 blot was performed to confirmed 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 blot.
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) signalling pathway in the cialiary body, and may play a role in both processes of aqueous humor formation and drainage.