Expression and function of KCNQ channels in CiliaryBody

BARILÁ, E.; GERMAN, O. L.; CARIGNANO, C.; SPITZMAUL, G.

Mar del plata, Buenos aires, Argentina.

Congreso; XXXII Congreso anual SAN 2017; 2017

SAN

The ciliary epithelium (CE) consist soft wolayers of secretory cells which are responsable for aqueous humor formation. One strategy inthetreatment of glaucoma is to reduce the inflow of aqueous humour, which relays on Cl-movement trough the epithelia. The rate of anion secretion depends on pumps, transporters, Na+ channels and still unknown K+ channels, which aid the out flow of Cl- by increasing its driving force. KCNQ channels( Kv7 ) are voltage gated K+ channels with 5 members in mammals (KCNQ1-5). Among some of their functions they participate in cell volume regulation and epithelial transport. We study the role of KCNQ channels in this process using KO mice for each channel. Whole-eye RT-PCR analysis showed expression of KCNQ 3 to-5 which is not present in their respective KO mice. Total homogenates of CE exhibited inmunoreactive bands for KCNQ4. Using KO controlled immunohistochemistry we founds pecific labeling for KCNQ4 on the membrane of the pigmented cells (PC) of the CE and absence of KCNQ 3 and-5. KCNQ4 was confined to the basolateral as well as the apical membrane of PCs, co-localizing with Connexin-43. Preliminary patch-clamp studies of non-pigmented cells lacking KCNQ4 expression, showed no changes in potassium currents. We conclude that KCNQ4 is expressed in the pigmented cells of the CE and could contribute to Cl-movement from the ciliary body stroma to the aqueous humor and may represent the molecular correlates of the K+ current.