The Effect of Choloride Channel on Aqueous Humor Production

Regulating the cell volume is an important factorin secretory function of epithelial cells and regulatory volume decrease (RVD) phenomenon is involved in response to the changes of cell volume and osmolarity. RVD of epithelial cells reflects cellular release of K+ and C1- through channels and K+ and C1- channels were verified in the basal membrane of the non pigmented ciliary epithelial cells. Therefore, we attempted to observe the involvement of C1- channel in aqueous humor production by performing the fluorophotometry after administration of the DIDS(4.4-diisothiocyanatostilbene-2-2-disulfonic acid), the C1 channel blocker. Ten white New Zealand rabbits, 5 for tonometry and 5 for fluorophotometry, were used. One eye was injected 2x10-4M DIDS intravitreally using microsyringe and the other eye was injected normalsaline as a control in each rabbits. Tonometry was performed before the injection and every hour after dosing for 5 hours. Fluorophotometry was performed every 30 minutes for 3 hours starting 2 hours after injection. Wilcoxon`s signed rank test was used for statistical analysis. DIDS decreased intraocular pressure by 12.5%(P<0.05) and reduced aqueous humor flow rate by 28.5%(P0.05). In conclusion, it was observed.

Comparison of the inhibitional effects of MK 507 and Timolol on the aqueous humor production by returning time to baseline intrliocular pressure

There has been need of carbonic anhydrase inhibitor eyedrops which has no systemic side effects, but it has problem in transcorneal coefficiency. Recently developed MK 507 has modified the lipid permeability. We researched on the efficiencies of MK 507 and Timolol by measuring the returning time to baseline intraocular pressure using Honan balloon. Forty-five healthy volunteers were divided into 3 groups. Group 1 was administered placebo. Group 2 was administered 0.25% timolol, and group 3 was administered 2% MK 507. The IOP was measured with Goldmann applanation tonometer at 2 hours before Honan balloon pressure (30mmHg, 30 minutes) and every 5 minutes after the pressure was released until IOP returned to baseline IOP. The returing time to baseline IOP was 19.17 +/- 2.31 minutes in group 1, 37.17 +/- 5.03 minutes in group 2, 31.67 +/- 2.40 minutes in group 3 (P- value: 0.0001) (AVOVA). The result of this study suggests that measuring the returing time to baseline IOP using Honan balloon may be useful in determining the effects of MK 507 and Timolol, adrenergic beta-blocker.