[Effect of topically applied iganidipine dihydrochloride, a novel Ca2+ antagonist, on optic nerve head circulation in rabbits].

PURPOSE

We studied the effect of topically applied iganidipine dihydrochloride, a novel water-soluble calcium channel blocker on the blood flow of optic nerve head (ONH), intraocular pressure, and blood pressure in rabbits.

METHODS

1. 0.1% iganidipine (20 microliters) was instilled into a normal eye. The change in blood flow in the ONH was measured using a hydrogen gas clearance flowmeter. 2. Iganidipine (0.0001%-0.1%) was instilled into a circulation-disordered eye before or after the intravitreal injection of endothelin-1, and change in the blood flow in the ONH was measured. 3. Changes in intraocular pressure and blood pressure after instillation of 0.1% iganidipine were measured. In all experiments, physiological saline was instilled in each contralateral eye as a control.

RESULTS

1. Instillation of iganidipine significantly increased the blood flow in the ONH by 40% at 45 minutes after instillation. 2. Pre-instillation of 0.01 and 0.1% iganidipine almost completely inhibited the decrease of blood flow in the ONH in the circulation-disordered model. The decrease of blood flow in the ONH was corrected with post-instillation of 0.1% iganidipine. These effects were continuous. 3. Instillation of 0.1% iganidipine did not change either intraocular pressure or blood pressure.

CONCLUSION

It was shown that instillation of iganidipine continuously increased and maintained the blood flow in the ONH in normal and circulation-disordered rabbit eye models.