Blockage of axonal transport in optic nerve induced by elevation of intraocular pressure. Effect of arterial hypertension induced by angiotensin I.

Previous studies have shown that elevation of intraocular pressure blocks rapid axonal transport at the lamina cribrosa of the optic nerve. In this study, IOP-induced blockage of axonal transport was greater in cats with elevation of BP induced by angiotensin I than in control animals with normal BP. The fact that cardiovascular factors influenced IOP-induced blockage of axonal transport suggests that it is due to ischemia; if the blockage were a direct mechanical effect of the IOP on the axons, it should be unaffected by BP. The data also suggest that the vasoconstrictive properties of angiotensin I reduced the ability of the vasculature of the optic nerve head to autoregulate when challenged by elevation of IOP.