DYNAMICS AND LOCATION OF AXONAL-TRANSPORT BLOCKADE BY ACUTE INTRAOCULAR-PRESSURE ELEVATION IN PRIMATE OPTIC-NERVE

Abstract

Axonal transport in primate [Aotus trivirgatus and Saimiri sciureus] optic nerve axons was studied by autoradiography, scintillation counting and EM under conditions of short-term intraocular pressure elevation. With elevation of intraocular pressure to 30 mm Hg below mean arterial blood pressure, blockage of transport was detected within 2 h by autoradiography and within 1 h by EM. The earliest buildup of radioactively labeled protein and ultrastructurally visible cellular organelles was within the scleral lamina cribrosa. The degree of blockade, judged by amount of label buildup, increased with time. Some transported material traversed the lamina cribrosa despite pressure elevation at the level tested. Reversal of transport blockade occurred rapidly after normalization of intraocular pressure.