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Abstract
The experiments were made to see whether a direct action of pilocarpine on the tissue close to Schlemm's canal is essential for a maximum reduction in outflow resistance. Anterior chambers of anesthetized vervet monkeys were connected to pressure transducers and reservoirs suspended on strain gauges. One eye ivas kept at a low pressure, the other 8 to 10 mm. Hg above the first. Fromthe difference in inflow rate and pressure, an apparent resistance can be calculated which would be correct if the eyes were identical. Intravenous injection of 1 mg. per kilogram pilocarpine HClcaused a precipitous resistance drop which toas virtually complete after 2 to 3 minutes and asdeepas after a supramaximum intracameral dose. The amount of pilocarpine in the anterior chamber after such an injection was measured with tritiated drug. It was quite ineffective. Thus in normal vervet eyes no direct action of pilocarpine on the tissue of the inner wall of Schlemm's canal is necessary for a very marked effect. This means that the total resistance of the fully utilized filtering tissue in a healthy vervet eye is either quite small or that the conductance of the tissue per unit area, its specific facility, is insensitive to pilocarpine.