Effect of serotonin, histamine and bradykinin on outflow facility following ciliary muscle retrodisplacement in the cynomolgus monkey.

Cynomolgus monkeys with surgically untouched, aniridic, or ciliary muscle disinserted eyes underwent two-level constant pressure perfusion of the anterior chamber to determine total outflow facility before and after intracameral infusion of bradykinin triacetate (0.1, 1, 10 micrograms), histamine dihydrochloride (1, 10, 100 micrograms), or serotonin creatinine sulfate (1, 10, 100 micrograms). Bradykinin had no effect on facility in non-disinserted eyes, but significantly decreased facility in disinserted eyes at all three dosages. Histamine tended to decrease facility in non-disinserted and disinserted eyes at all three dosages, although the decrease was not consistently significant statistically. Serotonin tended to decrease facility in non-disinserted eyes at dosages of 10 and 100 micrograms, although the effects were not statistically significant; 1 microgram had no effect. In disinserted eyes, 1 microgram significantly decreased facility, while the higher dosages had no (10 micrograms) or less (100 micrograms) effect. No simple mathematical/physiological description of the drug-induced facility decreases could be formulated. The facility decreases could be due to drug effects directly on the outflow pathways or secondary to blood-aqueous barrier breakdown.