Effect of latanoprost on regional blood flow and capillary permeability inthe monkey eye

Objective: To evaluate the effects of latanoprost on regional blood flow an d capillary permeability in the monkey eye. Methods: Anesthetized cynomolgus monkeys were unilaterally treated with a s ingle dose containing 6 mu g of latanoprost; or 10 mu g of PhXA34 (13,14-di hydro-15R, S-17-phcnyl-18,19,20-trinor-prostaglandin F-2 alpha [PGF(2 alpha )]-isopropyl ester), which contains about 50% latanoprost. Regional blood f low in the eye was measured with radioactively labeled microspheres; capill ary permeability was measured by determining the extravascular plasma-equiv alent albumin space using I-125-albumin, I-131-albumin, and Cr-51-labeled e rythrocytes. Results: Latanoprost or PhXA34 had no or only a slight effect on the region al blood flow when measured 1, 2 1/2, 3, 4 1/2,and 6 hours after dose admin istration, with the exception of the anterior sclera, in which a moderate i ncrease in blood flow was detected. No effect on capillary permeability to albumin was detected when studied 30 minutes to 2 1/2 hours and 5 to 6 hour s after dose administration. Conclusion: Latanoprost, a selective prostaglandin F receptor agonist, exer ted no or only;light vascular effects for up to 6 hours after dose administ ration in the monkey eye, with the exception of the anterior sclera, in whi ch a moderate increase in blood flow was detected. Clinical Relevance: Naturally occurring prostaglandins may cause marked mic rocirculatory changes in the eye that could be of clinical concern. Latanop rost, a selective prostaglandin F receptor agonist, seems to be devoid of s uch effects.