Topical forskolin (colforsin) and aqueous flow in humans
R. F. Brubaker, K. H. Carlson, L. J. Kullerstrand and J. W. McLaren
A 1% forskolin (nonproprietary name, colforsin) suspension was instilled in
one eye each of 15 normal human subjects in a single-dose experiment under
the following three conditions: during the day, during the night while
asleep, and following pretreatment with timolol maleate. The rate of flow
was 2.6 +/- 0.13 microL/min (mean +/- SE) in the afternoon in both the
treated and the untreated eyes. During sleep at night the flow was lower
than in the afternoon in both the placebo-treated eye, 1.5 +/- 0.09
microL/min, and the forskolin-treated eye, 1.3 +/- 0.09 microL/min. Timolol
pretreatment reduced the flow to 1.6 +/- 0.08 microL/min in the
placebo-treated eye and 1.6 +/- 0.10 microL/min in the forskolin-treated
eye. No statistically significant effects of forskolin on flow were
observed under any of the conditions. Forskolin caused transient hyperemia
in all subjects. The experiment confirmed previous reports of differences
in the rate of aqueous flow at different times of day and the effect of the
beta-adrenergic blocker timolol on the rate of aqueous humor flow.
