Purpose: To determine the effect of domestic Forskolin on lowering of intraocular pressure (IOP) in rabbits.
Methods: Measure the normal IOP and ocular hypertension by water load in rabbits using Perkins tonometer. Measure the adenylate cyclase (AC) activity by Ho & Sutherland's method.
Results: The results show that Forskolin significantly lowered the normal IOP of rabbits and blocked the ocular hypertension induced by water load in rabbits (P < 0.01). The maximum decrease value of 2%, 1% and 0.5% of the Forskolin was 0.59, 0.36 and 0.19 kPa (1kPa = 7.5 mmHg), which showed the noticeable dose-effect relationship. Topical ocular application of Forskolin lowered IOP in half an hour, reached to a peak in 2-3 hours and remained significantly for 10 hours. The pupillary diameter did not change when IOP was reduced. The Forskolin had potent stimulative properties to AC. The greater the ability of the Forskolin to stimulate AC, the stronger the effect of IOP lowering.
Conclusions: The Forskolin had the effect on lowering the IOP of rabbits. The mechanism of IOP reduction by Forskolin is related to its AC activation.