Increase in aqueous humor production following D1 receptors activation by means of ibopamine

1573-2630

ibopamine ; dopamine ; glaucoma ; IOP

Springer Online Journal Archives 1860-2000

Medicine

Abstract Background: Topically administered 2% ibopamine (a dopaminergic agonist) induces a transitory ocular hypertension in 92% of patients with primary open-angle glaucoma and in 52% of patients with normal tension glaucoma. In normal eyes, ibopamine has no effect on IOP. Purpose: The aim of the present study was to verify, by means of fluorophotometric techniques, which hydrodynamic changes could be induced in normal and glaucomatous eyes, stimulating the Dl receptor with 2% ibopamine administered topically. In addiction, we wanted to evaluate if ibopamine could modify IOP before and after an experimentally induced outflow system impairment in rabbits. Methods: In study 1 we performed a measurement of aqueous humor flow in 6 healthy volunteers and in 6 glaucomatous patients, before and after 2% ibopamine administration. In study 2 the alteration of outflow pathways was induced by means of Laminaria Digitata in 10 rabbits. Results: After 2% ibopamine administration we found a significant increase in aqueous humor production, both in glaucomatous (P = 0.035) and normal eyes (P = 0.004). In rabbits, we found no significant change in IOP at basal conditions. After experimentally induced outflow system impairment by laminaria, we observed a marked increase in IOP (+ 13.5 mmHg SD 7.2; P 〈 = 0.001) following ibopamine administration. Conclusions: These experimental data have a diagnostic value in glaucoma, since they show how an intraocular hypertensive response due to ibopamine in normotensive eyes is a sign of initial outflow impairment. Moreover, the possibility to increase the aqueous humor production sets new trends in the treatment of post surgical ocular hypotony.

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