INTRAOCULAR-PRESSURE AND AQUEOUS FLOW ARE DECREASED BY CHOLERA-TOXIN

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  • 1 January 1981
    • journal article
    • research article
    • Vol. 20  (3) , 371-381
Abstract
Delivery of 2.1 .mu.g of cholera toxin, a specific, irreversible activator of adenylate cyclase, in rabbits via the blood lowered IOP [intraocular pressure] from 17.4-11.2 mm Hg in 8 1/2 h, decreased net aqueous flow by about 50% in 8 h and doubled blood flow to the anterior uvea at 8-13 h. Intravitreal injection of 0.26 .mu.g of cholera toxin lowered IOP from 15.0-9.6 mm Hg. Heat-inactivated toxin had no effect on IOP. The toxin activates adenylate cyclase from ciliary processes 2.2-fold and stimulates cAMP production by ciliary processes 7.4 times. Absence of aqueous flare, normal protein concentrations in the aqueous and histologic examination all confirmed the functional and structural integrity of the blood-aqueous barrier after cholera toxin infusion. Ciliary process adenylate cyclase apparently play an important role in regulation of aqueous flow and maintenance of IOP.