Abstract
The effect of i.v. (67 µg/kg) and intracameral (10-4 M) ouabain and acetazolamide on aqueous humor (AH) formation rate, transport of Na22 and Cl36 from plasma to AH and outflow facility was studied in anesthetized cats. Ouabain produced a significant reduction in AH formation rate and transport of Na22 and Cl36 from plasma to AH, without any significant change in outflow facility. Lower doses of ouabain did not produce any significant change in these parameters. Doses of 10 mg/kg i.v. or 10-4 M intracameral acetazolamide produced a significant reduction in AH formation rate and transport of Na22 and Cl36 from plasma to AH, with a slight decrease in outflow facility. Lower i.v. doses had a smaller but significant inhibitory effect on AH formation rate and transport of Na+ and Cl- without any significant effect on outflow facility. Doses less than 1 mg/kg i.v. or 10-6 M intracameral acetazolamide did not produce any significant effect in any of the measured parameters. It is concluded that the inhibitory effect of ouabain on AH formation rate and ion transport from plasma to AH is probably mediated through inhibition of active Na+- and/or Cl--concentrating mechanism in the eye. The inhibitory effect of acetazolamide on AH formation rate and Na+ transport may be partly due to a reduction in HCO3- accumulation caused by the inhibition of carbonic anhydrase in the ciliary body. It may be due partly to its effect on Cl- secretion. However, it is not certain whether the effect of acetazolamide on Cl- secretion is due to the inhibition of carbonic anhydrase or due to its effect on some other receptor in the eye.
Footnotes
- Received May 15, 1970.
- Accepted July 14, 1970.
- © 1970 by The Williams & Wilkins Co.
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