The Inhibition of Na, K-ATPase, and Mg-ATPase by Timolol Maleate in Cultured Non-Pigmented Epithelial Cells of the Ciliary Body
| Autor: | Doris H. Sorna, Brodrick Montgomery, David R. Whikehart |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
medicine.medical_specialty
ATPase Molecular Sequence Data Timolol Ciliary body Internal medicine medicine Animals Pharmacology (medical) Amino Acid Sequence Na+/K+-ATPase Ouabain Pigment Epithelium of Eye Cells Cultured Pharmacology Binding Sites biology Chemistry Cell Membrane Ciliary Body Biological activity Molecular biology Ophthalmology medicine.anatomical_structure Endocrinology Mechanism of action Enzyme inhibitor biology.protein Cattle Specific activity Ca(2+) Mg(2+)-ATPase Sodium-Potassium-Exchanging ATPase medicine.symptom medicine.drug |
| Zdroj: | Journal of Ocular Pharmacology and Therapeutics. 8:107-114 |
| ISSN: | 1557-7732 1080-7683 |
| DOI: | 10.1089/jop.1992.8.107 |
| Popis: | Bovine, non-pigmented, ciliary body epithelial cells were isolated and grown in culture to determine whether timolol maleate might affect the activity of their plasma membrane ATPases. The possible effects were tested in drug concentrations in a range of 5 x 10(-19) to 5 x 10(-5) M over an incubation period of 30 min at 37 degrees. Assays of specific activity showed that the drug significantly (p less than .001 for most concentrations) inhibited both Na,K-ATPase and Mg-ATPase. However, the inhibition was partially reversed in concentrations greater than 10(-6) M for Na,K-ATPase and 10(-5) M for Mg-ATPase. The latter enzyme also indicated a second partial reversal in activity at concentrations between 10(-12) and 10(-9) M. These reversals in activity suggest that more than one binding site is involved in the inhibition of both enzymes. Since Na,K-ATPase in non-pigmented, ciliary body cells is responsible for the generation of aqueous fluid and the intraocular pressure (IOP), this inhibition demonstrates a possible mechanism for the pharmacological action of timolol maleate in lowering IOP. |
| Databáze: | OpenAIRE |
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