Artikel
Effects of Acetazolamide on the tone of the posterior ciliary arteries
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Autoren
Veröffentlicht: | 22. September 2004 |
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Gliederung
Text
Objective
Acetazolamide plays an important role as an inhibitor of the carbonic anhydrase as drug for lowering of intraocular pressure. It is reported that acetazolamide has a positive effect on peripheral blood supply, but in case of the eye there are no definite data. Hemodynamic effects of acetazolmide are attributed to a direct interaction with smooth vascular muscle. The aim of the current study is to examine effects of acetazolamide on the tone of the posterior ciliary arteries.
Methods
Rings of the posterior ciliary arteries were dissected from pigs eyes, which were obtained from a slaughterhouse. In a setup for measurement of muscle force the basal tone of the vessels and the maximum force after potassium-depolarisation where measured in a physiological environment (pH 7.4, 37°C, Krebs-Henseleit-Buffer) without and with acetazolamide.
Results
Basal tone was not changed significantly neither by 10-6 M acetazolamide (-0,4±0,14 mN vs. -0,54±0,36 mN, p=0,64) nor 10-5 M acetazolamide (-0,31±0,29 mN vs. -0,54±0,36 mN, p=0,74) compared to solvent. Force of potassium-induced depolarisations increased in tendency but statistically not significant in presence of 10-6 M acetazolamide (9,2±3,3 mN vs. 9,7±3,4 mN; n=7; p=0,07). At 10-5 M there was no change in the tension of the depolarized muscle ring (13,7±1,7 mN vs. 13,1±2,2 mN; n=4; p=0,53). The solvent of acetazolamide also had no effect on the muscle tone.
Conclusions
In the tested therapeutic relevant concentrations, acetazolamide had no relaxing effect on the tone of isolated posterior ciliary arteries of the pig, but at lower concentration there was a tendency for vasoconstriction. For other organ systems it is reported that acetazolamide improves blood flow by relaxing of the vasculature. This effect cannot be evoked in our system. Thus following our data we do not expect positive hemodynamic effects of acetazolamide at the eye.