Vasorelaxing effect of the potassium (K+)-channel opener pinacidil in isolated porcine ciliary arteries

Thomas Morf; Peili Zhu; Josef Flammer; Ivan O. Haefliger

doi:10.1055/s-2001-15894

Klinische Monatsblätter für Augenheilkunde, Inhaltsverzeichnis

Klin Monbl Augenheilkd 2001; 218(5): 338-340
DOI: 10.1055/s-2001-15894

EXPERIMENTELLE STUDIE

Georg Thieme Verlag Stuttgart · New York

Vasorelaxing effect of the potassium (K⁺)-channel opener pinacidil in isolated porcine ciliary arteries

Vasorelaxierende Eigenschaften von Pinacidil an isolierten Ziliararterien des SchweinesThomas Morf, Peili Zhu, Josef Flammer, Ivan O. Haefliger

Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic Basel, Mittlere Straße 91, PO Box, CH-4012 Basel

Abstract

Hintergrund Die vorliegende pharmakologische Studie wurde durchgeführt, um die vasorelaxierende Wirkung von Pinacidil (ein Kalium-Kanal-Öffner) an isolierten Ziliararterien des Schweines zu evaluieren.

Material und Methoden An Ziliararterien wurde mittels eines Myographsystems die isometrische Kraft bei kumulativ zunehmenden Konzentrationen (1 nM - 100 μM) von Pinacidil gemessen. Die Experimente wurden an durch Thromboxane A₂ Analogon U 46619 (0,1 μM) präkontrahierten Ziliararterien durchgeführt. Relaxationen wurden in Prozent einer durch U 46619 (0,1 μM) induzierten Kontraktion exprimiert.

Ergebnisse Pinacidil zeigte eine starke konzentrationsabhängige Abnahme der Kontraktionskraft in mit U 46619 präkontrahierten Ziliararterien (100 μM: 112 ± 2 %; n=7). Dieser Effekt war signifikant (p < 0,0001) verschieden von einer Kontrollgruppe (18 ± 6 %; n=6). Die Konzentration von Pinacidil, welche 50 % der maximalen Relaxation induzierte (pD₅₀), betrug 5,3 ± 0,1 (- log M).

Schlussfolgerung Pinacidil zeigt an isolierten Ziliararterien des Schweines starke vasorelaxierende Eigenschaften.

Abstract

Purpose The aim of this study was to investigate the vasorelaxing properties of pinacidil (a potassium-channel-opener) in isolated porcine ciliary arteries.

Methods Isometric contractions of isolated porcine ciliary arteries were measured with a myograph system. The vessels were first precontracted with the thromboxane A₂ analog U 46619 (0.1 μM), and then exposed, in a cumulative manner, to increasing concentrations of pinacidil (1 nM - 100 μM). Relaxations have been expressed in percent of the maximal contraction evoked by U 46619 (0.1 μM).

Results Pinacidil showed a pronounced concentration-dependent relaxing effect in isolated porcine ciliary arteries. The difference between pinacidil and time-control experiments was significant (100 μM: 112 ± 2 % vs. 18 ± 6 %, P < 0.0001). The half-maximal concentration (pD₅₀) value was 5.3 ± 0.1 (- log M).

Conclusions The present study indicates that pinacidil has marked vasorelaxing properties in isolated porcine ciliary arteries.

Schlüsselwörter

Normaldruckglaukom - vaskuläre Risikofaktoren - okulärer Blutfluss - Augeninnendruck - Glaukom-Therapie

Key words

normal tension glaucoma - vascular risk factor - ocular blood flow

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Referenzen

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