Vasorelaxing effect of the potassium (K+)-channel opener pinacidil in isolated porcine ciliary arteries.
OBJECTIVE
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 microM), and then exposed, in a cumulative manner, to increasing concentrations of pinacidil (1 nM-100 microM). Relaxations have been expressed in percent of the maximal contraction evoked by U 46619 (0.1 microM).


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 microM: 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.
Morf
T
T
Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic Basel, Mittlere Strasse 91, PO Box, CH-4012 Basel.
Zhu
P
P
Flammer
J
J
Haefliger
I O
IO
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D019842:Ciliary Arteries / Q000187:drug effects*; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D020110:Pinacidil / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects*; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D015221:Potassium Channels; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D020110:Pinacidil