advertisement
Abstract #6843 Published in IGR 4-1
Effect of Xalatan® and Cosopt® on the vascular tone of quiescent isolated pig ciliary arteries
Sherbini ME; Gekkieva M; Flammer J; Haefliger IOKlinische Monatsblätter für Augenheilkunde 2002; 219: 273-276
BACKGROUND: To investigate whether dilutions of the commercially available Xalatan® or Cosopt® induce vasoconstrictions in isolated quiescent porcine ciliary arteries. MATERIAL AND METHODS: Contractions measured with a myograph system (isometric force measurement) were expressed in percent of 100 mM potassium chloride (KCl)-induced contraction (mean ± standard error). In preliminary experiments, vessels were contracted with 100 mM KCl after previous exposures to different dilutions of Xalatan® (1/250 to 1/50) or Cosopt® (1/500 to 1/5). In a further series of experiments, vessels were exposed in a cumulative manner to different dilutions of Xalatan® or Cosopt® (1/50 000 to 1/166). RESULTS: Contractions induced by 100 mM KCl were not significantly affected by previous exposure to Xalatan® or Cosopt® at dilutions higher than 1/166 and 1/50, respectively. However, at the lower dilutions tested, 100 mM KCl-induced contractions were significantly (p < 0.001) and markedly inhibited (1/50 Xalatan®: 22.1 ± 2.8%; 1/5 Cosopt®: 24.8 ± 4.6%). In quiescent vessels, diluted (1/50 000 to 1/166) preparations of Xalatan® induced, in a dilution-dependent manner, statistically significant (p < 0.05) but, however very small (3.2 ± 1.0%) contractions in comparison to Cosopt® (- 0.6 ± 0.2%). CONCLUSIONS: Although on the basis of these in vitro experiments no clinical interpretation should be made, at very high dilutions that did not affect KCl-induced contractions, Xalatanm®, but not Cosopt®, had a very small vasoconstrictive effect in isolated quiescent porcine ciliary arteries. At low dilutions, responses to KCl were inhibited, possibly in relation to an unclear effect of the excipients of Xalatan® and Cosopt®.
Dr. M.E. Sherbini, Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic Basel, Switzerland
Classification:
11.4 Prostaglandins (Part of: 11 Medical treatment)
