Published in:
01-04-2015 | Original Article
Direct effects of Rho-kinase inhibitor on pial microvessels in rabbits
Published in: Journal of Anesthesia | Issue 2/2015
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Purpose
Rho-kinase inhibitor is widely used for prevention of cerebral vascular spasm. However, the cerebral pial vascular action of Rho-kinase inhibitor has not been investigated. We therefore evaluated the direct effects of Y-27632, a Rho-kinase inhibitor, on pial microvessels.
Method
Experiments were performed on anesthetized rabbits. A closed cranial window was used to visualize the pial microcirculation. After baseline hemodynamic and pial vascular measurements, the cranial window was superfused with four increasing concentrations of Y-27632 (10−9, 10−7, 10−6, 10−5 mol l−1; n = 7) dissolved in artificial cerebrospinal fluid for 7 min each. We measured the diameters of pial vessels, mean arterial pressure (MAP), heart rate (HR), and rectal temperature at 7 min after application of each Y-27632 concentration.
Results
MAP, HR, rectal temperature, arterial pH, PaCO2, PaO2, and plasma Na+, K+ and glucose concentrations did not change significantly during the experimental period. Y-27632 at 10−9 to 10−7 mol l−1 did not produce any significant change in pial arterioles. Topical application of Y-27632 at 10−6 and 10−5 mol l−1 produced pial large (8.4 ± 5.7 and 19.8 ± 12.7 %) and small (10.1 ± 8.5 and 18.1 ± 12.3 %) arterioles dilation. However, Y-27632 did not produce any change in pial large and small venules.
Conclusion
We evaluated the direct effects of Y-27632 on pial microvessels. Y-27632 dilates only pial arterioles in a concentration-dependent manner, and most at a concentration of 10−5 mol l−1. Y-27632 is a potent cerebral pial arteriolar dilator but is not a venular dilator.