The effects of topical and intravenous ropivacaine on canine pial microcirculation.

To assess the direct cerebrovascular effects of ropivacaine, we studied pharmacological responses to its topical and intravenous (IV) administration on vasomotor tone of pial vessels in in vivo experiments using a parietal cranial window in 24 dogs anesthetized with pentobarbital. We directly measured the diameters of pial arteries and veins after the administration of five different concentrations of ropivacaine solution (10(-7) to 10(-3) mol/L) randomly given into the window (n = 10). In six dogs, after pretreating the pial vessels with yohimbine (10(-5) mol/L), the inhibitory action of yohimbine was examined after the application of ropivacaine (10(-3) mol/L).