Direct vasocontractile activities of bupivacaine enantiomers on the isolated rat thoracic aorta

Abstract

Background: In vitro studies with isolated arteries have shown direct vasoactivity of racemic bupivacaine. However, there is little information on the direct vasoactivities of bupivacaine enantiomers, S()- and R(+)-bupivacaine. Methods. We performed functional examinations using isolated intact thoracic aortic rings from male Wistar rats. Changes in ring tension produced by S(-)-, R(+)-, or racemic bupivacaine were measured in Krebs solution. Results. S(-)-bupivacaine produced the strongest contraction of the three agents. R(+)-bupivacaine showed limited vasoconstriction. The effects of racemic bupivacaine were located between these two. Conclusion. Each bupivacaine enantiomer showed specific vasocontractile activity, which affects the activity of racemic bupivacaine. Copyright © 2010 Mai Mukozawa et al.