title: 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.
authors.affiliation: Department of Anesthesiology, Asahi University, 1851 Hozumi, Gifu 5010296, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Mukozawa
authors.forename: Ko
authors.initials: K
authors.lastname: Takakura
authors.forename: Maki
authors.initials: M
authors.lastname: Mizogami