///2009 Abstract Details
2009 Abstract Details2018-05-01T17:45:11+00:00

Effects of Bupivacaine and Magnesium on Serotonin-induced Vasocontraction in Isolated Human Umbilical Artery

Abstract Number: 156
Abstract Type: Original Research

Soochang Son MD1

Background: Serotonin is found in the blood of the umbilical cord at birth in concentrations sufficiently high to affect vascular tone. Serotonin has been suggested to be involved in the pathogenesis of preeclampsia(1). Magnesium sulfate( MgSO4) is used for the convulsion and hypertension in patients with preeclamptic toxemia(2). Bupivacaine is used in the epidural anesthesia for cesarean section. The goals of this study were to investigate the effects of magnesium and bupivacaine on serotonin-induced vasocontraction in human umbilical artery.

Methods: Following IRB approval and informed consent, experiment were performed on 52 human umbilical arteries. The rings were suspended in an organ bath to record isometric mechanical activity. we measured the concentration-contraction responses to bupivacaine, magnesium and serotonin, respectively. Vessels were pretreated with bupivacaine ( 10(-5) M) or magnesium ( 2 mM or 6 mM), and then serotonin ( 10(-9)M - 10(-6)M) was added cumulatively. Data analysis was assessed by unpaired t test, one-way ANOVA and Kruskal-Wallis test.

Results: Bupivacaine induced contraction of umbilical arterial rings, and showed maximal contraction (51.8 6.1%) at concentration of 43 μM. Magnesium induced relaxation of umbilical artery in a concentration dependent manner. Pretreatment with bupivacaine(10(-5)M) potentiated significantly the concentration response to serotonin(p<0.05). Pretreatment with MgSO4( 2 mM or 6 mM) significantly suppressed the contractile response to serotonin(p<0.05).

Conclusions: Bupivacaine, magnesium and serotonin are vasoactive on human umbilical arteries. Magnesium exert a strong relaxant effect on serotonin induced vasocontraction in human umbilical artery. Potentiation of serotonin induced vasoconstriction by bupivacaine may play a significant role in the reduction of umbilicoplacental blood flow.

Reference:

1. Acta Obstet Gynaecol 1990;42:1217-23.

2. Anesth Analg 1992;74:129-36.

SOAP 2009