Vasoactive actions of local anaesthetics on human isolated umbilical veins and arteries

Abstract

1 An in vitro study, using helical preparations of human umbilical arteries and veins obtained from healthy women at term pregnancy, was designed to determine: (a) whether three local anaesthetics commonly utilized in obstetric anaesthesia (bupivacaine, 2-chloroprocaine, and lignocaine) can induce contraction or relaxation of resting umbilical vessels; (b) whether these agents can induce contraction or relaxation of umbilical vessels which have been previously induced to contract by a known activator, potassium chloride (KCI); and (c) the relative potency of these agents as compared to KC1. 2 The results indicate that: (a) these local anaesthetics are vasoactive on human umbilical vascular smooth muscle; (b) bupivacaine induces contraction in over 90% of the resting vessels examined, while 2-chloroprocaine consistently causes relaxation and lignocaine causes a small degree of contraction in 40% of vessels examined; (c) bupivacaine causes further contraction (or potentiation) of KC1-contracted muscle in 50% of the vessels studied, while 2-chloroprocaine and lignocaine both induce relaxation of these contracted vessels.Introducion

Bupivacaine inhibits large conductance, voltage- and Ca2+- activated K+channels in human umbilical artery smooth muscle cells

“…In particular, bupivacaine produced contraction of rat muscle arterioles 7 and of isolated human umbilical artery (HUA) rings. 8,9 Additionally, Rossner et al 10 …”

In Vitro Vasoactive Effects Of Levobupivacaine And Ropivacaine On The Isolated Human Umbilical Artery And Vein.

“…Ancak paraservikal blok anestezisinde yüksek dozda anesteziğin uterin arterler etrafında birikmesi sonucu veya epidural anestezide lokal anesteziklerin dikkatsizlik ya da kaza sonucu yapılan intravasküler enjeksiyonları plazma konsantrasyonlarını yükseltebilir ve bu umblikal damar konsantrasyonlarını artırarak fetal yan etkilere neden olabilir (26). Ayrıca bozulmamış in vivo mikrosirkülasyon ilaçlara karşı deneylerde kullanılan büyük izole damarlara göre 10.000'den 100.000 kata kadar daha duyarlı olduğu gösterilmiştir (5).…”

“…İnsanlarda lokal anesteziklerin umblikal kordun düz kasına direkt etkisinin in vivo geniş olarak değerlendirilmesi zordur. İzole edilen damar şeritleri ile yapılan in vitro çalışmaların sonuçları in vivo ça-lışma yapılamayan alanlarda değerli kabul edilmektedir (5).…”

Vasorelaxant effect of mexiletine in mesenteric resistance arteries of rats

“…In contrast to mexiletine, there are many reports investigating vascular effects of lignocaine which possesses a chemical structure and pharmacological effects similar to those of mexiletine. The local anaesthetic causes relaxations (Altura & Altura, 1974;Wang & Jackson, 1988;Perlmutter, 1990) and, in some preparations, contractions (mainly in venous smooth muscles: Altura & Altura, 1974;Johns et al, 1985;Monuszko et at., .1989). Although inhibition of myosin light-chane kinase (Nosaka et al, 1989) and phospholipase A2 (Kunze et al, 1976;Willman & Hendrickson, 1978), and antagonistic effects on movement of calcium ions (Josephson & Sperelakis, 1976) in smooth muscle by lignocaine have been reported, local anaesthetics are generally believed to induce nonspecific inhibition of vascular tone (Altura & Altura, 1974).…”