Interaction of muscle relaxants [vecuronium and pancuronium] and local anaesthetics [bupivacaine and xylocaine] at the neuromuscular junction: a quantitative experimental study

Local anesthetics produce neuromuscular block, ganglionic block, and anticholinergic activity. This action is a dose dependent through interference with prejunction release of acetylcholine, stabilize post-junctional membranes, and directly depress muscle fibers. This study was done experimentally on isolated rat phrenic-nerve diaphragm preparation to test the interaction between vecuronium and pancuronium with bupivacaine and xylocaine. Bupivacaine caused reduction of contraction height produced by vecuronium from 56 +/- 2.9% to 74.5 +/- 5.35% and that produced by pancuronium from 49.4 +/- 3.06% to 66.4 +/- 4.48%. Xylocaine reduced the contraction height induced by vecuronium to 90.65 +/- 5.95% and that induced by pancuronium to 90.65 +/- 4.15%. This effect was not antagonized by calcium gluconate. Reversal of muscle relaxation by neostigmine was not affected by the local anesthetics

Superoxide dismutase, calcium, copper, ceruloplasmine levels after single and repeated exposure to halothane or isoflurane in albino rats

This study was done on 72 albino rats from both sexes. They were divided into three equal groups according to the time of exposure to the oxygen [control], isoflurane or halothane. Time of exposure was single [1 hour] or 3 or 5 exposures with 5 days rest in between. Samples were taken after 24 hours after the last exposure. Serum calcium, copper ceruloplasmine levels were estimated. Superoxide dismutase enzyme activity was also determined and showed a significant drop in the enzyme activity after both isoflurane and halothane anesthesia. The results of this study explored the potential risk of free oxygen radicals on liver cells after exposure of the rats to isoflurane or halothane anesthesia