Researchers infused Wistar rats with RS(±)-bupivacaine and S(−)-bupivacaine and tested cardiac electrical activity, cardiac muscle contraction and Ca2+ regulation. They found that the lethal dose of bupivacaine and strength of muscle twitches were higher in 2-week-old rats compared to 16-week-old rats. In addition, 2-week-old rats had a higher increase in Ca2+ release from the sarcoplasmic reticulum preactivated with caffeine than did their older counterparts.
The authors suggest that different mechanisms for intracellular SR Ca2+ regulation in younger rats may partially account for their decreased susceptibility to cardiodepression from bupivacaine.
Read the Anesthesia & Analgesia abstract on bupivacaine-induced cardiotoxicity at different ages.
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