[The effect of local anesthetics on the isolated human right atrial appendages--Part 2: Bupivacaine is different from lidocaine concerning the mechanism of inhibition of contractility].
With regard to the inhibition of contractility, dose-response curves of ryanodine and nickel were produced, and in these curves ID50 values were 10(-6) M and 2 x 10(-3) M, respectively. ID50 of bupivacaine was similar to ryanodine's and that of lidocaine was between ryanodine and nickel. On the post-rest potentiation (PRP) elicited after 2 s of rest following a train of stimulation at 3 Hz, ryanodine and bupivacaine had similar depressing effects, but lidocaine depressed it moderately and nickel showed no effect. These results suggest that bupivacaine could cause a direct inhibitory effect on sarcoplasmic reticulum (SR) function like ryanodine, but lidocaine could cause mainly a reduction in trans-sarcolemmal Ca influx and induce a slight inhibitory effect on SR function.
Minakuchi
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C
Department of Anesthesiology, School of Medicine, Juntendo University, Tokyo.
Itoh
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H
D002045:Bupivacaine / Q000494:pharmacology*; D003864:Depression, Chemical; D006801:Humans; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D009532:Nickel / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects
D012433:Ryanodine; D009532:Nickel; D008012:Lidocaine; D002045:Bupivacaine