Bupivacaine and lidocaine blockade of calcium-mediated slow action potentials in guinea pig ventricular muscle

J Pharmacol Exp Ther. 1987 Sep;242(3):1001-5.

Abstract

The effects of bupivacaine and lidocaine on the slow-rising action potentials, induced by superfusion with high-K+ (26 mM) Tyrode's solution with 10(-6) M isoproterenol, were studied in guinea pig ventricular muscle. The concentrations of bupivacaine or lidocaine necessary to result in a 50% depression of the maximum upstroke velocity were about 10(-5) and 10(-4) M, respectively. The concentrations necessary to completely block the slow action potentials were about 10(-4) M for bupivacaine and 5 X 10(-4) M for lidocaine. The relative potencies of lidocaine to bupivacaine in abolishment of the slow action potentials are in the ratio of 1:5. These results suggest that local anesthetics do affect the slow Ca++ channel of ventricular muscle.

MeSH terms

  • Action Potentials / drug effects
  • Animals
  • Bupivacaine / pharmacology*
  • Calcium / metabolism*
  • Female
  • Guinea Pigs
  • In Vitro Techniques
  • Ion Channels / drug effects*
  • Lidocaine / pharmacology*
  • Male
  • Papillary Muscles / drug effects
  • Papillary Muscles / physiology*
  • Sodium / metabolism

Substances

  • Ion Channels
  • Lidocaine
  • Sodium
  • Calcium
  • Bupivacaine