Original Article

Effects of taurine on slow action potentials in papillary muscles of guinea pig

Authors: Ping LI, Yi KANG, Guo-xiang WANG


AIM: To examine the effects of taurine on the slow action potentials induced by KCl 24 mmol.L(-1) or tetrodotoxin 40 mumol.L(-1) in guinea pig papillary muscles.
METHODS: The transmembrane AP was recorded by a conventional glass microelectrode filled with KCl 3 mmol.L(-1). The muscles were exposed to high K(+)-Tyrode's solution or perfused with Tyrode's solution containing tetrodotoxin. Ouabain was added in order to induce oscillatory afterpotentials.
RESULTS: Taurine 20 mmol.L(-1) decreased the maximal upstroke velocity of slow action potential and prolonged the action potential duration at 50% of repolarization. The amplitude of slow action potential and the maximal upstroke velocity both increased by CaCl(2)3 mmol.L(-1) were antagonized by taurine. Taurine increased the concentration of ouabain for oscillatory afterpotential and prolonged the onset time of oscillatory afterpotential.
CONCLUSION: Taurine possesses a calcium antagonistic property.

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