Effects of taurine on slow action potentials in papillary muscles of guinea pig
Li, P.; Kang, Y.; Wang, G.X.
Zhongguo Yao Li Xue Bao 16(3): 269-272
1995
ISSN/ISBN: 0253-9756 PMID: 7660826 Document Number: 444306
AIM: To examine the effects of taurine on the slow action potentials induced by KCl 24 mmol cntdot L-1 or tetrodotoxin 40 mu-mol cntdot L-1 in guinea pig papillary muscles. METHODS: The transmembrane AP was recorded by a conventional glass microelectrode filled with KCl 3 mmol cntdot 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 after potentials. RESULTS: Taurine 20 mmol cntdot 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 cntdot L-1 were antagonized by taurine. Taurine increased the concentration of ouabain for oscillatory afterpotential and prolonged the onset time of oscillatory after potential. CONCLUSION: Taurine possesses a calcium antagonistic property.