Effect of intracellular injection of La3+ and Mn2+ on electrical coupling of heart cells.

The effect of intracellular injection of La3+ and Mn2+ on the electrical coupling of canine Purkinje cells investigated. It was found that La3+ causes cell decoupling in about 100 sec, increased the input resistance of the injected cell too. Mn2+ injection reduced drastically the coupling coefficient but did not abolish cell communication. Intracellular injection of La3+ or Mn2+ also caused shortening of the action potential and hyperpolarized the the heart cells. La3+ seems to be as effective as Ca or even stronger than Ca in suppressing intercellular communication in heart fibres.