Fig. 4.

[K⁺]_i dependence of Ca²⁺ decay rate. A, Representative Ca²⁺ transients recorded with a K⁺ pipette (left) and with an NMG⁺ pipette (right). A Ca²⁺ transient recorded at 145 mm[Na⁺]_o (black traces) and that recorded at 20 mm[Na⁺]_o (gray traces; Na⁺ was replaced by Li⁺) were superimposed. B, Mean Ca²⁺ decay rate constants (γ_t=0) of Ca²⁺transients under conditions indicated below theabscissa. Subscripto andi represent external and internal major cations, respectively.