Fig. 3.

Effects of extracellular Ca²⁺ions on I_cold. A,I_cold was inactivated in Ca²⁺-containing bath solution (left). Duration of cooling was prolonged to clarify the inhibitory process, compared with Figure 2. In Ca²⁺-free solution,I_cold did not show inactivation (center). When bath solution was returned to Ca²⁺-containing solution, inactivation ofI_cold recovered (right). These responses were obtained in the same cell. B, When 10 mm BAPTA was included in a pipette,I_cold was not inactivated in Ca²⁺-containing bath solution.