Fig. 8.

Appearance of the slow signal in Mg²⁺-free bathing solution. The signals were obtained from an E14 preparation; in normal Ringer’s solution, no slow optical signal was observed (in the top recording), and in the Mg²⁺-free solution, small slow signals were detected (solid circles in the bottomrecording). These recordings were made by using the 128-element photodiode array.