Figure 1. The kinetics of [Ca²⁺]_i recovery following a glutamate challenge varies between cells and depends on the duration of glutamate exposure.

Cultured hippocampal neurones were stimulated with 100 μm glutamate (in a solution containing 0 Mg²⁺ and 10 μm glycine). A, representative trace showing the response of a neurone at 7 DIV to stimulation for 1 min. The decay phase showed biphasic kinetics of [Ca²⁺]_i recovery and was well fitted by a double exponential process with time constants τ_fast= 0.48 min and τ_slow= 14.47 min and relative amplitudes (A) of the fast and slow components A_fast= 0.92 and A_slow= 0.08. B, representative traces showing the responses of 4 individual neurones at 11 DIV (a and b) and 7 DIV (c and d) with different patterns of [Ca²⁺]_i recovery following glutamate stimulation for 10 min: a, ‘plateau response’; b and c, delayed and d, complete [Ca²⁺]_i recovery.