Fig. 4.

Sumatriptan increases the concentration of intracellular calcium in trigeminal neurons. A, Intracellular calcium concentrations, [Ca²⁺]_i, from day 4 cultures were measured using fura-2 and a microscopic digital imaging system. The pseudo-color scale indicates the [Ca²⁺]_i. Basal levels are in a single neuron with a neurite. B, The same cell 6 min after addition of 10 μm sumatriptan. C, The same cell after 12 min. D, A graphic representation of the change in [Ca²⁺]_i as a function of time after sumatriptan treatment of a representative cell (same cell as above). For comparison, a trace of a different cell treated with only KCl (60 mm) is superimposed.