Figure 2.

Effects of extracellular calcium and flufenamic acid. a, Induction of persistent firing in carbachol plus synaptic blockers (CCh + SB; 10 μm carbachol, 2 mm kynurenic acid, and 100 μm picrotoxin). b, Persistent firing was not induced when a calcium-free version of the same solution was used in the same cell as in a. c, Induction of persistent firing in carbachol plus synaptic blockers (CCh + SB; 10 μm carbachol, 2 mm kynurenic acid, and 100 μm picrotoxin). d, Persistent firing was blocked when the same solution was used with addition of flufenamic acid (100 μm) in the same cell as in c. Amplitudes of current injections were 50 pA for a and b, and 150 pA for c and d. e, Frequency of persistent firing. f, Poststimulus potential. Flufen, Flufenamic acid.