Fig. 8. Effect of 5-hydroxytryptamine (5-HT) and ionomycin on [Ca²⁺]_i in scattered single ciliary cells. Scattered single ciliary cells were microinjected with fura-2 dextran and imaged once every 15 s. (A) A representative trace of an isolated tuft cell that did not respond to 100 µmol l^–1 5-HT and exhibited only a weak increase in [Ca²⁺]_i in response to 10 mmol l^–1 ionomycin. (B) A representative trace of an isolated tuft cell that displayed oscillations in [Ca²⁺]_i. Dotted lines represent the time when the specified treatments were initiated.