Figure 4.

The effects of an external Ca²⁺-free solution or thapsigargin on the prostaglandin F_2α-induced response in pacemaker currents in cultured interstitial cells of Cajal from mouse small intestine. A: External Ca²⁺-free solution abolished the generation of pacemaker currents. Under these conditions, the prostaglandin F_2α (PGF_2α) (10 μmol/L)-induced tonic inward currents were blocked; C: Thapsigargin (5 μmol/L) abolished the generation of pacemaker currents. Thapsigargin also blocked the PGF_2α (10 μmol/L)-induced tonic inward currents. The dotted lines indicate the zero current levels. Responses to the PGF_2α in the external Ca²⁺-free solution and in the presence of thapsigargin are summarized in B and D. Vertical solid line scales denote amplitude of pacemaker current and horizontal solid line scales denote duration of recording (s) pacemaker current. The bars represent mean ± SE. ^bP < 0.01 vs the untreated control.