Fig. 6.

Effects of U-73122, chelerythrine and calphostin C on Rf-induced actions on pacemaker potentials in cultured ICC clusters from murine small intestine. (A) (a) U-73122 (5 μM) abolished the generation of pacemaker potentials and blocked Rf -induced depolarizations. (b) U-73343 (inactive analog of U-73122) did not alter pacemaker potentials induced by Rf. (c) 2-APB (IP₃ receptor inhibitor) abolished the generation of pacemaker potentials and blocked Rf-induced depolarizations. Responses to Rf are summarized in (d). The bars represent mean values ± S.E. The effects of U-73122 on Rf-induced pacemaker potentials were significantly different to those induced by Rf alone. (B) (a,b) Pacemaker potentials of ICCs exposed to Rf in the presence of chelerythrine (1 μM) or calphostin C (1 μM). Under these conditions, Rf-induced membrane depolarizations were unaltered. Responses to Rf in the presence of chelerythrine and calphostin C are summarized in (c). The bars represent mean values ± S.E. ^**Significantly different from untreated controls (p < 0.01).