Figure 6. ACh-hyperpolarization in smooth muscle cells was partially blocked by Ba²⁺ and completely blocked by additional 18βGRA.

Cells are from tracer-identified SMC or EC. Note that Ba²⁺ (100 μm) strongly blocked 10 mm K⁺-induced hyperpolarization in both types of cells (A–D and F), but only partially suppressed the ACh-hyperpolarization in SMCs (A, B and E) and had no significant inhibition on the ACh-hyperpolarization in ECs (C and D). Addition of ouabain further reduced the ACh-hyperpolarization in the SMC (A) but had little effect on the amplitude of ACh-hyperpolarization in the EC (C). ACh-hyperpolarization was almost completely blocked by a combination of Ba²⁺ and a gap junction blocker 18βGRA in the SMC (B) but not in the EC (D). Gaps in traces (A, C and D, 60 s to 32 min) were omitted segments of continuous recording for clarity.