Figure 4. Involvement of aortic SMC Na_v channels in the contractile response to KCl.

The absence of endothelium was confirmed as described above. After washing and 15 min of incubation with prazosin (Pz; 10 µmol/L), suramin (300 µmol/L) and PPADS (30 µmol/L), increasing concentrations of KCl (1 to 100 mmol/L) were added in the absence or presence of TTX (1 µmol/L). (A) Representative recording of the isometric response. (B) Dose-responses to KCl in the absence (▒) or in the presence of 1 µmol/L TTX (•). Data are expressed as a percentage of the maximal KCl-induced contraction and were analyzed with a non-linear fit function to determine EC₅₀ values. Values represent means±s.e.m. of 5 animals, with experiments performed in quadruplicate.