Figure 1.

Representative whole-cell recordings of CAEC from rat carotid artery (CA) and inhibition by selective IK1 and SK3 blockers. For K_Ca-activation CAEC were dialyzed with a 140 mM K⁺ pipette solution containing 3 μM [Ca²⁺]_free. Bathing solution contained 4.5 mM K⁺. Inhibition of Ca²⁺-activated K⁺-currents by TRAM-34 (A) and TRAM-39 (B) at indicated concentrations. TRAM-34- and TRAM-39-insensitive Ca²⁺-activated K⁺-currents were inhibited by APA. (C) Concentration-dependent blockade of apamin-resistant K_Ca-currents by TRAM-34 (n=4–6) and TRAM-39 (n=4–6) determined at membrane potential of 0 mV and in the presence of 200 nM apamin. Data points were fitted to the Boltzmann equation. Values are given as mean±s.e.mean. (D-F) Representative current-clamp recordings of endothelial membrane potentials and ACh-induced hyperpolarization and its inhibition by APA (200 nM) and TRAM-34 (1 μM). (G) Representative ‘multiplex' RT–PCR analysis of single EC from rat CA in situ. Ethidium bromide-stained gels of RT–PCR products of eNOS and the K_Ca-genes, rSK3 and rIK1 from 2 EC, one medium sample as negative control and one non-template control (H₂0); right lane, molecular weight marker.