The effects of caffeine on ATP-sensitive K(+) channels in smooth muscle cells from pig urethra.

ABSTRACT: The effects of caffeine on both levcromakalim-induced macroscopic and unitary currents in pig proximal urethra were investigated by the use of patch-clamp techniques (conventional whole-cell configuration and cell-attached configuration). The effects of caffeine were also examined on currents in inside-out patches of COS7 cells expressing carboxy terminus truncated inwardly rectifying K(+) channel (Kir6.2) subunits (i.e. Kir6.2DeltaC36) which form ATP-sensitive K(+) channels (K(ATP) channels). In conventional whole-cell configuration, the levcromakalim (100 microM)-induced inward current (symmetrical 140 mM K(+) conditions) was inhibited by caffeine (> or =1 mM) at a holding potential of -50 mV. In contrast, ryanodine (10 microM) caused no significant inhibitory effect on the gradual decay

SUBMITTER: Teramoto N 

PROVIDER: S-EPMC1572345 | biostudies-literature | 2000 Oct

REPOSITORIES: biostudies-literature