Physiological Roles of Inward-Rectifying K+ Channels.

Physiological Roles of Inward-Rectifying K+ Channels.

Inwardly rectifying potassium channels: their structure, function, and physiological roles.

Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by ...

Inward-rectifying K+ channels in guard cells provide a mechanism for low-affinity K+ uptake.

The molecular mechanisms by which higher plant cells take up K+ across the plasma membrane (plasmalemma) remain unknown. Physiological transport studies in a large number of higher plant cell types, including guard cells, have suggested that at least two distinct types of K(+)-uptake mechanisms exist, permitting low-affinity and high-affinity K+ accumulation, respectively. Recent patch clamp st...

Inward Rectifying K Channels in the Plasma Membrane of Arabidopsis thaliana.

Ion channels in the plasma membrane of protoplasts isolated from cultured cells of Arabidopsis thaliana were studied by means of the patch-clamp technique applied in the whole-cell configuration. In some protoplasts, depolarizing pulses and, in other protoplasts, hyperpolarizing pulses elicited time-dependent currents; both kinds of current were only rarely observed in the same protoplast. The ...

Block of inward rectifying K+ channels (KIR) inhibits bradykinin-induced vasodilatation in human forearm resistance vasculature.

OBJECTIVE To investigate the possible involvement of inward rectifying K(+) channels (K(IR)) in the response of human resistance vessels to bradykinin in vivo. METHODS AND RESULTS Drugs were administered via the brachial artery in healthy male volunteers and forearm blood flow was measured by venous occlusion plethysmography. Inhibition of K(IR) by barium chloride (4 micromol min(-1)) alone o...