Double-gating mechanism and diversity of an adenosine triphosphate (ATP)-sensitive K(+) channel in neurons acutely dissociated from rat neocortex.
Classically, ion channels are classified into 2 groups: chemical-sensitive (ligand-gated) and voltage sensitive channels. Single ATP-sensitive K(+) (K-ATP) channel currents were recorded in acutely dissociated rat neocortical neurons using patch clamp technique. A type of K-ATP channel has been found to be gated not only by intracellular ATP, but also by membrane potential (V(m)), and proved to be a novel mechanism underlying the gating of ion channels, namely bi-gating mechanism. The results also show that the K-ATP channels possess heterogeneity and diversity. These types of K-ATP channels have been identified in 40.12% of all patches, which are different in activation-threshold and voltage-sensitivity. The present experiment studied the type-3 K-ATP channel with a unitary conductance of about 80 pS in detail (n = 15). Taking account of all the available data, a variety of K-ATP channels are suggested to exist in body, and one type of them is bi-gated by both chemical substances and membrane potentials. This property of the K-ATP channels may be related to their pathophysiological function.
Tong
Z
Z
Department of Physiology, First Military Medical University, 510515, Guangzhou, China.
Tang
X
X
Yang
W
W