Inward rectification and vascular function: As it was in the beginning

摘要

Potassium channels are known to play an important role in the regulation of vascular tone through their ability to hyperpolarize smooth muscle cells and produce vasodilatation, primarily by causing the closure of voltage-dependent calcium channels. Of the four different classes of potassium channels found in blood vessels (ATP-sensitive potassium channels, inwardly rectifying potassium channels (Kir), voltage-activated potassium channels and calcium-activated potassium channels), Kir channels have been implicated in a range of vasomotor functions, from vasodilatation of cerebral, coronary and skeletal muscle vascular beds in response to local release of potassium ions (K+; for example, see Quayle etal. 1997; Armstrong et al. 2007) to augmentation and facilitation of the propagation of vasodilatory responses over distance along microcirculatory arterioles and feed arteries (Rivers et al. 2001; Goto et al. 2004; Jantzi et al. 2006). Finally, down-regulation or inactivation of these channels is increasingly seen as instrumental in the increased excitability of vascular smooth muscle found in pathological conditions such as hypertension, hypercholesterolaemia and diabetes (Chrissobolis & Sobey, 2003; Jackson, 2006; Matsushita & Puro, 2006).