Department of Physiology & Pharmacology, Hotchkiss Brain and Libin Cardiovascular Research Institutes, University of Calgary, Calgary, AB, Canada.
Microcirculation. 2013 May;20(4):299-306. doi: 10.1111/micc.12038.
Cerebral blood flow is controlled by a network of resistance arteries that dilate and constrict to mechanical and chemical stimuli. Vasoactive stimuli influence arterial diameter through alterations in resting membrane potential and the influx of Ca²⁺ through voltage-gated Ca²⁺ channels. Historically, L-type Ca²⁺ channels were thought to be solely expressed in cerebral arterial smooth muscle. Recent studies have, however, challenged this perspective, by providing evidence of T-type Ca²⁺ channels in vascular tissues. This perspective piece will introduce T-type Ca²⁺ channels, their electrophysiological properties, and potential roles in arterial tone development. We begin with a brief overview of Ca²⁺ channels and a discussion of the approaches used to isolate this elusive conductance. We will then speculate on how the two T-type Ca²⁺ channels expressed in cerebral arterial smooth muscle might differentially influence arterial tone. This discovery of T-type Ca²⁺ channels alters our traditional understanding of Ca²⁺ dynamics in vascular tissue and fosters new avenues of research and insight into the basis of arterial tone development.
脑血流由阻力动脉的网络控制，阻力动脉通过扩张和收缩来对机械和化学刺激做出反应。血管活性刺激通过改变静息膜电位和电压门控 Ca²⁺通道内 Ca²⁺的流入来影响动脉直径。从历史上看，L 型 Ca²⁺通道被认为仅在脑动脉平滑肌中表达。然而，最近的研究通过提供血管组织中 T 型 Ca²⁺通道的证据，对这一观点提出了挑战。这篇观点文章将介绍 T 型 Ca²⁺通道、它们的电生理特性以及它们在动脉张力发展中的潜在作用。我们首先简要概述 Ca²⁺通道，并讨论用于分离这种难以捉摸的电导率的方法。然后，我们将推测在脑动脉平滑肌中表达的两种 T 型 Ca²⁺通道如何不同地影响动脉张力。对 T 型 Ca²⁺通道的这一发现改变了我们对血管组织中 Ca²⁺动力学的传统理解，并为研究和深入了解动脉张力发展的基础提供了新的途径。
