SMAKing Ca~(2+) sparks in arterial myocytes

摘要

In the current issue of The Journal of Physiology, Essin et al. (2007) examined the relationship between Cavl.2 L-type Ca~(2+) channel function and Ca~(2+) spark activity in arterial myocytes. To do this, they took advantage of the SMAKO mouse (Moosmang et al. 2003) - a conditional, vascular smooth muscle-specific Cavl.2 knock-out mouse. Using SMAKO mice they provide what represents the strongest, most direct demonstration that, in arterial myocytes, local Ca~(2+) signalling between Cavl.2 channels and ryanodine receptors (RyRs) is not required for the activation of Ca~(2+) sparks. Rather, Cavl.2 activity influences Ca~(2+) spark activity in a subtler, indirect way by controlling sarcoplasmic reticulum (SR) Ca~(2+) load. The functional implications of these findings are discussed below