Skip to main content
. Author manuscript; available in PMC: 2014 May 1.
Published in final edited form as: Microcirculation. 2013 May;20(4):281–289. doi: 10.1111/micc.12046

Figure 6. Localized IP3 receptor-dependent SR Ca2+ release in vascular smooth muscle.

Figure 6

Ca2+-permeable inositol 1,4,5-trisphosphate receptors (IP3R) on the sarcoplasmic reticulum (SR) can produce non-propagating localized sites of elevated Ca2+. IP3 receptor Ca2+ release events near the vascular smooth muscle cell plasma membrane (VSMC PM) increase the activity of plasmalemmal ion channels such as transient receptor potential melastatin 4 (TRPM4). Ca2+ puff-dependent activation of TRPM4 channels generates depolarizing (+ Vm) inward currents (via Na+ influx) resulting in increased opening of voltage-dependent Cav1.2 L-type Ca2+ channels (L) and increased contraction.