Related Experiment Video
Updated: Nov 22, 2025

Two-photon Imaging of Intracellular Ca2+ Handling and Nitric Oxide Production in Endothelial and Smooth Muscle Cells of an Isolated Rat Aorta
Published on: June 10, 2015
Nitric oxide displays a biphasic effect on calcium dynamics in microglia
Matthew J E Maksoud1, Vasiliki Tellios1, Yun-Yan Xiang2
1Graduate Program of Neuroscience, The University of Western Ontario, Canada; Robarts Research Institute, The University of Western Ontario, Canada.
Abstract:
Calcium is a critical secondary messenger in microglia. In response to inflammation, microglia mobilize intracellular calcium and increase the expression of inducible nitric oxide synthase (iNOS), which produces nitric oxide (NO). This study set to explore whether NO regulates intracellular calcium dynamics through transient receptor potential (TRP) channels in primary wildtype (WT) and iNOS knockout (iNOS-/-) microglia, and the BV2 microglial cell line using calcium imaging and voltage-clamp recordings. Our results demonstrated that application of the NO-donor SNAP induced a biphasic calcium response in naïve murine microglia. Specifically, phase I was characterized by a rapid decline in calcium influx that was attenuated by pretreatment of the store operated calcium channel (SOCC) inhibitor 2APB, while phase II presented as a slow calcium influx that was abolished by pretreatment with the TRP vanilloid type 2 (TRPV2) channel inhibitor tranilast. Importantly, in the presence of a protein kinase G (PKG) inhibitor, the SNAP-mediated calcium decline in phase I persisted while the calcium influx in phase II was abolished. Application of thapsigargin to activate SOCCs caused a calcium influx through a nonselective cation conductance in BV2 microglia, which was abruptly attenuated by SNAP. Importantly, iNOS-/- microglia displayed a significantly larger calcium influx though SOCCs while expressing less stromal interaction molecule 1, Orai1, and TRP canonical type 1 and 3 mRNA, when compared to WT microglia. Together, these results demonstrate that NO signaling restricts calcium influx through SOCCs independent of PKG signaling and increases calcium influx through TRPV2 channels in a PKG-dependent mechanism in microglia.
More Related Videos
09:07Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis
Published on: February 18, 2020
06:54Quantifying Spontaneous Ca2+ Fluxes and their Downstream Effects in Primary Mouse Midbrain Neurons
Published on: September 9, 2020
Related Concept Videos
Nitric Oxide Signaling Pathway
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Antihypertensive Drugs: Action of Calcium Channel Blockers