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Updated: Apr 8, 2026

Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography
Published on: September 22, 2011
Arteriole dilation to synaptic activation that is sub-threshold to astrocyte endfoot Ca2+ transients
Ádám Institoris1,2, David George Rosenegger1, Grant Robert Gordon1
1Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Abstract:
Ca(2+)-dependent pathways in neurons and astrocyte endfeet initiate changes in arteriole diameter to regulate local brain blood flow. Whether there exists a threshold of synaptic activity in which arteriole diameter is controlled independent of astrocyte endfeet Ca(2+) remains unclear. We used two-photon fluorescence microscopy to examine synaptically evoked synthetic or genetic Ca(2+) indicator signals around penetrating arterioles in acute slices of the rat neocortex. We discovered a threshold below which vasodilation occurred in the absence of endfeet Ca(2+) signals but with consistent neuronal Ca(2+) transients, suggesting endfoot Ca(2+) is not necessary for activity-dependent vasodilation under subtle degrees of brain activation.
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