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Direct Deviations in Astrocyte Free Ca2+ Concentration Control Multiple Arteriole Tone States

Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
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Academic Editor: Jessica Filosa
Received: 16 August 2021 / Revised: 15 September 2021 / Accepted: 2 October 2021 / Published: 14 October 2021
(This article belongs to the Special Issue Dynamic Vascular-Glial-Neuronal Interactions in Health and Disease)
Astrocytes elicit bidirectional control of microvascular diameter in acutely isolated brain slices through vasoconstriction and vasodilation pathways that can be differentially recruited via the free Ca2+ concentration in endfeet and/or the metabolic status of the tissue. However, the Ca2+-level hypothesis has not been tested using direct manipulation. To overcome this, we used Ca2+-clamp whole-cell patching of peri-arteriole astrocytes to change astrocyte-free Ca2+ to different concentrations and examined the vascular response. We discovered that clamping Ca2+ at the approximate resting value (100 nM) had no impact on arteriole diameter in a pre-constricted arteriole. However, a moderate elevation to 250 nM elicited sustained vasodilation that was blocked by the COX-1 antagonist SC-560 (500 nM). The vasodilation to 250 nM Ca2+ was sensitive to the metabolic state, as it converted to vasoconstriction when oxygen tension was dramatically elevated. In normal oxygen, clamping astrocyte Ca2+ well above the resting level (750 nM) produced sustained vasoconstriction, which converted to vasodilation in the 20-HETE blocker HET0016 (1 μM). This response was fully blocked by the addition of SC-560 (500 nM), showing that 20-HETE-induced vasoconstriction dominated the dilatory action of COX-1. These data demonstrate that direct changes in astrocyte free Ca2+ can control multiple arteriole tone states through different mediators. View Full-Text
Keywords: astrocyte; calcium; two-photon; patch clamp; arteriole; tone; steady-state astrocyte; calcium; two-photon; patch clamp; arteriole; tone; steady-state
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MDPI and ACS Style

Haidey, J.N.; Gordon, G.R. Direct Deviations in Astrocyte Free Ca2+ Concentration Control Multiple Arteriole Tone States. Neuroglia 2021, 2, 48-56. https://0-doi-org.brum.beds.ac.uk/10.3390/neuroglia2010006

AMA Style

Haidey JN, Gordon GR. Direct Deviations in Astrocyte Free Ca2+ Concentration Control Multiple Arteriole Tone States. Neuroglia. 2021; 2(1):48-56. https://0-doi-org.brum.beds.ac.uk/10.3390/neuroglia2010006

Chicago/Turabian Style

Haidey, Jordan N., and Grant R. Gordon 2021. "Direct Deviations in Astrocyte Free Ca2+ Concentration Control Multiple Arteriole Tone States" Neuroglia 2, no. 1: 48-56. https://0-doi-org.brum.beds.ac.uk/10.3390/neuroglia2010006

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