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Clin Cardiol J Volume 1 | Issue 1
December 04-05, 2017 Dallas, USA
International Conference on
Heart Congress, Vascular Biology and Surgeon’s Meeting
On the regulation of local cerebral blood flow by neurons and astrocytes
Adam Institoris*
and
Grant R Gordon
University of Calgary, Canada
N
eurovascular coupling requires intricate communication among neurons, astrocytes and vascular contractile
cells that make fine adjustments to microvascular diameter. To meet the energy requirements of the resting
and active brain, astrocytes and neurons must regulate microvascular diameter tonically, in a manner that is
independent of neural activity, as well as dynamically in response to rapid changes in neural activity. Surprisingly,
little is known about how the brain coordinates these distinct modes of blood flow control. We have discovered
a key role for resting astrocyte Ca2+ in the steady-state dilation of micro-vessels. Specifically, we show that
reducing basal Ca2+ in astrocyte ‘endfeet’, which are the specialized astrocytic compartments that directly appose
microvascular elements, causes a vasoconstriction, in the absence of neural influences. Furthermore, we find that
astrocytes are not necessary for vasodilations in response to brief, physiologically relevant increases in neural
activity. We provide evidence that preventing Ca2+ transients specifically in the astrocytes that surround a micro-
vessel, has no impact on activity-dependent vasodilations. These evoked increases in microvascular diameter are,
however, largely eliminated by synaptic AMPA receptor and cyclooxygenase-2 blockade. Furthermore, this type
of synaptically driven vasodilation occurs independent of vascular conduction, suggesting a local synaptic effect
on nearby microvasculature. Our data suggests that astrocytes and neurons act in parallel to regulate blood flow
on distinct timescales.
Biography
Adam Institoris is a research analyst, Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of
Calgary.
ainstito@ucalgary.ca