Astrocyte-mediated control of cerebral blood flow

@article{Takano2006AstrocytemediatedCO,
  title={Astrocyte-mediated control of cerebral blood flow},
  author={Takahiro Takano and G F Tian and Weiguo Peng and Nanhong Lou and Witold Libionka and Xiaoning Han and Maiken Nedergaard},
  journal={Nature Neuroscience},
  year={2006},
  volume={9},
  pages={260-267}
}
Local increase in blood flow during neural activity forms the basis for functional brain imaging, but its mechanism remains poorly defined. Here we show that cortical astrocytes in vivo possess a powerful mechanism for rapid vasodilation. We imaged the activity of astrocytes labeled with the calcium (Ca2+)-sensitive indicator rhod-2 in somatosensory cortex of adult mice. Photolysis of caged Ca2+ in astrocytic endfeet ensheathing the vessel wall was associated with an 18% increase in arterial… 
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  • J. Filosa, J. Iddings
  • Biology, Medicine
    American journal of physiology. Heart and circulatory physiology
  • 2013
TLDR
Evidence for the various signaling modalities by which astrocytic activation leads to vasodilation and vasoconstriction of parenchymal arterioles is discussed and the importance of the transient receptor potential channel of the vanilloid family (TRPV4) as a key molecular determinant in the regulation of vascular tone in cerebral arteriole is highlighted.
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It is demonstrated that hypercapnia (increased CO2) evokes increases in astrocyte calcium signaling, which in turn stimulates COX-1 activity and generates downstream PgE2 production, which is critically dependent on brain levels of the antioxidant glutathione.
Purinergic mechanisms in gliovascular coupling.
TLDR
Experimental model-specific variations in purinergic influences on gliovascular signaling mechanisms, focusing on the cerebral cortex are given consideration, and findings obtained using in vitro and multiple in vivo models are compared.
Beyond neurovascular coupling, role of astrocytes in the regulation of vascular tone
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Mechanisms implicating astrocytes in NVC-mediated vascular responses, limitations encountered as a result of the challenges in maintaining all the constituents of the neurovascular unit intact and deliberate current controversial findings disputing a main role for astracytes are discussed.
Astrocyte control of the cerebrovasculature
TLDR
The activation of Ca2+ activated K+ channels in astrocyte endfeet and the efflux of K+ has also been suggested to modify vascular tone by hyperpolarization and relaxation of smooth muscle cells (SMCs), indicating that more work is needed to clarify the contributions ofAstrocytes to vascular dynamics under different cellular conditions.
Astrocytic calcium signaling: the information currency coupling neuronal activity to the cerebral microcirculation.
TLDR
This review highlights recent evidence implicating astrocytes in the regulation of intracerebral arteriolar diameter, with particular emphasis on the putative signaling molecules and pathways proposed to exert changes on arteriolaar physiology.
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