In vivo Stimulus-Induced Vasodilation Occurs without IP3 Receptor Activation and May Precede Astrocytic Calcium Increase

Calcium-dependent release of vasoactive gliotransmitters is widely assumed to trigger vasodilation associated with rapid increases in neuronal activity. Inconsistent with this hypothesis, intact stimulus-induced vasodilation was observed in inositol 1,4,5-triphosphate (IP3) type-2 receptor (R2) knock-out (KO) mice, in which the primary mechanism of astrocytic calcium increase—the release of calcium from intracellular stores following activation of an IP3-dependent pathway—is lacking. Further, our results in wild-type (WT) mice indicate that in vivo onset of astrocytic calcium increase in response to sensory stimulus could be considerably delayed relative to the simultaneously measured onset of arteriolar dilation. Delayed calcium increases in WT mice were observed in both astrocytic cell bodies and perivascular endfeet. Thus, astrocytes may not play a role in the initiation of blood flow response, at least not via calcium-dependent mechanisms. Moreover, an increase in astrocytic intracellular calcium was not required for normal vasodilation in the IP3R2-KO animals.

[1]  C. Stosiek,et al.  In vivo two-photon calcium imaging of neuronal networks , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[2]  R. Koehler,et al.  Interaction of Mechanisms Involving Epoxyeicosatrienoic Acids, Adenosine Receptors, and Metabotropic Glutamate Receptors in Neurovascular Coupling in Rat Whisker Barrel Cortex , 2008, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[3]  T. Takano,et al.  Astrocyte-mediated control of cerebral blood flow , 2006, Nature Neuroscience.

[4]  Nanhong Lou,et al.  General anesthesia selectively disrupts astrocyte calcium signaling in the awake mouse cortex , 2012, Proceedings of the National Academy of Sciences.

[5]  P. Magistretti,et al.  Astrocyte–neuron metabolic relationships: for better and for worse , 2011, Trends in Neurosciences.

[6]  V. Murthy,et al.  Coupling of Neural Activity to Blood Flow in Olfactory Glomeruli Is Mediated by Astrocytic Pathways , 2008, Neuron.

[7]  Eric Betzig,et al.  Adaptive optics via pupil segmentation for high-resolution imaging in biological tissues , 2010, Nature Methods.

[8]  T. Murphy,et al.  Rapid Astrocyte Calcium Signals Correlate with Neuronal Activity and Onset of the Hemodynamic Response In Vivo , 2007, The Journal of Neuroscience.

[9]  Eduardo D. Martín,et al.  Astrocytes Mediate In Vivo Cholinergic-Induced Synaptic Plasticity , 2012, PLoS biology.

[10]  Baljit S Khakh,et al.  Bulk Loading of Calcium Indicator Dyes to Study Astrocyte Physiology: Key Limitations and Improvements Using Morphological Maps , 2011, The Journal of Neuroscience.

[11]  Michael M. Halassa,et al.  Synaptic Islands Defined by the Territory of a Single Astrocyte , 2007, The Journal of Neuroscience.

[12]  F. Helmchen,et al.  In vivo calcium imaging of neural network function. , 2007, Physiology.

[13]  Kenneth D Harris,et al.  Towards reliable spike-train recordings from thousands of neurons with multielectrodes , 2012, Current Opinion in Neurobiology.

[14]  D. Kleinfeld,et al.  Stimulus-Induced Changes in Blood Flow and 2-Deoxyglucose Uptake Dissociate in Ipsilateral Somatosensory Cortex , 2008, The Journal of Neuroscience.

[15]  Phillip B. Jones,et al.  Age-dependent cerebrovascular dysfunction in a transgenic mouse model of cerebral amyloid angiopathy. , 2007, Brain : a journal of neurology.

[16]  A. Dale,et al.  Cortical depth-specific microvascular dilation underlies laminar differences in blood oxygenation level-dependent functional MRI signal , 2010, Proceedings of the National Academy of Sciences.

[17]  D. Tank,et al.  Imaging Large-Scale Neural Activity with Cellular Resolution in Awake, Mobile Mice , 2007, Neuron.

[18]  T. Takano,et al.  Astrocytic Ca2+ signaling evoked by sensory stimulation in vivo , 2006, Nature Neuroscience.

[19]  Rafael Yuste,et al.  Astrocytic regulation of cortical UP states , 2011, Proceedings of the National Academy of Sciences.

[20]  Sergey L. Gratiy,et al.  In Vivo Alterations in Calcium Buffering Capacity in Transgenic Mouse Model of Synucleinopathy , 2012, The Journal of Neuroscience.

[21]  F. Helmchen,et al.  Sulforhodamine 101 as a specific marker of astroglia in the neocortex in vivo , 2004, Nature Methods.

[22]  Pierre J Magistretti,et al.  Sweet Sixteen for ANLS , 2012, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[23]  M. Steriade.  Grouping of brain rhythms in corticothalamic systems , 2006, Neuroscience.

[24]  Takahiro Takano,et al.  Astrocytic calcium signaling: mechanism and implications for functional brain imaging. , 2009, Methods in molecular biology.

[25]  B. MacVicar,et al.  Calcium transients in astrocyte endfeet cause cerebrovascular constrictions , 2004, Nature.

[26]  Hajime Hirase,et al.  Astrocyte calcium signaling transforms cholinergic modulation to cortical plasticity in vivo , 2011, Neuroscience Research.

[27]  A. Dale,et al.  Coupling of the cortical hemodynamic response to cortical and thalamic neuronal activity. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[28]  T. H. Brown,et al.  Metabotropic glutamate receptor activation induces calcium waves within hippocampal dendrites. , 1994, Journal of neurophysiology.

[29]  G. Buzsáki.  Large-scale recording of neuronal ensembles , 2004, Nature Neuroscience.

[30]  D. Attwell,et al.  Glial and neuronal control of brain blood flow , 2022 .

[31]  R G Shulman,et al.  Energy on Demand , 1999, Science.

[32]  Egill Rostrup,et al.  Cerebral Blood Flow Response to Functional Activation , 2010, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[33]  Khaleel Bhaukaurally,et al.  Local Ca2+ detection and modulation of synaptic release by astrocytes , 2011, Nature Neuroscience.

[34]  A. Nimmerjahn.  Astrocytes going live: advances and challenges , 2009, The Journal of physiology.

[35]  T. Takano,et al.  Astrocytes Modulate Neural Network Activity by Ca2+-Dependent Uptake of Extracellular K+ , 2012, Science Signaling.

[36]  H. Berg,et al.  Supporting Online Material Materials and Methods Som Text Figs. S1 to S7 Tables S1 to S3 References Movies S1 to S6 Tuned Responses of Astrocytes and Their Influence on Hemodynamic Signals in the Visual Cortex , 2022 .

[37]  M. C. Angulo,et al.  Neuron-to-astrocyte signaling is central to the dynamic control of brain microcirculation , 2003, Nature Neuroscience.

[38]  Nathalie Rouach,et al.  Astroglial Metabolic Networks Sustain Hippocampal Synaptic Transmission , 2008, Science.

[39]  P. Kara,et al.  An artery-specific fluorescent dye for studying neurovascular coupling , 2012, Nature Methods.

[40]  B. Cauli,et al.  Revisiting the Role of Neurons in Neurovascular Coupling , 2010, Front. Neuroenerg..

[41]  Alfred Buck,et al.  Metabotropic glutamate receptor mGluR5 is not involved in the early hemodynamic response , 2011, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[42]  Eric A Newman,et al.  Glial Cells Dilate and Constrict Blood Vessels: A Mechanism of Neurovascular Coupling , 2006, The Journal of Neuroscience.

[43]  T. Takano,et al.  Signaling at the Gliovascular Interface , 2003, The Journal of Neuroscience.

[44]  G. Christianson,et al.  Mouse auditory cortex differs from visual and somatosensory cortices in the laminar distribution of cytochrome oxidase and acetylcholinesterase , 2009, Brain Research.

[45]  O. Garaschuk,et al.  Targeted bulk-loading of fluorescent indicators for two-photon brain imaging in vivo , 2006, Nature Protocols.

[46]  Fabio Benfenati,et al.  Integrated Brain Circuits: Neuron-Astrocyte Interaction in Sleep-Related Rhythmogenesis , 2010, TheScientificWorldJournal.

[47]  M. Chen,et al.  Glutamate-Dependent Neuroglial Calcium Signaling Differs Between Young and Adult Brain , 2013, Science.

[48]  D. Kleinfeld,et al.  Suppressed Neuronal Activity and Concurrent Arteriolar Vasoconstriction May Explain Negative Blood Oxygenation Level-Dependent Signal , 2007, The Journal of Neuroscience.

[49]  Todd A Fiacco,et al.  Astrocyte calcium elevations: Properties, propagation, and effects on brain signaling , 2006, Glia.

[50]  C. Iadecola,et al.  Glial regulation of the cerebral microvasculature , 2007, Nature Neuroscience.

[51]  J. Meldolesi,et al.  Astrocytes, from brain glue to communication elements: the revolution continues , 2005, Nature Reviews Neuroscience.

[52]  R. Koehler,et al.  Astrocytes and the regulation of cerebral blood flow , 2009, Trends in Neurosciences.

[53]  Klas H. Pettersen,et al.  Amplitude variability and extracellular low-pass filtering of neuronal spikes. , 2008, Biophysical journal.

[54]  B. Cauli,et al.  Pyramidal Neurons Are “Neurogenic Hubs” in the Neurovascular Coupling Response to Whisker Stimulation , 2011, The Journal of Neuroscience.

[55]  F. Helmchen,et al.  Simultaneous BOLD fMRI and fiber-optic calcium recording in rat neocortex , 2012, Nature Methods.

[56]  Baljit S Khakh,et al.  A genetically targeted optical sensor to monitor calcium signals in astrocyte processes , 2010, Nature Neuroscience.

[57]  D. Kleinfeld,et al.  Fluctuating and sensory-induced vasodynamics in rodent cortex extend arteriole capacity , 2011, Proceedings of the National Academy of Sciences.

[58]  A. Dale,et al.  Coupling of Total Hemoglobin Concentration, Oxygenation, and Neural Activity in Rat Somatosensory Cortex , 2003, Neuron.

[59]  C. Jahr,et al.  Synaptic Activation of Glutamate Transporters in Hippocampal Astrocytes , 1997, Neuron.

[60]  D. Kleinfeld,et al.  Fluctuations and stimulus-induced changes in blood flow observed in individual capillaries in layers 2 through 4 of rat neocortex. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[61]  Dennis A. Turner,et al.  Differences in O2 availability resolve the apparent discrepancies in metabolic intrinsic optical signals in vivo and in vitro , 2007, Trends in Neurosciences.

[62]  Baljit S Khakh,et al.  Monitoring astrocyte calcium microdomains with improved membrane targeted GCaMP reporters. , 2010, Neuron glia biology.

[63]  Anders M. Dale,et al.  A vascular anatomical network model of the spatio-temporal response to brain activation , 2008, NeuroImage.

[64]  S. Wang,et al.  Radially expanding transglial calcium waves in the intact cerebellum , 2009, Proceedings of the National Academy of Sciences.

[65]  A. Nimmerjahn,et al.  Motor Behavior Activates Bergmann Glial Networks , 2009, Neuron.

[66]  Grant R. Gordon,et al.  Brain metabolism dictates the polarity of astrocyte control over arterioles , 2008, Nature.

[67]  A. Zima,et al.  Endothelin-1–Induced Arrhythmogenic Ca2+ Signaling Is Abolished in Atrial Myocytes of Inositol-1,4,5-Trisphosphate(IP3)–Receptor Type 2–Deficient Mice , 2005, Circulation research.

[68]  Todd A Fiacco,et al.  What Is the Role of Astrocyte Calcium in Neurophysiology? , 2008, Neuron.

[69]  Jakub Otáhal,et al.  Gamma Oscillations and Spontaneous Network Activity in the Hippocampus Are Highly Sensitive to Decreases in pO2 and Concomitant Changes in Mitochondrial Redox State , 2008, The Journal of Neuroscience.

[70]  Todd A Fiacco,et al.  Loss of IP3 Receptor-Dependent Ca2+ Increases in Hippocampal Astrocytes Does Not Affect Baseline CA1 Pyramidal Neuron Synaptic Activity , 2008, The Journal of Neuroscience.

[71]  Venkatesh N. Murthy,et al.  Role of Astrocytes in Neurovascular Coupling , 2011, Neuron.