Anatomically “Calibrated” Isolated Respiratory Networks from Newborn Rodents

Ruangkittisakul, Araya; Panaitescu, Bogdan; Secchia, Lucia; Bobocea, Nicoleta; Kantor, Chase; Kuribayashi, Junya; Iizuka, Makito; Ballanyi, Klaus

doi:10.1007/978-1-62703-020-5_2

Cited by 19 publications

(4 citation statements)

References 92 publications

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“…This is in line with our findings on isolated preBötC and inspiratory motor networks which are more thoroughly (over)stimulated by theophylline than by caffeine upon spontaneous and drug-evoked depression of bursting (Ballanyi, 2004;Ruangkittisakul & Ballanyi, 2006;Ruangkittisakul et al, 2006Ruangkittisakul et al, , 2008Panaitescu et al, 2013). Seizure-like events were primarily evoked at low millimolar methylxanthine doses that are considerably higher than therapeutic levels, but correspond to those having a stimulatory effect on the isolated preBötC and, at the same time, cause seizure-like discharges in spinal motor networks Ruangkittisakul et al, , 2012Panaitescu et al, 2013). Seizure-like events were primarily evoked at low millimolar methylxanthine doses that are considerably higher than therapeutic levels, but correspond to those having a stimulatory effect on the isolated preBötC and, at the same time, cause seizure-like discharges in spinal motor networks Ruangkittisakul et al, , 2012Panaitescu et al, 2013).…”

Section: Relevance To Brain Circuit Development and Clinical Methylxasupporting

confidence: 91%

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Ruangkittisakul

Sharopov²,

Kantor

et al. 2015

Neuroscience

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Section: Relevance To Brain Circuit Development and Clinical Methylxasupporting

confidence: 91%

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Ruangkittisakul

Sharopov²,

Kantor

et al. 2015

Neuroscience

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“…Neurons and glia, stained in an area of 150–300 μm diameter, were imaged at 30–75 μm depths for several hours at scanning rates of 2.5 Hz that are sufficient to resolve peaks of inspiratory‐related [Ca 2+ ] i rises ( (Ruangkittisakul et al . , ).…”

Section: Methodsmentioning

confidence: 99%

“…The membrane-permeant Ca 2+ dye fluo-4-AM was pressure-injected (25-50 mmHg, 10 min) into the preBötC using a broken patch pipette filled with aCSF containing 0.5 mM Fluo-4-AM dissolved in dimethyl sulfoxide containing 20% pluronic acid (Sigma-Aldrich, Oakville, ON, Canada). Neurons and glia, stained in an area of 150-300 μm diameter, were imaged at 30-75 μm depths for several hours at scanning rates of 2.5 Hz that are sufficient to resolve peaks of inspiratory-related [Ca 2+ ] i rises ( (Ruangkittisakul et al 2006( (Ruangkittisakul et al , 2012.…”

Section: Recording Of Nerve and Neuronal Activities In Vitromentioning

confidence: 99%

Release of ATP by pre‐Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca²⁺‐dependent P2Y₁ receptor mechanism

Rajani

Zhang

Jalubula

et al. 2017

The Journal of Physiology

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112

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The hypoxic ventilatory response (HVR) is biphasic, consisting of a phase I increase in ventilation followed by a secondary depression (to a steady-state phase II) that can be life-threatening in premature infants who suffer from frequent apnoeas and respiratory depression. ATP released in the ventrolateral medulla oblongata during hypoxia attenuates the secondary depression. We explored a working hypothesis that vesicular release of ATP by astrocytes in the pre-Bötzinger Complex (preBötC) inspiratory rhythm-generating network acts via P2Y receptors to mediate this effect. Blockade of vesicular exocytosis in preBötC astrocytes bilaterally (using an adenoviral vector to specifically express tetanus toxin light chain in astrocytes) reduced the HVR in anaesthetized rats, indicating that exocytotic release of a gliotransmitter within the preBötC contributes to the hypoxia-induced increases in ventilation. Unilateral blockade of P2Y receptors in the preBötC via local antagonist injection enhanced the secondary respiratory depression, suggesting that a significant component of the phase II increase in ventilation is mediated by ATP acting at P2Y receptors. In vitro responses of the preBötC inspiratory network, preBötC inspiratory neurons and cultured preBötC glia to purinergic agents demonstrated that the P2Y receptor-mediated increase in fictive inspiratory frequency involves Ca recruitment from intracellular stores leading to increases in intracellular Ca ([Ca ] ) in inspiratory neurons and glia. These data suggest that ATP is released by preBötC astrocytes during hypoxia and acts via P2Y receptors on inspiratory neurons (and/or glia) to evoke Ca release from intracellular stores and an increase in ventilation that counteracts the hypoxic respiratory depression.

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“…Moreover, extrinsic conditions, like the composition of the aCSF solution and bath temperature during the preparation and incubation (or recovery), may vary between paradigms ( Kirov et al, 2004 ; Ting et al, 2018 ), and bacterial growth can cause an increase in endotoxins ( Terenzi et al, 1995 ; Buskila et al, 2014 ; P. Wang et al, 2019 ). Developmental age also plays a critical role, as acute brain slices prepared from younger animals are more resilient to injury ( Ballanyi, 2012 ; Ting et al, 2014 ). In our hands, using neonatal acute brain slices, we found that 75% of injured cells were localized to the zone extending from the exposed surface to a depth of ∼90 µm, increasing to a depth of ∼125 µm after 3–5 h of incubation.…”

Section: Discussionmentioning

confidence: 99%

Trauma in Neonatal Acute Brain Slices Alters Calcium and Network Dynamics and Causes Calpain-Mediated Cell Death

Suryavanshi,

Baule,

Glykys

2024

eNeuro

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Preparing acute brain slices produces trauma that mimics severe penetrating brain injury. In neonatal acute brain slices, the spatiotemporal characteristics of trauma-induced calcium dynamics in neurons and its effect on network activity are relatively unknown. Using multiphoton laser scanning microscopy of the somatosensory neocortex in acute neonatal mouse brain slices (P8-12), we simultaneously imaged neuronal Ca2+dynamics (GCaMP6s) and cytotoxicity (propidium iodide or PI) to determine the relationship between cytotoxic Ca2+loaded neurons (GCaMP-filled) and cell viability at different depths and incubation times. PI+-cells and GCaMP-filled neurons were abundant at the surface of the slices, with an exponential decrease with depth. Regions with high PI+-cells correlated with elevated neuronal and neuropil Ca2+. The number of PI+-cells and GCaMP-filled neurons increased with prolonged incubation. GCaMP-filled neurons did not participate in stimulus-evoked or seizure-evoked network activity. Significantly, the superficial tissue, with a higher degree of trauma-induced injury, showed attenuated seizure-related neuronal Ca2+responses. Calpain inhibition prevented the increase in PI+-cells and GCaMP-filled neurons in the deep tissue and during prolonged incubation times. Isoform-specific pharmacological inhibition implicated calpain-2 as a significant contributor to trauma-induced injury in acute slices. Our results show a calpain-mediated spatiotemporal relationship between cell death and aberrant neuronal Ca2+load in acute neonatal brain slices. Also, we demonstrate that neurons in acute brain slices exhibit altered physiology depending on the degree of trauma-induced injury. Blocking calpains may be a therapeutic option to prevent acute neuronal death during traumatic brain injury in the young brain.Significance statementThis is the first study to characterize the spatiotemporal dynamics of neocortical injury in acute neonatal slices, mimicking severe penetrating traumatic brain injury, using PI labeling and elevated neuronal Ca2+load as markers for cytotoxicity. We found depth- and time-dependent neuronal damage, leading to altered neuronal responses. Elevate neuronal Ca2+and cytotoxicity were mitigated by pharmacologically inhibiting calpains, a family of Ca2+-dependent proteases involved in multiple cell death mechanisms. Our study provides evidence for injury-dependent neuronal and circuit function alterations in neonatal acute brain slices. Calpain inhibition decreased trauma-induced cell death in the neonatal brain, identifying them as potential therapeutic targets at this age.

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Anatomically “Calibrated” Isolated Respiratory Networks from Newborn Rodents

Cited by 19 publications

References 92 publications

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Release of ATP by pre‐Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca²⁺‐dependent P2Y₁ receptor mechanism

Trauma in Neonatal Acute Brain Slices Alters Calcium and Network Dynamics and Causes Calpain-Mediated Cell Death

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Anatomically “Calibrated” Isolated Respiratory Networks from Newborn Rodents

Cited by 19 publications

References 92 publications

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks

Release of ATP by pre‐Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca2+‐dependent P2Y1 receptor mechanism

Trauma in Neonatal Acute Brain Slices Alters Calcium and Network Dynamics and Causes Calpain-Mediated Cell Death

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Release of ATP by pre‐Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca²⁺‐dependent P2Y₁ receptor mechanism