1
|
Saunders SE, Santin JM. Compensatory changes in GABAergic inhibition are differentially expressed in the respiratory network to promote function following hibernation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.09.561534. [PMID: 37873475 PMCID: PMC10592683 DOI: 10.1101/2023.10.09.561534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The respiratory network must produce consistent output throughout an animal's life. Although respiratory motor plasticity is well appreciated, how plasticity mechanisms are organized to give rise to robustness following perturbations that disrupt breathing is less clear. During underwater hibernation, respiratory neurons of bullfrogs remain inactive for months, providing a large disturbance that must be overcome to restart breathing. As a result, motoneurons upregulate excitatory synapses to promote the drive to breathe. Reduced inhibition often occurs in parallel with increased excitation, yet the loss of inhibition can destabilize respiratory motor output. Thus, we hypothesized that GABAergic inhibition would decrease following hibernation, but this decrease would be expressed differentially throughout the network. We confirmed that respiratory frequency was under control of GABAAR signaling, but after hibernation, it became less reliant on inhibition. The loss of inhibition was confined to the respiratory rhythm-generating centers: non-respiratory motor activity and large seizure-like bursts were similarly triggered by GABAA receptor blockade in controls and hibernators. Supporting reduced presynaptic GABA release, firing rate of respiratory motoneurons was constrained by a phasic GABAAR tone, but after hibernation, this tone was decreased despite the same postsynaptic receptor strength as controls. Thus, selectively reducing inhibition in respiratory premotor networks promotes stability of breathing, while wholesale loss of GABAARs causes non-specific hyperexcitability throughout the brainstem. These results suggest that different parts of the respiratory network select distinct strategies involving either excitation (motoneurons) or inhibition (rhythm generator) to minimize pathological network states when engaging plasticity that protects the drive to breathe.
Collapse
Affiliation(s)
- Sandy E Saunders
- University of Missouri-Columbia, Missouri, United States of America
| | - Joseph M Santin
- University of Missouri-Columbia, Missouri, United States of America
| |
Collapse
|
2
|
Onimaru H, Fukushi I, Ikeda K, Yazawa I, Takeda K, Okada Y, Izumizaki M. Cell Responses of the Ventrolateral Medulla to PAR1 Activation and Changes in Respiratory Rhythm in Newborn Rat En Bloc Brainstem-Spinal Cord Preparations. Neuroscience 2023; 528:89-101. [PMID: 37557948 DOI: 10.1016/j.neuroscience.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023]
Abstract
Proteinase-activated receptor-1 (PAR1) is expressed in astrocytes of various brain regions, and its activation is involved in the modulation of neuronal activity. Here, we report effects of PAR1 selective agonist TFLLR on respiratory rhythm generation in brainstem-spinal cord preparations. Preparations were isolated from newborn rats (P0-P4) under deep isoflurane anesthesia and were transversely cut at the rostral medulla. Preparations were superfused with artificial cerebrospinal fluid (25-26 °C), and inspiratory C4 ventral root activity was monitored. The responses to TFLLR of cells close to the cut surface were detected by calcium imaging or membrane potential recordings. Application of 10 μM TFLLR (4 min) induced a rapid and transient increase of calcium signal in cells of the ventrolateral respiratory regions of the medulla. More than 88% of responding cells (223/254 cells from 13 preparations) were also activated by low (0.2 mM) K+ solution, suggesting that they were astrocytes. Immunohistochemical examination demonstrated that PAR1 was expressed on many astrocytes. Respiratory-related neurons in the medulla were transiently hyperpolarized (-1.8 mV) during 10 μM TFLLR application, followed by weak membrane depolarization after washout. C4 burst rate decreased transiently in response to application of TFLLR, followed by a slight increase. The inhibitory effect was partially blocked by 50 μM theophylline. In conclusion, activation of astrocytes via PAR1 resulted in a decrease of inspiratory C4 burst rate in association with transient hyperpolarization of respiratory-related neurons. After washout, slow and weak excitatory responses appeared. Adenosine may be partially involved in the inhibitory effect of PAR1 activation.
Collapse
Affiliation(s)
- Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan.
| | - Isato Fukushi
- Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori, Japan; Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Keiko Ikeda
- Department of Oral Physiology, Showa University School of Dentistry, Tokyo, Japan
| | - Itaru Yazawa
- Department of Food & Nutrition, Kyushu Nutrition Welfare University, Fukuoka, Japan
| | - Kotaro Takeda
- Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Masahiko Izumizaki
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
| |
Collapse
|
3
|
Adenosine A1 receptor: A neuroprotective target in light induced retinal degeneration. PLoS One 2018; 13:e0198838. [PMID: 29912966 PMCID: PMC6005487 DOI: 10.1371/journal.pone.0198838] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/25/2018] [Indexed: 02/04/2023] Open
Abstract
Light induced retinal degeneration (LIRD) is a useful model that resembles human retinal degenerative diseases. The modulation of adenosine A1 receptor is neuroprotective in different models of retinal injury. The aim of this work was to evaluate the potential neuroprotective effect of the modulation of A1 receptor in LIRD. The eyes of rats intravitreally injected with N6-cyclopentyladenosine (CPA), an A1 agonist, which were later subjected to continuous illumination (CI) for 24 h, showed retinas with a lower number of apoptotic nuclei and a decrease of Glial Fibrillary Acidic Protein (GFAP) immunoreactive area than controls. Lower levels of activated Caspase 3 and GFAP were demonstrated by Western Blot (WB) in treated animals. Also a decrease of iNOS, TNFα and GFAP mRNA was demonstrated by RT-PCR. A decrease of Iba 1+/MHC-II+ reactive microglial cells was shown by immunohistochemistry. Electroretinograms (ERG) showed higher amplitudes of a-wave, b-wave and oscillatory potentials after CI compared to controls. Conversely, the eyes of rats intravitreally injected with dipropylcyclopentylxanthine (DPCPX), an A1 antagonist, and subjected to CI for 24 h, showed retinas with a higher number of apoptotic nuclei and an increase of GFAP immunoreactive area compared to controls. Also, higher levels of activated Caspase 3 and GFAP were demonstrated by Western Blot. The mRNA levels of iNOS, nNOS and inflammatory cytokines (IL-1β and TNFα) were not modified by DPCPX treatment. An increase of Iba 1+/MHC-II+ reactive microglial cells was shown by immunohistochemistry. ERG showed that the amplitudes of a-wave, b-wave, and oscillatory potentials after CI were similar to control values. A single pharmacological intervention prior illumination stress was able to swing retinal fate in opposite directions: CPA was neuroprotective, while DPCPX worsened retinal damage. In summary, A1 receptor agonism is a plausible neuroprotective strategy in LIRD.
Collapse
|
4
|
Lin ST, Ohbayashi M, Yamamoto T, Onimaru H, Kogo M. Effects of riluzole on spinal seizure-like activity in the brainstem-spinal cord preparation of newborn rat. Neurosci Res 2017; 125:46-53. [PMID: 28728911 DOI: 10.1016/j.neures.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/24/2017] [Accepted: 07/10/2017] [Indexed: 10/19/2022]
Abstract
Riluzole blocks persistent Na+ current, inhibits generation of neuronal bursts and decreases glutamate-induced excitotoxicity. In previous studies of respiratory activity, riluzole suppressed inspiratory-related burst generation activity in rat slice or en bloc preparations. We examined riluzole's effects on inspiratory burst generation and drug-induced seizure-like activity in newborn rat en bloc preparations. Medulla-spinal cord preparations from postnatal day 0-3 Wistar rats were isolated under deep isoflurane anesthesia and were superfused with artificial cerebrospinal fluid equilibrated with 95% O2 and 5% CO2, pH 7.4, at 25-26°C. Inspiratory activity was monitored from the fourth cervical ventral root. Seizure-like activity was induced by application of 20μM DL-threo-β-benzyloxyasparatate (TBOA, a glutamate uptake blocker preferentially acting on astrocytes) or coadministration of GABAA antagonist bicuculline (10μM) and glycine antagonist strychnine (10μM). Pretreatment and co-application with 10μM riluzole abolished the seizure-like burst activity induced by TBOA or bicuculline/strychnine. N-methyl-d-aspartic acid receptor antagonist MK801 (10μM) also depressed this activity. Riluzole may attenuate excessive glutamate action involved in pathological hyperexcitability of motor neurons with no major effect on generation of respiratory activity. Riluzole at the optimal dose could be a potential treatment to protect drug-induced epileptic brain tissue from excitotoxic damage without inducing respiratory suppression.
Collapse
Affiliation(s)
- Shih Tien Lin
- Division of Pharmacotherapeutics, Department of Clinical Pharmacy, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Masayuki Ohbayashi
- Division of Pharmacotherapeutics, Department of Clinical Pharmacy, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Toshinori Yamamoto
- Division of Pharmacotherapeutics, Department of Clinical Pharmacy, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan.
| | - Mari Kogo
- Division of Pharmacotherapeutics, Department of Clinical Pharmacy, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| |
Collapse
|
5
|
Susceptibility to seizure-induced sudden death in DBA/2 mice is altered by adenosine. Epilepsy Res 2016; 124:49-54. [DOI: 10.1016/j.eplepsyres.2016.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 04/21/2016] [Accepted: 05/17/2016] [Indexed: 02/06/2023]
|
6
|
Abdelfattah AS, Farhi SL, Zhao Y, Brinks D, Zou P, Ruangkittisakul A, Platisa J, Pieribone VA, Ballanyi K, Cohen AE, Campbell RE. A Bright and Fast Red Fluorescent Protein Voltage Indicator That Reports Neuronal Activity in Organotypic Brain Slices. J Neurosci 2016; 36:2458-72. [PMID: 26911693 PMCID: PMC4764664 DOI: 10.1523/jneurosci.3484-15.2016] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/16/2015] [Accepted: 01/15/2016] [Indexed: 01/09/2023] Open
Abstract
Optical imaging of voltage indicators based on green fluorescent proteins (FPs) or archaerhodopsin has emerged as a powerful approach for detecting the activity of many individual neurons with high spatial and temporal resolution. Relative to green FP-based voltage indicators, a bright red-shifted FP-based voltage indicator has the intrinsic advantages of lower phototoxicity, lower autofluorescent background, and compatibility with blue-light-excitable channelrhodopsins. Here, we report a bright red fluorescent voltage indicator (fluorescent indicator for voltage imaging red; FlicR1) with properties that are comparable to the best available green indicators. To develop FlicR1, we used directed protein evolution and rational engineering to screen libraries of thousands of variants. FlicR1 faithfully reports single action potentials (∼3% ΔF/F) and tracks electrically driven voltage oscillations at 100 Hz in dissociated Sprague Dawley rat hippocampal neurons in single trial recordings. Furthermore, FlicR1 can be easily imaged with wide-field fluorescence microscopy. We demonstrate that FlicR1 can be used in conjunction with a blue-shifted channelrhodopsin for all-optical electrophysiology, although blue light photoactivation of the FlicR1 chromophore presents a challenge for applications that require spatially overlapping yellow and blue excitation.
Collapse
Affiliation(s)
- Ahmed S Abdelfattah
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Samouil L Farhi
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Yongxin Zhao
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Daan Brinks
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Peng Zou
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | | | - Jelena Platisa
- The John B. Pierce Laboratory, Inc., New Haven, Connecticut 06519, Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Vincent A Pieribone
- The John B. Pierce Laboratory, Inc., New Haven, Connecticut 06519, Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Klaus Ballanyi
- Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Adam E Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, Department of Physics, Harvard University, Cambridge, Massachusetts 02138, and Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada,
| |
Collapse
|
7
|
Ruangkittisakul A, Sharopov S, Kantor C, Kuribayashi J, Mildenberger E, Luhmann H, Kilb W, Ballanyi K. Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks. Neuroscience 2015; 301:106-20. [DOI: 10.1016/j.neuroscience.2015.05.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/11/2015] [Accepted: 05/27/2015] [Indexed: 11/29/2022]
|
8
|
Takita K, Morimoto Y. Nociceptin/orphanin FQ slows inspiratory rhythm via its direct effects on the pre-Bötzinger complex. Respir Physiol Neurobiol 2015; 207:14-21. [PMID: 25500622 DOI: 10.1016/j.resp.2014.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
In a previous study, we showed that in an in vitro en bloc preparation of newborn rats perfused with standard [K(+)] (6.2mM) and high [K(+)] (11.2mM) artificial cerebrospinal fluid (aCSF), nociceptin/orphanin FQ (N/OFQ) suppresses bursting of pre-inspiratory neurons with 1:1 coupling to the fictive inspiration. However, it is unclear whether the pre-Bötzinger complex (preBötC) is involved in the N/OFQ-induced slowing. Using in vitro en bloc preparations with and without the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) perfused with high [K(+)] aCSF, we found the following: (1) there were no differences in the effects of N/OFQ on the inspiratory rhythm between the preparations with and without the RTN/pFRG, (2) N/OFQ decreased the input resistance of inspiratory neurons (Insps) in the preparations without the RTN/pFRG and suppressed their ectopic firing activities, and (3) N/OFQ suppressed the spontaneous firing of Insps under a chemical synaptic transmission blockade. In conclusion, it is possible that the preBötC is involved in N/OFQ-induced inspiratory rhythm slowing.
Collapse
Affiliation(s)
- Koichi Takita
- Department of Anesthesiology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
| | - Yuji Morimoto
- Department of Anesthesiology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| |
Collapse
|
9
|
Wu J, Abdelfattah AS, Miraucourt LS, Kutsarova E, Ruangkittisakul A, Zhou H, Ballanyi K, Wicks G, Drobizhev M, Rebane A, Ruthazer ES, Campbell RE. A long Stokes shift red fluorescent Ca2+ indicator protein for two-photon and ratiometric imaging. Nat Commun 2014; 5:5262. [PMID: 25358432 PMCID: PMC4920544 DOI: 10.1038/ncomms6262] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/12/2014] [Indexed: 11/09/2022] Open
Abstract
The introduction of calcium ion (Ca(2+)) indicators based on red fluorescent proteins (RFPs) has created new opportunities for multicolour visualization of intracellular Ca(2+) dynamics. However, one drawback of these indicators is that they have optimal two-photon excitation outside the near-infrared window (650-1,000 nm) where tissue is most transparent to light. To address this shortcoming, we developed a long Stokes shift RFP-based Ca(2+) indicator, REX-GECO1, with optimal two-photon excitation at <1,000 nm. REX-GECO1 fluoresces at 585 nm when excited at 480 nm or 910 nm by a one- or two-photon process, respectively. We demonstrate that REX-GECO1 can be used as either a ratiometric or intensiometric Ca(2+) indicator in organotypic hippocampal slice cultures (one- and two-photon) and the visual system of albino tadpoles (two-photon). Furthermore, we demonstrate single excitation wavelength two-colour Ca(2+) and glutamate imaging in organotypic cultures.
Collapse
Affiliation(s)
- Jiahui Wu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Ahmed S Abdelfattah
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Loïs S Miraucourt
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Neuroengineering Program, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Elena Kutsarova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Neuroengineering Program, McGill University, Montreal, Quebec, Canada H3A 2B4
| | | | - Hang Zhou
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Klaus Ballanyi
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Geoffrey Wicks
- Department of Physics, Montana State University, Bozeman, Montana 59717, USA
| | - Mikhail Drobizhev
- Department of Physics, Montana State University, Bozeman, Montana 59717, USA
| | - Aleksander Rebane
- 1] Department of Physics, Montana State University, Bozeman, Montana 59717, USA [2] National Institute of Chemical Physics and Biophysics, Tallinn, Estonia 12618
| | - Edward S Ruthazer
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Neuroengineering Program, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| |
Collapse
|
10
|
Mosca E, Ciechanski P, Roy A, Scheibli E, Ballanyi K, Wilson R. Methylxanthine reversal of opioid-induced respiratory depression in the neonatal rat: Mechanism and location of action. Respir Physiol Neurobiol 2014; 200:80-9. [DOI: 10.1016/j.resp.2014.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 02/02/2023]
|
11
|
Zhao Y, Abdelfattah AS, Zhao Y, Ruangkittisakul A, Ballanyi K, Campbell RE, Harrison DJ. Microfluidic cell sorter-aided directed evolution of a protein-based calcium ion indicator with an inverted fluorescent response. Integr Biol (Camb) 2014; 6:714-25. [PMID: 24840546 DOI: 10.1039/c4ib00039k] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We demonstrate a simple, low cost and disposable microfluidic fluorescence activated cell sorting system (μFACS) for directed evolution of fluorescent proteins (FP) and FP-based calcium ion (Ca(2+)) indicators. The system was employed to pre-screen libraries of up to 10(6) variants of a yellow FP-based Ca(2+) indicator (Y-GECO) with throughput up to 300 cells per s. Compared to traditional manual screening of FP libraries, this system accelerated the discovery of improved variants and saved considerable time and effort during the directed evolution of Y-GECO. Y-GECO1, the final product of the μFACS-aided directed evolution, has a unique fluorescence hue that places it in the middle of the spectral gap that separates the currently available green and orange FP-based Ca(2+) indicators, exhibits bright fluorescence in the resting (Ca(2+) free) state, and gives a large response to intracellular Ca(2+) fluctuations in live cells.
Collapse
Affiliation(s)
- Yongxin Zhao
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | | | | | | | | | | | | |
Collapse
|