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Rickard AG, Zhuang M, DeRosa CA, Dewhirst MW, Fraser CL, Palmer GM. Quantifying the effects of anesthesia on intracellular oxygen via low-cost portable microscopy using dual-emissive nanoparticles. BIOMEDICAL OPTICS EXPRESS 2022; 13:3869-3881. [PMID: 35991919 PMCID: PMC9352295 DOI: 10.1364/boe.456125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/13/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Intracellular oxygenation is an important parameter for numerous biological studies. While there are a variety of methods available for acquiring in vivo measurements of oxygenation in animal models, most are dependent on indirect oxygen measurements, restraints, or anesthetization. A portable microscope system using a Raspberry Pi computer and Pi Camera was developed for attaching to murine dorsal window chambers. Dual-emissive boron nanoparticles were used as an oxygen-sensing probe while mice were imaged in awake and anesthetized states. The portable microscope system avoids altered in vivo measurements due to anesthesia or restraints while enabling increased continual acquisition durations.
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Affiliation(s)
- Ashlyn G. Rickard
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - Meng Zhuang
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | | | - Mark W. Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | | | - Gregory M. Palmer
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
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An Angiotensin-Responsive Connection from the Lamina Terminalis to the Paraventricular Nucleus of the Hypothalamus Evokes Vasopressin Secretion to Increase Blood Pressure in Mice. J Neurosci 2020; 41:1429-1442. [PMID: 33328294 DOI: 10.1523/jneurosci.1600-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 11/29/2020] [Accepted: 12/03/2020] [Indexed: 12/22/2022] Open
Abstract
Blood pressure is controlled by endocrine, autonomic, and behavioral responses that maintain blood volume and perfusion pressure at levels optimal for survival. Although it is clear that central angiotensin type 1a receptors (AT1aR; encoded by the Agtr1a gene) influence these processes, the neuronal circuits mediating these effects are incompletely understood. The present studies characterize the structure and function of AT1aR neurons in the lamina terminalis (containing the median preoptic nucleus and organum vasculosum of the lamina terminalis), thereby evaluating their roles in blood pressure control. Using male Agtr1a-Cre mice, neuroanatomical studies reveal that AT1aR neurons in the area are largely glutamatergic and send projections to the paraventricular nucleus of the hypothalamus (PVN) that appear to synapse onto vasopressin-synthesizing neurons. To evaluate the functionality of these lamina terminalis AT1aR neurons, we virally delivered light-sensitive opsins and then optogenetically excited or inhibited the neurons while evaluating cardiovascular parameters or fluid intake. Optogenetic excitation robustly elevated blood pressure, water intake, and sodium intake, while optogenetic inhibition produced the opposite effects. Intriguingly, optogenetic excitation of these AT1aR neurons of the lamina terminalis also resulted in Fos induction in vasopressin neurons within the PVN and supraoptic nucleus. Further, within the PVN, selective optogenetic stimulation of afferents that arise from these lamina terminalis AT1aR neurons induced glutamate release onto magnocellular neurons and was sufficient to increase blood pressure. These cardiovascular effects were attenuated by systemic pretreatment with a vasopressin-1a-receptor antagonist. Collectively, these data indicate that excitation of lamina terminalis AT1aR neurons induces neuroendocrine and behavioral responses that increase blood pressure.SIGNIFICANCE STATEMENT Hypertension is a widespread health problem and risk factor for cardiovascular disease. Although treatments exist, a substantial percentage of patients suffer from "drug-resistant" hypertension, a condition associated with increased activation of brain angiotensin receptors, enhanced sympathetic nervous system activity, and elevated vasopressin levels. The present study highlights a role for angiotensin Type 1a receptor expressing neurons located within the lamina terminalis in regulating endocrine and behavioral responses that are involved in maintaining cardiovascular homeostasis. More specifically, data presented here reveal functional excitatory connections between angiotensin-sensitive neurons in the lamina terminals and vasopressin neurons in the paraventricular nucleus of the hypothalamus, and further indicate that activation of this circuit raises blood pressure. These neurons may be a promising target for antihypertensive therapeutics.
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Tsurugizawa T, Tamada K, Ono N, Karakawa S, Kodama Y, Debacker C, Hata J, Okano H, Kitamura A, Zalesky A, Takumi T. Awake functional MRI detects neural circuit dysfunction in a mouse model of autism. SCIENCE ADVANCES 2020; 6:eaav4520. [PMID: 32076634 PMCID: PMC7002125 DOI: 10.1126/sciadv.aav4520] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/22/2019] [Indexed: 05/05/2023]
Abstract
MRI has potential as a translational approach from rodents to humans. However, given that mouse functional MRI (fMRI) uses anesthetics for suppression of motion, it has been difficult to directly compare the result of fMRI in "unconsciousness" disease model mice with that in "consciousness" patients. We develop awake fMRI to investigate brain function in 15q dup mice, a copy number variation model of autism. Compared to wild-type mice, we find that 15q dup is associated with whole-brain functional hypoconnectivity and diminished fMRI responses to odors of stranger mice. Ex vivo diffusion MRI reveals widespread anomalies in white matter ultrastructure in 15q dup mice, suggesting a putative anatomical substrate for these functional hypoconnectivity. We show that d-cycloserine (DCS) treatment partially normalizes these anormalies in the frontal cortex of 15q dup mice and rescues some social behaviors. Our results demonstrate the utility of awake rodent fMRI and provide a rationale for further investigation of DCS therapy.
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Affiliation(s)
- Tomokazu Tsurugizawa
- NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA Saclay, Gif-sur-Yvette 91191, France
- Corresponding author. (T.Ts.); (T.Ta.)
| | - Kota Tamada
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Nobukazu Ono
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Sachise Karakawa
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Yuko Kodama
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Clement Debacker
- NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA Saclay, Gif-sur-Yvette 91191, France
| | - Junichi Hata
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology, Keio University School of Medicine, Shinjuku, Tokyo 160-8585, Japan
| | - Hideyuki Okano
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology, Keio University School of Medicine, Shinjuku, Tokyo 160-8585, Japan
| | - Akihiko Kitamura
- Institute for Innovation, Ajinomoto Co. Inc., Kawasaki 210-8681, Japan
| | - Andrew Zalesky
- Melbourne Neuropsychiatry Centre and Department of Biomedical Engineering, University of Melbourne, Victoria 3010, Australia
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Chuo, Kobe 650-0017, Japan
- Corresponding author. (T.Ts.); (T.Ta.)
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Revell DZ, Yoder BK. Intravital visualization of the primary cilium, tubule flow, and innate immune cells in the kidney utilizing an abdominal window imaging approach. Methods Cell Biol 2019; 154:67-83. [PMID: 31493822 DOI: 10.1016/bs.mcb.2019.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The renal primary cilium is a small microtubule-based appendage thought to have mechano/chemosensory roles detecting changes in the fluid passing through the nephron. Mutations affecting cilium structure or function of ciliary-localized proteins result in a spectrum of diseases termed ciliopathies, with prevalent phenotypes such as the formation of renal cysts and fibrosis. While many studies have been conducted using fixed kidney sections or live imaging of cells in culture to investigate the cilium, examination in the context of a living murine kidney remains to be conducted. Previously, our lab generated the SSTR3GFP mouse to study cilium dynamics in vivo and found novel cilium behaviors that occurred following alteration of heart rate, blood pressure, and tubule flow. In this manuscript, we utilize multiple transgenic mouse models and an abdominal window imaging approach to observe primary cilia and tubule flow dynamics, immune cell movement, and renal Ca2+ signaling as it occurs in real time within a live mouse kidney. We present this window method as an approach that can be used in combination with various fluorescently labeled transgenic mice to investigate renal physiology, pathology, and function in vivo in longitudinal studies for as long as 5weeks.
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Affiliation(s)
- Dustin Z Revell
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States.
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Lindsay A, Larson AA, Verma M, Ervasti JM, Lowe DA. Isometric resistance training increases strength and alters histopathology of dystrophin-deficient mouse skeletal muscle. J Appl Physiol (1985) 2018; 126:363-375. [PMID: 30571283 DOI: 10.1152/japplphysiol.00948.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutation to the dystrophin gene causes skeletal muscle weakness in patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD). Deliberation continues regarding implications of prescribing exercise for these patients. The purpose of this study was to determine whether isometric resistance exercise (~10 tetanic contractions/session) improves skeletal muscle strength and histopathology in the mdx mouse model of DMD. Three isometric training sessions increased in vivo isometric torque (22%) and contractility rates (54%) of anterior crural muscles of mdx mice. Mice expressing a BMD-causing missense mutated dystrophin on the mdx background showed comparable increases in torque (22%), while wild-type mice showed less change (11%). Increases in muscle function occurred within 1 h and peaked 3 days posttraining; however, the adaptation was lost after 7 days unless retrained. Six isometric training sessions over 4 wk caused increased isometric torque (28%) and contractility rates (22-28%), reduced fibrosis, as well as greater uniformity of fiber cross-sectional areas, fewer embryonic myosin heavy-chain-positive fibers, and more satellite cells in tibialis anterior muscle compared with the contralateral untrained muscle. Ex vivo functional analysis of isolated extensor digitorum longus (EDL) muscle from the trained hindlimb revealed greater absolute isometric force, lower passive stiffness, and a lower susceptibility to eccentric contraction-induced force loss compared with untrained EDL muscle. Overall, these data support the concept that exercise training in the form of isometric tetanic contractions can improve contractile function of dystrophin-deficient muscle, indicating a potential role for enhancing muscle strength in patients with DMD and BMD. NEW & NOTEWORTHY We focused on adaptive responses of dystrophin-deficient mouse skeletal muscle to isometric contraction training and report that in the absence of dystrophin (or in the presence of a mutated dystrophin), strength and muscle histopathology are improved. Results suggest that the strength gains are associated with fiber hypertrophy, reduced fibrosis, increased number of satellite cells, and blunted eccentric contraction-induced force loss in vitro. Importantly, there was no indication that the isometric exercise training was deleterious to dystrophin-deficient muscle.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
| | - Mayank Verma
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota.,Medical Scientist Training Program, University of Minnesota Medical School , Minneapolis, Minnesota
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota
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Constantinides C, Murphy K. Molecular and Integrative Physiological Effects of Isoflurane Anesthesia: The Paradigm of Cardiovascular Studies in Rodents using Magnetic Resonance Imaging. Front Cardiovasc Med 2016; 3:23. [PMID: 27525256 PMCID: PMC4965459 DOI: 10.3389/fcvm.2016.00023] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/04/2016] [Indexed: 12/19/2022] Open
Abstract
To-this-date, the exact molecular, cellular, and integrative physiological mechanisms of anesthesia remain largely unknown. Published evidence indicates that anesthetic effects are multifocal and occur in a time-dependent and coordinated manner, mediated via central, local, and peripheral pathways. Their effects can be modulated by a range of variables, and their elicited end-effect on the integrative physiological response is highly variable. This review summarizes the major cellular and molecular sites of anesthetic action with a focus on the paradigm of isoflurane (ISO) - the most commonly used anesthetic nowadays - and its use in prolonged in vivo rodent studies using imaging modalities, such as magnetic resonance imaging (MRI). It also presents established evidence for normal ranges of global and regional physiological cardiac function under ISO, proposes optimal, practical methodologies relevant to the use of anesthetic protocols for MRI and outlines the beneficial effects of nitrous oxide supplementation.
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Affiliation(s)
- Christakis Constantinides
- Chi Biomedical Ltd., Nicosia, Cyprus; Division of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Kathy Murphy
- Division of Biomedical Sciences, University of Oxford , Oxford , UK
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Michaelides M, Georgiadou S, Constantinides C. In vivo epicardial force and strain characterisation in normal and MLP-knockout murine hearts. Physiol Meas 2015; 36:1573-90. [PMID: 26057415 DOI: 10.1088/0967-3334/36/7/1573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The study's objective is to quantify in vivo epicardial force and strain in the normal and transgenic myocardium using microsensors.Male mice (n = 39), including C57BL/6 (n = 26), 129/Sv (n = 5), wild-type (WT) C57 × 129Sv (n = 5), and muscle LIM protein (MLP) knock-out (n = 3), were studied under 1.5% isoflurane anaesthesia. Microsurgery allowed the placement of two piezoelectric crystals at longitudinal epicardial loci at the basal, middle, and apical LV regions, and the independent (and/or concurrent) placement of a cantilever force sensor. The findings demonstrate longitudinal contractile and relaxation strains that ranged between 4.8-9.3% in the basal, middle, and apical regions of C57BL/6 mice, and in the mid-ventricular regions of 129/Sv, WT, and MLP mice. Measured forces ranged between 3.1-8.9 mN. The technique's feasibility is also demonstrated in normal mice following afterload, occlusion-reperfusion challenges.Furthermore, the total mid-ventricular forces developed in MLP mice were significantly reduced compared to the WT controls (5.9 ± 0.4 versus 8.9 ± 0.2 mN, p < 0.0001), possibly owing to the fibrotic and stiffer myocardium. No significant strain differences were noted between WT and MLP mice.The possibility of quantifying in vivo force and strain from the normal murine heart is demonstrated with a potential usefulness in the characterisation of transgenic and diseased mice, where regional myocardial function may be significantly altered.
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Affiliation(s)
- M Michaelides
- Department of Mechanical and Manufacturing Engineering, School of Engineering, University of Cyprus, Nicosia, Cyprus. Lecturer, Department of Sport and Exercise Science, UCLan Cyprus, University Avenue 12-14, Pyla 7080, Cyprus
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Kashefi P, Montazeri K, Hashemi ST. Effect of hypertonic saline on hypotension following induction of general anesthesia: A randomized controlled trial. Adv Biomed Res 2014; 3:183. [PMID: 25250297 PMCID: PMC4166055 DOI: 10.4103/2277-9175.140088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 06/18/2014] [Indexed: 11/19/2022] Open
Abstract
Background: The aim of this study was to examine the effects of preoperatively administered i.v. hypertonic saline on hypotension following induction of general anesthesia. Materials and Methods: Fifty-four patients who scheduled for elective surgery were randomly allocated to two groups of 27 patients who received hypertonic saline 5% (2.3 ml/kg) or received normal saline (13 ml/kg). Infusion of hypertonic saline was done half an hour before induction of anesthesia during 30 minutes. Anesthesia was conducted in a standard protocol for all patients. Age, sex, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), heart rate (HR) and mean arterial pressure (MAP) were assessed in all patients. Results: The mean age of patients was 36.68 ± 10.8 years. Forty percent of patients were male. The mean SBP at min 2 and min 5, mean of DBP at min 2, 5, and 15, mean of HR at all time points and mean of MAP at min 2 and 15 between groups were no significantly different (P > 0.05), but mean of SBP at min 10 and 15, mean of DBP at min 10, and mean of MAP at min 5 and 10 in hypertonic saline group was significantly more than the normal group (P < 0.05). Trend of SBP, DBP, HR and MAP between groups were not significantly different (P > 0.05). Conclusions: Infusion of hypertonic saline 5% (2.3 mg/kg) before the general anesthesia led to a useful reduction in MAP and reduced heart rate, with no episodes of severe hypotension.
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Affiliation(s)
- Parviz Kashefi
- Department of Anesthesia, Medical School, St-Alzahra Medical Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Kamran Montazeri
- Department of Anesthesia, Medical School, St-Alzahra Medical Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Taghi Hashemi
- Department of Anesthesia, Medical School, St-Alzahra Medical Center, Isfahan University of Medical Sciences, Isfahan, Iran
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Constantinides C, Angeli S, Kossivas F, Ktorides P. Underestimation of Murine Cardiac Hemodynamics Using Invasive Catheters: Errors, Limitations, and Remedies. Cardiovasc Eng Technol 2012. [DOI: 10.1007/s13239-012-0084-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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