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Barioni NO, Derakhshan F, Tenorio Lopes L, Onimaru H, Roy A, McDonald F, Scheibli E, Baghdadwala MI, Heidari N, Bharadia M, Ikeda K, Yazawa I, Okada Y, Harris MB, Dutschmann M, Wilson RJA. Novel oxygen sensing mechanism in the spinal cord involved in cardiorespiratory responses to hypoxia. Sci Adv 2022; 8:eabm1444. [PMID: 35333571 PMCID: PMC8956269 DOI: 10.1126/sciadv.abm1444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 02/04/2022] [Indexed: 05/05/2023]
Abstract
As blood oxygenation decreases (hypoxemia), mammals mount cardiorespiratory responses, increasing oxygen to vital organs. The carotid bodies are the primary oxygen chemoreceptors for breathing, but sympathetic-mediated cardiovascular responses to hypoxia persist in their absence, suggesting additional high-fidelity oxygen sensors. We show that spinal thoracic sympathetic preganglionic neurons are excited by hypoxia and silenced by hyperoxia, independent of surrounding astrocytes. These spinal oxygen sensors (SOS) enhance sympatho-respiratory activity induced by CNS asphyxia-like stimuli, suggesting they bestow a life-or-death advantage. Our data suggest the SOS use a mechanism involving neuronal nitric oxide synthase 1 (NOS1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). We propose NOS1 serves as an oxygen-dependent sink for NADPH in hyperoxia. In hypoxia, NADPH catabolism by NOS1 decreases, increasing availability of NADPH to NOX and launching reactive oxygen species-dependent processes, including transient receptor potential channel activation. Equipped with this mechanism, SOS are likely broadly important for physiological regulation in chronic disease, spinal cord injury, and cardiorespiratory crisis.
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Affiliation(s)
- Nicole O. Barioni
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Fatemeh Derakhshan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Luana Tenorio Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
| | - Arijit Roy
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Fiona McDonald
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Erika Scheibli
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Mufaddal I. Baghdadwala
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Negar Heidari
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Manisha Bharadia
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Keiko Ikeda
- Division of Internal Medicine, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Itaru Yazawa
- Global Research Center for Innovative Life Science, Peptide Drug Innovation, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan
| | - Yasumasa Okada
- Division of Internal Medicine, Murayama Medical Center, Musashimurayama, Tokyo, Japan
| | - Michael B. Harris
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA 90840, USA
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, 3052, Australia
| | - Richard J. A. Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Harris MB, Barrientos C, Bui A, Co M, Gill S, Lim S, Ly L, Nguyen M, Ortiz B, Parabo A, Phillips D, Rieger I, Shilleh A, Suree N, Tran A, Valdez V, Vu T, Taylor BE, Berlemont R. Pharyngeal Pumping Variability Assessment Reveals Subtle Mutant and Treatment Effects in the Nematode
C. elegans. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.07436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Andy Bui
- California State University Long Beach
| | - Mary Co
- California State University Long Beach
| | | | | | - Lily Ly
- California State University Long Beach
| | | | | | | | | | | | | | | | | | | | - Tien Vu
- California State University Long Beach
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Janes TA, Rousseau JP, Fournier S, Kiernan EA, Harris MB, Taylor BE, Kinkead R. Development of central respiratory control in anurans: The role of neurochemicals in the emergence of air-breathing and the hypoxic response. Respir Physiol Neurobiol 2019; 270:103266. [PMID: 31408738 PMCID: PMC7476778 DOI: 10.1016/j.resp.2019.103266] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/10/2019] [Accepted: 08/05/2019] [Indexed: 01/08/2023]
Abstract
Physiological and environmental factors impacting respiratory homeostasis vary throughout the course of an animal's lifespan from embryo to adult and can shape respiratory development. The developmental emergence of complex neural networks for aerial breathing dates back to ancestral vertebrates, and represents the most important process for respiratory development in extant taxa ranging from fish to mammals. While substantial progress has been made towards elucidating the anatomical and physiological underpinnings of functional respiratory control networks for air-breathing, much less is known about the mechanisms establishing these networks during early neurodevelopment. This is especially true of the complex neurochemical ensembles key to the development of air-breathing. One approach to this issue has been to utilize comparative models such as anuran amphibians, which offer a unique perspective into early neurodevelopment. Here, we review the developmental emergence of respiratory behaviours in anuran amphibians with emphasis on contributions of neurochemicals to this process and highlight opportunities for future research.
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Affiliation(s)
- Tara A Janes
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Jean-Philippe Rousseau
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Stéphanie Fournier
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
| | - Elizabeth A Kiernan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison Wisconsin, USA
| | - Michael B Harris
- Department of Biological Sciences, California State University Long Beach, California, USA
| | - Barbara E Taylor
- Department of Biological Sciences, California State University Long Beach, California, USA
| | - Richard Kinkead
- Department of Pediatrics, Université Laval & Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada.
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Reed MD, Iceman KE, Harris MB, Taylor BE. Buccal rhythmogenesis and CO 2 sensitivity in Lithobates catesbeianus tadpole brainstems across metamorphosis. Respir Physiol Neurobiol 2019; 268:103251. [PMID: 31279052 DOI: 10.1016/j.resp.2019.103251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 06/19/2019] [Accepted: 07/02/2019] [Indexed: 11/19/2022]
Abstract
Bullfrog tadpoles ventilate both the buccal cavity and lung. In isolated brainstems, the midbrain/pons influences CO2 responsiveness and timing of lung ventilatory bursting, depending on larval development. However, little is known about midbrain/pons influences on buccal burst patterns. As such, we investigated how removal of this region affects buccal burst shape and CO2 responsiveness across development. We measured facial nerve activity in brainstems isolated from tadpoles during early and late developmental stages, under normal and elevated levels of CO2. Brainstems were either left intact or transected by removing the midbrain/pons. In late stage preparations, buccal burst pattern differed between intact and reduced preparations, and bursts were responsive to elevated CO2 in these reduced preparations. These results suggest the midbrain/pons affects tadpole buccal burst pattern and CO2 responsiveness, perhaps similar to its influences on lung ventilation.
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Affiliation(s)
- Mitchell D Reed
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, United States.
| | - Kimberly E Iceman
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, United States; Department of Biology, Valparaiso University, Valparaiso, IN, 46383, United States
| | - Michael B Harris
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, United States; Department of Biology, California State University Long Beach, Long Beach, CA, 90840, United States
| | - Barbara E Taylor
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, United States; Department of Biology, California State University Long Beach, Long Beach, CA, 90840, United States
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Harris MB, Barrientos C, Bui A, Co M, Gill S, Lim S, Ly L, Ortiz B, Parabo A, Phillips D, Tran A, Valdez V, Vu T, Taylor BE, Berlemont R. Resolving Subtle Treatment Effects through Pharyngeal Pumping Variability Assessment in the Nematode
C. elegans. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.726.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | | | - Andy Bui
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Mary Co
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Sunny Gill
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Shelby Lim
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Lily Ly
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Brianna Ortiz
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Ashley Parabo
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Derek Phillips
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Adrian Tran
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Vanessa Valdez
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Tien Vu
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Barbara E Taylor
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Renaud Berlemont
- Biological SciencesCalifornia State University Long BeachLong BeachCA
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Harris MB, Shilleh A, Phillips D, Taylor BE, Berlemont R. WormBeat: A Strategy to Evaluate Pharyngeal Pumping Variability in the Nematode
C. elegans. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.726.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Ahmad Shilleh
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Derek Phillips
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Barbara E Taylor
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Renaud Berlemont
- Biological SciencesCalifornia State University Long BeachLong BeachCA
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Harris MB, Flores PH. A Novel Assessment of Metabolic Flexibility: Dynamic Metabolic Adjustments to Exercise. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.534.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Phillip H Flores
- Biological SciencesCalifornia State University Long BeachLong BeachCA
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Reed MD, Iceman KE, Harris MB, Taylor BE. The rostral medulla of bullfrog tadpoles contains critical lung rhythmogenic and chemosensitive regions across metamorphosis. Comp Biochem Physiol A Mol Integr Physiol 2018; 225:7-15. [PMID: 29890210 DOI: 10.1016/j.cbpa.2018.05.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/14/2018] [Accepted: 05/30/2018] [Indexed: 11/18/2022]
Abstract
The development of amphibian breathing provides insight into vertebrate respiratory control mechanisms. Neural oscillators in the rostral and caudal medulla drive ventilation in amphibians, and previous reports describe ventilatory oscillators and CO2 sensitive regions arise during different stages of amphibian metamorphosis. However, inconsistent findings have been enigmatic, and make comparisons to potential mammalian counterparts challenging. In the current study we assessed amphibian central CO2 responsiveness and respiratory rhythm generation during two different developmental stages. Whole-nerve recordings of respiratory burst activity in cranial and spinal nerves were made from intact or transected brainstems isolated from tadpoles during early or late stages of metamorphosis. Brainstems were transected at the level of the trigeminal nerve, removing rostral structures including the nucleus isthmi, midbrain, and locus coeruleus, or transected at the level of the glossopharyngeal nerve, removing the putative buccal oscillator and caudal medulla. Removal of caudal structures stimulated the frequency of lung ventilatory bursts and revealed a hypercapnic response in normally unresponsive preparations derived from early stage tadpoles. In preparations derived from late stage tadpoles, removal of rostral or caudal structures reduced lung burst frequency, while CO2 responsiveness was retained. Our results illustrate that structures within the rostral medulla are capable of sensing CO2 throughout metamorphic development. Similarly, the region controlling lung ventilation appears to be contained in the rostral medulla throughout metamorphosis. This work offers insight into the consistency of rhythmic respiratory and chemosensitive capacities during metamorphosis.
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Affiliation(s)
- Mitchell D Reed
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, United States.
| | - Kimberly E Iceman
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Biology, Valparaiso University, Valparaiso, IN 46383, United States
| | - Michael B Harris
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Biological Sciences, California State University Long Beach, Long Beach, CA 90840, United States
| | - Barbara E Taylor
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Biological Sciences, California State University Long Beach, Long Beach, CA 90840, United States
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Affiliation(s)
- Brianna Ortiz
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | | | - Elena Vayndorf
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
| | - Barbara E. Taylor
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Michael B. Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
- BiologyUniversity of Alaska FairbanksFairbanksAK
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Harris MB. The Fickle Cheerleader Hysteresis: Explaining Haemoglobin‐Oxygen Equilibrium through Non‐traditional Case‐Based Instruction in Physiology. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.629.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B. Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
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Harris MB, Berlemont R, Ortiz B, Taylor BE. Strategies to Assess Pharyngeal Pumping Variability in the Nematode
C. elegans. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.862.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B. Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Renaud Berlemont
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Brianna Ortiz
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Barbara E. Taylor
- Biological SciencesCalifornia State University Long BeachLong BeachCA
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Harris MB, Flores PH, Francis R. The Formula 1 Heart of the Etruscan Shrew
Suncus etruscus
: Using the Extreme to Exemplify Basic Principals in Cardiovascular Physiology. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.629.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B. Harris
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Phillip H. Flores
- Biological SciencesCalifornia State University Long BeachLong BeachCA
| | - Rohin Francis
- Institute of Cardiovascular ScienceUniversity College LondonLondonUnited Kingdom
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Hueffer K, Khatri S, Rideout S, Harris MB, Papke RL, Stokes C, Schulte MK. Rabies virus modifies host behaviour through a snake-toxin like region of its glycoprotein that inhibits neurotransmitter receptors in the CNS. Sci Rep 2017; 7:12818. [PMID: 28993633 PMCID: PMC5634495 DOI: 10.1038/s41598-017-12726-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/13/2017] [Indexed: 01/04/2023] Open
Abstract
Rabies virus induces drastic behaviour modifications in infected hosts. The mechanisms used to achieve these changes in the host are not known. The main finding of this study is that a region in the rabies virus glycoprotein, with homologies to snake toxins, has the ability to alter behaviour in animals through inhibition of nicotinic acetylcholine receptors present in the central nervous system. This finding provides a novel aspect to virus receptor interaction and host manipulation by pathogens in general. The neurotoxin-like region of the rabies virus glycoprotein inhibited acetylcholine responses of α4β2 nicotinic receptors in vitro, as did full length ectodomain of the rabies virus glycoprotein. The same peptides significantly altered a nicotinic receptor induced behaviour in C. elegans and increased locomotor activity levels when injected into the central nervous system of mice. These results provide a mechanistic explanation for the behavioural changes in hosts infected by rabies virus.
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Affiliation(s)
- Karsten Hueffer
- Department of Veterinary Medicine, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America.
| | - Shailesh Khatri
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, Pennsylvania, United States of America
| | - Shane Rideout
- Department of Biology and Wildlife & Institute of arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Michael B Harris
- Department of Biology and Wildlife & Institute of arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America.,Department of Biology, California State University Long Beach, Long Beach, California, United States of America
| | - Roger L Papke
- Department of Pharmacology & Therapeutics University of Florida, Gainesville, Florida, United States of America
| | - Clare Stokes
- Department of Pharmacology & Therapeutics University of Florida, Gainesville, Florida, United States of America
| | - Marvin K Schulte
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, Pennsylvania, United States of America
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Nagpal P, Akl MR, Ayoub NM, Tomiyama T, Cousins T, Tai B, Carroll N, Nyrenda T, Bhattacharyya P, Harris MB, Goy A, Pecora A, Suh KS. Pediatric Hodgkin lymphoma: biomarkers, drugs, and clinical trials for translational science and medicine. Oncotarget 2016; 7:67551-67573. [PMID: 27563824 PMCID: PMC5341896 DOI: 10.18632/oncotarget.11509] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 08/18/2016] [Indexed: 01/09/2023] Open
Abstract
Hodgkin lymphoma (HL) is a lymphoid malignancy that is typically derived from germinal-center B cells. EBV infection, mutations in NF-κB pathway genes, and genetic susceptibility are known risk factors for developing HL. CD30 and NF-κB have been identified as potential biomarkers in pediatric HL patients, and these molecules may represent therapeutic targets. Although current risk adapted and response based treatment approaches yield overall survival rates of >95%, treatment of relapse or refractory patients remains challenging. Targeted HL therapy with the antibody-drug conjugate Brentuximab vedotin (Bv) has proven to be superior to conventional salvage chemotherapy and clinical trials are being conducted to incorporate Bv into frontline therapy that substitutes Bv for alkylating agents to minimize secondary malignancies. The appearance of secondary malignancies has been a concern in pediatric HL, as these patients are at highest risk among all childhood cancer survivors. The risk of developing secondary leukemia following childhood HL treatment is 10.4 to 174.8 times greater than the risk in the general pediatric population and the prognosis is significantly poorer than the other hematological malignancies with a mortality rate of nearly 100%. Therefore, identifying clinically valuable biomarkers is of utmost importance to stratify and select patients who may or may not need intensive regimens to maintain optimal balance between maximal survival rates and averting late effects. Here we discuss epidemiology, risk factors, staging, molecular and genetic prognostic biomarkers, treatment for low and high-risk patients, and the late occurrence of secondary malignancies in pediatric HL.
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Affiliation(s)
- Poonam Nagpal
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Mohamed R. Akl
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Nehad M. Ayoub
- Department of Clinical Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
| | - Tatsunari Tomiyama
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Tasheka Cousins
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Betty Tai
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Nicole Carroll
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Themba Nyrenda
- Department of Research, Hackensack University Medical Center, Hackensack, NJ, USA
| | | | - Michael B. Harris
- Department of Pediatrics, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Andre Goy
- Clinical Divisions, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Andrew Pecora
- Clinical Divisions, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - K. Stephen Suh
- The Genomics and Biomarkers Program, The John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
- Department of Research, Hackensack University Medical Center, Hackensack, NJ, USA
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Abstract
The present article examines the period of time immediately following the completion of treatment for childhood cancer. The unique concerns experienced by families at this stage of the cancer treatment are examined, and the specific challenges that children face as they renegotiate roles and relationships that are necessary for successful reintegration into family, school, and community settings are discussed. Obstacles to successful reintegration that are frequently encountered by patients and families are reviewed, as well as variables that may promote optimal adjustment during this transitional period. The need for continued research in this area is highlighted, and specific research questions are identified. An emphasis is placed on applying a socioecological framework to research and clinical work with pediatric oncology patients at this stage of the cancer experience.
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Affiliation(s)
- Larissa E Labay
- Tomorrows Children's Institute, WFAN Building, 1st Floor; Hackensack University Medical Center, Hackensack, NJ 07601, USA.
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Hoffman M, Taylor BE, Harris MB. Evolution of lung breathing from a lungless primitive vertebrate. Respir Physiol Neurobiol 2015; 224:11-6. [PMID: 26476056 DOI: 10.1016/j.resp.2015.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022]
Abstract
Air breathing was critical to the terrestrial radiation and evolution of tetrapods and arose in fish. The vertebrate lung originated from a progenitor structure present in primitive boney fish. The origin of the neural substrates, which are sensitive to metabolically produced CO2 and which rhythmically activate respiratory muscles to match lung ventilation to metabolic demand, is enigmatic. We have found that a distinct periodic centrally generated rhythm, described as "cough" and occurring in lamprey in vivo and in vitro, is modulated by central sensitivity to CO2. This suggests that elements critical for the evolution of breathing in tetrapods, were present in the most basal vertebrate ancestors prior to the evolution of the lung. We propose that the evolution of breathing in all vertebrates occurred through exaptations derived from these critical basal elements.
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Affiliation(s)
- M Hoffman
- Department of Veterinary Medicine, University of Alaska Fairbanks, United States
| | - B E Taylor
- Institute of Arctic Biology, University of Alaska Fairbanks, United States; Department of Biology and Wildlife, University of Alaska Fairbanks, United States
| | - M B Harris
- Department of Veterinary Medicine, University of Alaska Fairbanks, United States; Institute of Arctic Biology, University of Alaska Fairbanks, United States; Department of Biology and Wildlife, University of Alaska Fairbanks, United States.
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Abstract
BACKGROUND Anesthetics have a profound influence on a myriad of autonomic processes. Mechanisms of general anesthesia, and how these mechanisms give rise to the multifaceted state of anesthesia, are largely unknown. The ascending and descending serotonin (5-HT) networks are key modulators of autonomic pathways, and are critically involved in homeostatic reflexes across the motor, somatosensory, limbic and autonomic systems. These 5-HT networks are thought to contribute to anesthetic effects, but how anesthetics affect 5-HT neuron function remains a pertinent question. We hypothesized that the volatile anesthetic isoflurane inhibits action potential discharge of medullary raphé 5-HT neurons. METHODS We conducted extracellular recordings on individual neurons in the medullary raphé region of the unanesthetized in situ perfused brainstem preparation to determine how exposure to isoflurane affects 5-HT neurons. We examined changes in 5-HT neuron baseline firing in response to treatment with either 1, 1.5, or 2% isoflurane. We measured isoflurane concentrations by gas chromatography-mass spectrometry (GC-MS) analysis. RESULTS Exposure to isoflurane inhibited action potential discharge in raphé 5-HT neurons. We document a concentration-dependent inhibition over a range of concentrations approximating isoflurane MAC (minimum alveolar concentration required for surgical anesthesia). Delivered concentrations of isoflurane were confirmed using GC-MS analysis. CONCLUSIONS These findings illustrate that halogenated anesthetics greatly affect 5-HT neuron firing and suggest 5-HT neuron contributions to mechanisms of general anesthesia.
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Affiliation(s)
- S L Johansen
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - K E Iceman
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - C R Iceman
- Department of Chemistry and Biochemistry, University of Alaska, Fairbanks, AK 99775, USA
| | - B E Taylor
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
| | - M B Harris
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA.
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Cho CH, Hsu L, Ferrone ML, Leonard DA, Harris MB, Zamani AA, Bono CM. Validation of multisociety combined task force definitions of abnormal disk morphology. AJNR Am J Neuroradiol 2015; 36:1008-13. [PMID: 25742982 PMCID: PMC7990579 DOI: 10.3174/ajnr.a4212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 10/24/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The multisociety task force descriptively defined abnormal lumbar disk morphology. We aimed to use their definitions to provide a higher level of evidence for the validation of MR imaging in the evaluation of this pathology in patients who have undergone diskectomy by retrospectively classifying their preoperative MRI. MATERIALS AND METHODS This retrospective, institutional review board-approved study included 54 of 86 consecutive patients (47 men; average age, 44 years) enrolled in an ongoing prospective trial of surgically treated lumbar disk herniation who had preoperative MRI and documented intraoperative classification of the abnormal disk as protrusion, extrusion, or sequestration by the treating surgeon. Preoperative MRI was classified by 2 blinded radiologists; discrepancies were resolved by a third reader. Statistical analysis of interobserver agreement and imaging compared with surgical findings was performed. RESULTS The readers disagreed on only 1 of the 54 cases. The third reader resolved the disagreement. Eight protrusions and 46 extrusions were found on imaging, with no sequestrations. At surgery, there were 13 protrusions and 40 extrusions, with 2 of the extrusions also containing sequestrations; the remaining case had only sequestration. There were 16 discrepancies between imaging and surgery, resulting in 70% agreement. CONCLUSIONS This study, which was intended to validate the multisociety combined task force definitions of abnormal disk morphology by using MR imaging with a surgical criterion standard, found 70% agreement between imaging diagnosis and surgical findings. Although reasonable, this finding highlights differences that often exist between intraoperative and preoperative imaging findings of lumbar disk herniation.
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Affiliation(s)
- C H Cho
- From the Departments of Radiology (C.H.C., L.H., A.A.Z.)
| | - L Hsu
- From the Departments of Radiology (C.H.C., L.H., A.A.Z.)
| | - M L Ferrone
- Orthopedic Surgery (M.L.F., D.A.L., M.B.H., C.M.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - D A Leonard
- Orthopedic Surgery (M.L.F., D.A.L., M.B.H., C.M.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - M B Harris
- Orthopedic Surgery (M.L.F., D.A.L., M.B.H., C.M.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - A A Zamani
- From the Departments of Radiology (C.H.C., L.H., A.A.Z.)
| | - C M Bono
- Orthopedic Surgery (M.L.F., D.A.L., M.B.H., C.M.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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20
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Corcoran AE, Richerson GB, Harris MB. Functional link between the hypocretin and serotonin systems in the neural control of breathing and central chemosensitivity. J Neurophysiol 2015; 114:381-9. [PMID: 25878157 DOI: 10.1152/jn.00870.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/09/2015] [Indexed: 11/22/2022] Open
Abstract
Serotonin (5-HT)-synthesizing neurons of the medullary raphe are putative central chemoreceptors, proposed to be one of potentially multiple brain stem chemosensitive cell types and loci interacting to produce the respiratory chemoreflex. Hypocretin-synthesizing neurons of the lateral hypothalamus are important contributors to arousal state, thermoregulation, and feeding behavior and are also reportedly involved in the hypercapnic ventilatory response. Recently, a functional interaction was found between the hypocretin system and 5-HT neurons of the dorsal raphe. The validity and potential significance of hypocretin modulation of medullary raphe 5-HT neurons, however, is unknown. As such, the purpose of this study was to explore functional interactions between the hypocretin system and 5-HT system of the medullary raphe on baseline respiratory output and central chemosensitivity. To explore such interactions, we used the neonatal in vitro medullary slice preparation derived from wild-type (WT) mice (normal 5-HT function) and a knockout strain lacking all central 5-HT neurons (Lmx1b(f/f/p) mice). We examined effects of acidosis, hypocretin-1, a hypocretin receptor antagonist (SB-408124), and the effect of the antagonist on the response to acidosis. We confirmed the critical role of 5-HT neurons in central chemosensitivity given that the increased hypoglossal burst frequency with acidosis, characteristic of WT mice, was absent in preparations derived from Lmx1b(f/f/p) mice. We also found that hypocretin facilitated baseline neural ventilatory output in part through 5-HT neurons. Although the impact of hypocretin on 5-HT neuronal sensitivity to acidosis is still unclear, hypocretins did appear to mediate the burst duration response to acidosis via serotonergic mechanisms.
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Affiliation(s)
- Andrea E Corcoran
- Department of Biology and Wildlife, and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska; Departments of Neurology and Cellular & Molecular Physiology, Yale University, New Haven, Connecticut; Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire;
| | - George B Richerson
- Departments of Neurology and Cellular & Molecular Physiology, Yale University, New Haven, Connecticut; Veteran's Affairs Medical Center, West Haven, Connecticut; and Departments of Neurology and Molecular Physiology & Biophysics, University of Iowa, Iowa City, Iowa
| | - Michael B Harris
- Department of Biology and Wildlife, and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska
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21
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Massey CA, Iceman KE, Johansen SL, Wu Y, Harris MB, Richerson GB. Isoflurane abolishes spontaneous firing of serotonin neurons and masks their pH/CO₂ chemosensitivity. J Neurophysiol 2015; 113:2879-88. [PMID: 25695656 DOI: 10.1152/jn.01073.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/18/2015] [Indexed: 11/22/2022] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) neurons from the mouse and rat rostral medulla are stimulated by increased CO2 when studied in culture or brain slices. However, the response of 5-HT neurons has been variable when animals are exposed to hypercapnia in vivo. Here we examined whether halogenated inhalational anesthetics, which activate TWIK-related acid-sensitive K(+) (TASK) channels, could mask an effect of CO2 on 5-HT neurons. During in vivo plethysmography in mice, isoflurane (1%) markedly reduced the hypercapnic ventilatory response (HCVR) by 78-96% depending upon mouse strain and ambient temperature. In a perfused rat brain stem preparation, isoflurane (1%) reduced or silenced spontaneous firing of medullary 5-HT neurons in situ and abolished their responses to elevated perfusate Pco2. In dissociated cell cultures, isoflurane (1%) hyperpolarized 5-HT neurons by 6.52 ± 3.94 mV and inhibited spontaneous firing. A subsequent decrease in pH from 7.4 to 7.2 depolarized neurons by 4.07 ± 2.10 mV, but that was insufficient to reach threshold for firing. Depolarizing current restored baseline firing and the firing frequency response to acidosis, indicating that isoflurane did not block the underlying mechanisms mediating chemosensitivity. These results demonstrate that isoflurane masks 5-HT neuron chemosensitivity in vitro and in situ and markedly decreases the HCVR in vivo. The use of this class of anesthetic has a particularly potent inhibitory effect on chemosensitivity of 5-HT neurons.
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Affiliation(s)
- Cory A Massey
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa Hospitals and Clinics, Iowa City, Iowa; Department of Neurology and NIH/NINDS Center for SUDEP Research, University of Iowa Hospitals and Clinics, Iowa City, Iowa;
| | - Kimberly E Iceman
- Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska
| | - Sara L Johansen
- Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska
| | - Yuanming Wu
- Department of Neurology and NIH/NINDS Center for SUDEP Research, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Michael B Harris
- Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska; Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska
| | - George B Richerson
- Department of Neurology and NIH/NINDS Center for SUDEP Research, University of Iowa Hospitals and Clinics, Iowa City, Iowa; Department of Molecular Physiology and Biophysics, University of Iowa Hospitals and Clinics, Iowa City, Iowa; and Department of Veterans Affairs Medical Center, Iowa City, Iowa
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22
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Abstract
Cognitive control mechanisms provide the flexibility to rapidly adapt to contextual demands. These contexts can be defined by top-down goals-but also by bottom-up perceptual factors, such as the location at which a visual stimulus appears. There are now several experiments reporting contextual control effects. Such experiments establish that contexts defined by low-level perceptual cues such as the location of a visual stimulus can lead to context-specific control, suggesting a relatively early focus for cognitive control. The current set of experiments involved a word-word interference task designed to assess whether a high-level cue, the semantic category to which a word belongs, can also facilitate contextual control. Indeed, participants exhibit a larger Flanker effect to items pertaining to a semantic category in which 75% of stimuli are incongruent than in response to items pertaining to a category in which 25% of stimuli are incongruent. Thus, both low-level and high-level stimulus features can affect the bottom-up engagement of cognitive control. The implications for current models of cognitive control are discussed.
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Affiliation(s)
- Chris Blais
- a Department of Psychology , Arizona State University , Tempe , AZ, USA
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23
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Mosher BP, Taylor BE, Harris MB. Intermittent hypercapnia enhances CO₂ responsiveness and overcomes serotonergic dysfunction. Respir Physiol Neurobiol 2014; 200:33-9. [PMID: 24874557 PMCID: PMC4167740 DOI: 10.1016/j.resp.2014.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 05/18/2014] [Accepted: 05/20/2014] [Indexed: 11/29/2022]
Abstract
Serotonergic dysfunction compromises ventilatory chemosensitivity and may enhance vulnerability to pathologies such as the Sudden Infant Death Syndrome (SIDS). We have shown raphé contributions to central chemosensitivity involving serotonin (5-HT)-and γ-aminobutyric acid (GABA)-mediated mechanisms. We tested the hypothesis that mild intermittent hypercapnia (IHc) induces respiratory plasticity, due in part to strengthening of GABA mechanisms. Rat pups were IHc-pretreated (eight consecutive cycles; 5 min 5% CO2 - air, 10 min air) or constant normocapnia-pretreated as a control, each day for 5 consecutive days beginning at P12. We subsequently assessed CO2 responsiveness using the in situ perfused brainstem preparation. Hypercapnic responses were determined with and without pharmacological manipulation. Results show IHc-pretreatment induces plasticity sufficient for responsiveness despite removal of otherwise critical ketanserin-sensitive mechanisms. Responsiveness following IHc-pretreatment was absent if ketanserin was combined with GABAergic antagonism, indicating that plasticity depends on GABAergic mechanisms. We propose that IHc-induced plasticity could reduce the severity of reflex dysfunctions underlying pathologies such as SIDS.
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Affiliation(s)
- Bryan P Mosher
- University of Alaska Fairbanks, Biology and Wildlife Department, Fairbanks, AK, United States
| | - Barbara E Taylor
- University of Alaska Fairbanks, Biology and Wildlife Department, Fairbanks, AK, United States; Institute of Arctic Biology, Fairbanks, AK, United States
| | - Michael B Harris
- University of Alaska Fairbanks, Biology and Wildlife Department, Fairbanks, AK, United States; Institute of Arctic Biology, Fairbanks, AK, United States.
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24
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Iceman KE, Corcoran AE, Taylor BE, Harris MB. CO2-inhibited neurons in the medullary raphé are GABAergic. Respir Physiol Neurobiol 2014; 203:28-34. [PMID: 25087734 DOI: 10.1016/j.resp.2014.07.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 07/24/2014] [Accepted: 07/24/2014] [Indexed: 11/28/2022]
Abstract
Previous studies have reported subsets of medullary raphé neurons that are either stimulated or inhibited by CO2/pH in vitro, in situ, and in vivo. We tested the hypothesis that medullary raphé CO2-inhibited neurons are GABAergic. Extracellular recordings in unanesthetized juvenile in situ rat preparations showed reversible hypercapnia-induced suppression of 19% (63/323) of medullary raphé neurons, and this suppression persisted after antagonism of NMDA, AMPA/kainate, and GABAA receptors. We stained a subset of CO2-inhibited cells and found that most (11/12) had glutamic acid decarboxylase 67 immunoreactivity (GAD67-ir). These data indicate that the majority of acidosis-inhibited medullary raphé neurons are GABAergic, and that their chemosensitivity is independent of major fast synaptic inputs. Thus, CO2-sensitive GABAergic neurons may play a role in central CO2/pH chemoreception.
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Affiliation(s)
- Kimberly E Iceman
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Andrea E Corcoran
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Barbara E Taylor
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Michael B Harris
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
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25
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Christian SL, Rasley BT, Roe T, Moore JT, Harris MB, Drew KL. Habituation of Arctic ground squirrels (Urocitellus parryii) to handling and movement during torpor to prevent artificial arousal. Front Physiol 2014; 5:174. [PMID: 24847278 PMCID: PMC4023073 DOI: 10.3389/fphys.2014.00174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/15/2014] [Indexed: 11/13/2022] Open
Abstract
Hibernation is a unique physiological adaptation characterized by periods of torpor that consist of repeated, reversible, and dramatic reductions of body temperature, metabolism, and blood flow. External and internal triggers can induce arousal from torpor in the hibernator. Studies of hibernating animals often require that animals be handled or moved prior to sampling or euthanasia but this movement can induce changes in the hibernation status of the animal. In fact, it has been demonstrated that movement of animals while they are hibernating is sufficient to induce an artificial arousal, which can detrimentally alter experimental findings obtained from animals assumed to be torpid. Therefore, we assessed a method to induce habituation of torpid hibernators to handling and movement to reduce inadvertent arousals. A platform rocker was used to mimic motion experienced during transfer of an animal and changes in respiratory rate (RR) were used to assess responsiveness of torpid Arctic ground squirrels (AGS, Urocitellus parryii). We found that movement alone did not induce a change in RR, however, exposure to handling induced an increase in RR in almost all AGS. This change in RR was markedly reduced with increased exposures, and all AGS exhibited a change in RR ≤ 1 by the end of the study. AGS habituated faster mid-season compared to early in the season, which mirrors other assessments of seasonal variation of torpor depth. However, AGS regained responsiveness when they were not exposed to daily handling. While AGS continued to undergo natural arousals during the study, occurrence of a full arousal was neither necessary for becoming habituated nor detrimental to the time required for habituation. These data suggest that even when torpid, AGS are able to undergo mechanosensory habituation, one of the simplest forms of learning, and provides a reliable way to reduce the sensitivity of torpid animals to handling.
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Affiliation(s)
- Sherri L Christian
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA ; Department of Biochemistry, Memorial University of Newfoundland St. John's, NL, Canada
| | - Brian T Rasley
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Tanna Roe
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Jeanette T Moore
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Michael B Harris
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Kelly L Drew
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
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26
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Abstract
Serotonin/substance P synthesizing cells in the raphé nuclei of the brain are candidates for designation as central chemoreceptors that are stimulated by CO2/pH. We have previously demonstrated that these neurons are CO2-stimulated in situ. Evidence also suggests that CO2-inhibited raphé neurons recorded in vitro and in situ synthesize GABA. Unknown is whether there are other types of chemosensitive cells in the raphé. Here, we showed that a previously unrecognized pool of raphé neurons also exhibit chemosensitivity, and that they are not serotonergic. We used extracellular recording of individual raphé neurons in the unanesthetized juvenile rat in situ perfused decerebrate brainstem preparation to assess chemosensitivity of raphé neurons. Subsequent juxtacellular labeling of individually recorded cells, and immunohistochemistry for the serotonin synthesizing enzyme tryptophan hydroxylase and for neurokinin-1 receptor (NK1R; the receptor for substance P) indicated a group of CO2-stimulated cells that are not serotonergic, but express NK1R and are closely apposed to surrounding serotonergic cells. CO2-stimulated 5-HT and non-5-HT cells constitute distinct groups that have different firing characteristics and hypercapnic sensitivities. Non-5-HT cells fire faster and are more robustly stimulated by CO2 than are 5-HT cells. Thus, we have characterized a previously unrecognized type of CO2-stimulated medullary raphé neuron that is not serotonergic, but may receive input from neighboring serotonin/substance P synthesizing chemosensitive neurons. The potential network properties of the three types of chemosensitive raphé neurons (the present non-5-HT cells, serotonergic cells, and CO2-inhibited cells) remain to be elucidated.
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Affiliation(s)
- K E Iceman
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA; Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA.
| | - M B Harris
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA; Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA
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27
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Abstract
Brainstem central chemoreceptors are critical to the hypercapnic ventilatory response, but their location and identity are poorly understood. When studied in vitro, serotonin-synthesizing (5-HT) neurons within the rat medullary raphé are intrinsically stimulated by CO2/acidosis. The contributions of these neurons to central chemosensitivity in vivo, however, are controversial. Lacking is documentation of CO2-sensitive 5-HT neurons in intact experimental preparations and understanding of their spatial and proportional distribution. Here we test the hypothesis that 5-HT neurons in the rat medullary raphé are sensitive to arterial hypercapnia. We use extracellular recording and hypercapnic challenge of spontaneously active medullary raphé neurons in the unanesthetized in situ perfused decerebrate brainstem preparation to assess chemosensitivity of individual cells. Juxtacellular labeling of a subset of recorded neurons and subsequent immunohistochemistry for the 5-HT-synthesizing enzyme tryptophan hydroxylase (TPH) identify or exclude this neurotransmitter phenotype in electrophysiologically characterized chemosensitive and insensitive cells. We show that the medullary raphé houses a heterogeneous population, including chemosensitive and insensitive 5-HT neurons. Of 124 recorded cells, 16 cells were juxtacellularly filled, visualized, and immunohistochemically identified as 5-HT synthesizing, based on TPH-immunoreactivity. Forty-four percent of 5-HT cells were CO2 stimulated (increased firing rate with hypercapnia), while 56% were unstimulated. Our results demonstrate that medullary raphé neurons are heterogeneous and clearly include a subset of 5-HT neurons that are excited by arterial hypercapnia. Together with data identifying intrinsically CO2-sensitive 5-HT neurons in vitro, these results support a role for such cells as central chemoreceptors in the intact system.
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Affiliation(s)
- Kimberly E Iceman
- Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska
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28
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Mosher BP, Taylor BE, Harris MB. Intermittent hypercapnia‐induced GABAergic plasticity sufficiently enhances ventilatory CO
2
/pH chemosensitivity to overcome serotonergic dysfunction. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1137.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Barbara E. Taylor
- Biology & WildlifeUniversity of Alaska FairbanksFairbanksAK
- Institute of Arctic BiologyFairbanksAK
| | - Michael B. Harris
- Biology & WildlifeUniversity of Alaska FairbanksFairbanksAK
- Institute of Arctic BiologyFairbanksAK
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29
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Hoffman M, Taylor BE, Harris MB. The origin of air breathing in vertebrates: turn (on) your head and cough. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1137.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Megan Hoffman
- Biology & WildlifeUniversity of Alaska FairbanksInstitute of Arctic BiologyFairbanksAK
| | - Barbara E. Taylor
- Biology & WildlifeUniversity of Alaska FairbanksInstitute of Arctic BiologyFairbanksAK
| | - Michael B. Harris
- Biology & WildlifeUniversity of Alaska FairbanksInstitute of Arctic BiologyFairbanksAK
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30
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Johansen SL, Iceman KE, Richerson GB, Harris MB. Isoflurane stimulates firing frequency and masks chemosensitivity of CO
2
‐inhibited GABAergic neurons
in situ. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1137.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Corcoran AE, Richerson GB, Harris MB. Serotonergic mechanisms are necessary for central respiratory chemoresponsiveness in situ. Respir Physiol Neurobiol 2013; 186:214-20. [PMID: 23454177 DOI: 10.1016/j.resp.2013.02.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
Evidence from in vivo and in vitro experiments conclude that serotonin (5-HT) neurons are involved in and play an important role in central respiratory CO2/H(+) chemosensitivity. This study was designed to assess the importance of 5-HT neurons and 5-HT receptor activation in the frequency and amplitude components of the hypercapnic response of the respiratory network in the unanesthetized perfused in situ juvenile rat brainstem preparation that exhibits patterns of phrenic nerve discharge similar to breathing in vivo. Exposure to a hypercapnic perfusate increased phrenic burst frequency and/or amplitude, the neural correlates of breathing frequency and tidal volume in vivo. Hypercapnic responses were also assessed during exposure to ketanserin (5-HT2 receptor antagonist), and 8-OH-DPAT (inhibiting 5-HT neurons via 5-HT1A autoreceptors). Neither of these drugs substantially altered baseline activity, however, both abolished hypercapnic responses of the respiratory network. These data illustrate that 5-HT neurons and 5-HT receptor activation are not required for respiratory rhythm generation per se, but are critical for CO2 responses in situ, supporting the hypothesis that 5-HT neurons play an important role in central ventilatory chemosensitivity in vivo.
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Affiliation(s)
- Andrea E Corcoran
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
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Abstract
Millions of people participate in pilgrimages around the world such as the Camino de Santiago. However, few studies have examined the effects of this type of activity on cardiovascular disease risk factors. The aim of this study is to evaluate changes in cardiovascular disease risk factors: c-reactive protein, cholesterol, triglycerides, blood pressure, and cardiorespiratory fitness levels following a 758 km, 30-day pilgrimage. 11 healthy male and female subjects between the ages of 18-56 participated in pre and post pilgrimage blood pressure and blood tests, as well as pre, during, and post pilgrimage weight, skin-fold, and aerobic fitness testing. Heart rate monitors and pedometers provided maximum, average, and minimum heart rates as well as distances covered during the exercise. The mean daily walking distance was 25 km at an average intensity of 55.96% (±1.93%) of maximum heart rate. Statistically significant changes were seen in body weight (79.3 kg±3.4 pre vs. 76.4±2.98 post, p<0.05), body fat percentage (24.48%±2.31% pre vs. 23.01%±2.12 post, p<0.05), systolic and diastolic blood pressure (119±3.82/75±2.73 pre vs. 110±5.07/69±3.10 post, p<0.05), as well as cardiorespiratory fitness. These data suggest that some cardiovascular disease risk factors can be improved in healthy subjects participating in a low intensity, long duration, high frequency activity such as a walking pilgrimage.
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Affiliation(s)
- M B Harris
- Kinesiology & Health Sciences, College of William and Mary, Williamsburg, USA.
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33
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Harris MB. Rat homologues to the human post-neonatal period: models for vulnerability to the sudden infant death syndrome. Pediatr Pulmonol 2012; 47:729-30; author reply 731. [PMID: 22162517 PMCID: PMC5218589 DOI: 10.1002/ppul.21605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 11/03/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Michael B. Harris
- Correspondence to: Michael B. Harris, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks, Rm. 311, Irving I, 902N Koyukuk Drive, Fairbanks, AK 99775-7000.
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Harris MB. Nontraditional case‐based instruction in physiology: Deconstructing the cryptophysiology of zombies. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.720.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael B Harris
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
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Iceman KE, Richerson GB, Harris MB. GABAergic neurons in the medullary raphé possess network independent chemosensitivity
in situ. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.894.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - George B. Richerson
- Departments of Neurology, and Molecular Physiology and BiophysicsUniversity of IowaIowa CityIA
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Abstract
Behaviour that is assumed to be guided by strategy can, in fact, be based on the implicit learning of regularities in the environment. We demonstrate this point in the context of a Stroop experiment. It has been shown previously that performance on this measure of cognitive control varies as a function of the relative proportions of congruent and incongruent trials in a block. Here we provide evidence that this modulation of performance is largely based on implicit, rather than explicit, knowledge of these proportions. This result has important implications for our understanding of cognitive control.
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Affiliation(s)
- Chris Blais
- University of California, Berkeley, Berkeley, CA, USA
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Blitzer D, Harris MB, Jackson EM. Affective Response And Pain Measurement Correlations In A 500 Mile Pilgrimage: El Camino De Santiago. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401437.12408.a4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Iceman KE, Corcoran AE, Harris MB. Raphe serotonin neurons: characteristics of central chemoreceptors in situ. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.1026.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Andrea E Corcoran
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
- PhysiologyDartmouth Medical SchoolLebanonNH
| | - Michael B Harris
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
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Corcoran AE, Richerson GB, Harris MB. Modulation of neuroventilation and central chemosensitivity: serotonergic and hypocretinergic effects. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.1026.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Michael B Harris
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
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40
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Hoffman M, Harris MB, Taylor BE. Characterization and validation of aerial respiration and central CO
2
chemosensitivity in the Alaska blackfish,
Dallia pectoralis. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.598.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Megan Hoffman
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
| | - Michael B Harris
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
| | - Barbara E Taylor
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
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Davies BL, Brundage CM, Harris MB, Taylor BE. Lung respiratory rhythm and pattern generation in the bullfrog: role of neurokinin-1 and mu-opioid receptors. J Comp Physiol B 2009; 179:579-92. [PMID: 19184042 DOI: 10.1007/s00360-009-0339-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 12/29/2008] [Accepted: 01/02/2009] [Indexed: 02/03/2023]
Abstract
Location of the lung respiratory rhythm generator (RRG) in the bullfrog brainstem was investigated by examining neurokinin-1 and mu-opioid receptor (NK1R, muOR) colocalization by immunohistochemistry and characterizing the role of these receptors in lung rhythm and episodic pattern generation. NK1R and muOR occurred in brainstems from all developmental stages. In juvenile bullfrogs a distinct area of colocalization was coincident with high-intensity fluorescent labeling of muOR; high-intensity labeling of muOR was not distinctly and consistently localized in tadpole brainstems. NK1R labeling intensity did not change with development. Similarity in colocalization is consistent with similarity in responses to substance P (SP, NK1R agonist) and DAMGO (muOR agonist) when bath applied to bullfrog brainstems of different developmental stages. In early stage tadpoles and juvenile bullfrogs, SP increased and DAMGO decreased lung burst frequency. In juvenile bullfrogs, SP increased lung burst frequency, episode frequency, but decreased number of lung bursts per episode and lung burst duration. In contrast, DAMGO decreased lung burst frequency and burst cycle frequency, episode frequency, and number of lung bursts per episode but increased all other lung burst parameters. Based on these results, we hypothesize that NK1R and muOR colocalization together with a metamorphosis-related increase in muOR intensity marks the location of the lung RRG but not necessarily the lung episodic pattern generator.
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Affiliation(s)
- B L Davies
- Institute of Arctic Biology, University of Alaska Fairbanks, Rm 311 Irving I, 902 N Koyukuk Drive, Fairbanks, AK 99775, USA
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Abstract
OBJECTIVES This project was developed to identify ways to support hospital-based improvements for the identification and management of osteoporosis following treatment of a fragility fracture. DESIGN This is a retrospective review of medical records of sets of consecutive patients who were admitted for surgical treatment of fragility fracture following introduction of several versions of admission and discharge care pathways. Effectiveness of the admission pathway was defined as % subjects with measurement of serum 25- hydroxyvitamin D (25(OH)D) during hospitalization; effectiveness of the discharge pathway was defined as % subjects with documentation of instructions for calcium and/or vitamin D supplementation. SETTING This study reviewed medical records of patients admitted to hospital for surgical treatment of a fragility fracture. PARTICIPANTS Medical records were evaluated for 98 patients older than 50-years who were admitted with a fragility fracture of the hip or femur. MEASUREMENTS Medical records were reviewed for the % subjects with documentation of an in-hospital order for serum 25(OH)D and with documentation of instructions to patients upon discharge concerning calcium and vitamin D intake. Median value of serum 25(OH)D was calculated. RESULTS In accordance with the admission pathway, serum 25(OH)D was measured in 37% (36/98). The median 25(OH)D level was 19.5 ng/mL; 78% were vitamin D insufficient [serum 25(OH)D < or = 32 ng/mL] and 58% were vitamin D deficient [serum 25(OH)D < or = 20 ng/mL]. In accordance with the discharge pathway, 74% (71/96) were discharged on calcium and/or vitamin D. CONCLUSION The high prevalence of vitamin D insufficiency (78%) observed in this study affirms the importance of incorporating vitamin D supplementation in hospital-based fracture care pathways. The discharge pathway was more effective than the newer admission pathway, a finding attributable to effects of familiarity, retraining, and introduction of computer-prompts. These evolving pathways represent a much-needed paradigm shift in the care of fragility fracture patients.
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Affiliation(s)
- J Glowacki
- Department of Orthopedic Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Hodges MR, Tattersall GJ, Harris MB, McEvoy SD, Richerson DN, Deneris ES, Johnson RL, Chen ZF, Richerson GB. Defects in breathing and thermoregulation in mice with near-complete absence of central serotonin neurons. J Neurosci 2008; 28:2495-505. [PMID: 18322094 PMCID: PMC6671195 DOI: 10.1523/jneurosci.4729-07.2008] [Citation(s) in RCA: 258] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 01/21/2008] [Accepted: 01/21/2008] [Indexed: 01/28/2023] Open
Abstract
Serotonergic neurons project widely throughout the CNS and modulate many different brain functions. Particularly important, but controversial, are the contributions of serotonin (5-HT) neurons to respiratory and thermoregulatory control. To better define the roles of 5-HT neurons in breathing and thermoregulation, we took advantage of a unique conditional knock-out mouse in which Lmx1b is genetically deleted in Pet1-expressing cells (Lmx1b(f/f/p)), resulting in near-complete absence of central 5-HT neurons. Here, we show that the hypercapnic ventilatory response in adult Lmx1b(f/f/p) mice was decreased by 50% compared with wild-type mice, whereas baseline ventilation and the hypoxic ventilatory response were normal. In addition, Lmx1b(f/f/p) mice rapidly became hypothermic when exposed to an ambient temperature of 4 degrees C, decreasing core temperature to 30 degrees C within 120 min. This failure of thermoregulation was caused by impaired shivering and nonshivering thermogenesis, whereas thermosensory perception and heat conservation were normal. Finally, intracerebroventricular infusion of 5-HT stimulated baseline ventilation, and rescued the blunted hypercapnic ventilatory response. These data identify a previously unrecognized role of 5-HT neurons in the CO(2) chemoreflex, whereby they enhance the response of the rest of the respiratory network to CO(2). We conclude that the proper function of the 5-HT system is particularly important under conditions of environmental stress and contributes significantly to the hypercapnic ventilatory response and thermoregulatory cold defense.
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Affiliation(s)
- Matthew R Hodges
- Department of Neurology, Yale University, New Haven, Connecticut 06520, USA.
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Corcoran AE, Richerson GB, Harris MB. Serotonin (5‐HT) facilitates ventilation via distinct 5HT2 and 5HT4 receptor‐mediated mechanisms in situ, in the arterially perfused rat brainstem preparation. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1172.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - George B Richerson
- Departments of Neurology and PhysiologyYale School of MedicineNew HavenCT
| | - Michael B Harris
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAK
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Nicholson HS, Kretschmar CS, Krailo M, Bernstein M, Kadota R, Fort D, Friedman H, Harris MB, Tedeschi-Blok N, Mazewski C, Sato J, Reaman GH. Phase 2 study of temozolomide in children and adolescents with recurrent central nervous system tumors: a report from the Children's Oncology Group. Cancer 2007; 110:1542-50. [PMID: 17705175 DOI: 10.1002/cncr.22961] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Effective chemotherapy is lacking for most types of central nervous system (CNS) tumors in children. Temozolomide, an agent with activity against adult brain tumors, was investigated in children and adolescents with recurrent CNS tumors. METHODS Temozolomide was administered orally as monthly 5-day courses at doses of 200 mg/m(2)/d (patients with no prior craniospinal irradiation [CSI]) or 180 mg/m(2)/d (prior CSI). Patients with a complete (CR) or partial (PR) response or stable disease (SD) could continue temozolomide for up to 12 cycles. RESULTS The cohort comprised 122 patients, including 113 with CNS tumors. Median age was 11 years (range, 1-23 years). Among 104 evaluable patients with CNS tumors, 5 PRs and 1 CR were observed. PRs occurred in 1 of 23 evaluable patients with high-grade astrocytoma, 1 of 21 with low-grade astrocytoma, and 3 of 25 with medulloblastoma/primitive neuroectodermal tumor (PNET). The CR occurred in an additional patient with medulloblastoma/PNET. No responses were observed in patients with ependymoma, brain-stem glioma, or other CNS tumors. Notably, 41% of patients with low-grade astrocytoma had SD through 12 courses. The most frequent toxicities were grade 3 or 4 neutropenia (19%) and thrombocytopenia (25%); nonhematologic toxicity was infrequent. CONCLUSIONS Although overall objective responses were limited, further exploration of temozolomide may be warranted in children with medulloblastoma and other PNETs, or in patients with low-grade astrocytoma, perhaps in a setting of less pretreatment than the patients in the current study, or in the context of multiagent therapy.
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Affiliation(s)
- H Stacy Nicholson
- Department of Pediatrics, Oregon Health Science & University, Portland, Oregon, USA.
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Wacker P, Land VJ, Camitta BM, Kurtzberg J, Pullen J, Harris MB, Shuster JJ. Allergic reactions to E. coli L-asparaginase do not affect outcome in childhood B-precursor acute lymphoblastic leukemia: a Children's Oncology Group Study. J Pediatr Hematol Oncol 2007; 29:627-32. [PMID: 17805038 DOI: 10.1097/mph.0b013e3181483df1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We describe the outcome of children with B-precursor acute lymphoblastic leukemia registered on Pediatric Oncology Group 8602 who switched to Erwinia asparaginase (ASP) due to an allergy to the Escherichia coli product. Between February 1986 and January 1991, children in complete remission after induction that included intramuscular E. coli ASP (6000 U/m2x6) were randomized for consolidation. One regimen included intensive weekly intramuscular E. coli ASP (25,000 U/m2/wkx24). In case of an allergic reaction to E. coli ASP, Erwinia ASP was substituted at the same dose and schedule. Of the 540 eligible patients, 408 switched to Erwinia ASP due to an allergic reaction. Allergic reactions were significantly associated with younger age, white race, and standard-risk acute lymphoblastic leukemia. Multivariate Cox analysis adjusting for these factors demonstrated no correlation between the switch per se or the timing of the switch and event-free survival.
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Affiliation(s)
- Pierre Wacker
- Hôpitaux Universitaires de Genève, Geneva, Switzerland
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Hoffman JM, Brown JW, Sirlin EA, Benoit AM, Gill WH, Harris MB, Darnall RA. Activation of 5-HT1A receptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet. Am J Physiol Regul Integr Comp Physiol 2007; 293:R518-27. [PMID: 17409258 DOI: 10.1152/ajpregu.00816.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of 5-HT1A receptors in the medullary raphé decreases sympathetic outflow to thermoregulatory mechanisms, including brown adipose tissue (BAT), thermogenesis, and peripheral vasoconstriction when these mechanisms are previously activated with leptin, prostaglandins, or cooling. These same mechanisms are also inhibited during rapid eye movement (REM) sleep. It is not known whether shivering is also modulated by medullary raphé neurons. We previously showed in the conscious piglet that activation of 5-HT1A receptors with 8-OH-DPAT (DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the midline raphé that contains 5-HT neurons, decreases heart rate, body temperature and muscle activity during non-rapid eye movement (NREM) sleep. We therefore hypothesized that activation of 5-HT1A receptors in the PGCL would also attenuate shivering and peripheral vasoconstriction during cooling. During REM sleep in a cool environment, shivering, carbon dioxide production, and body temperature decreased, and ear capillary blood flow and ear skin temperature increased. Shivering associated with rapid cooling was attenuated after dialysis of DPAT into the PGCL. In animals maintained in a continuously cool environment, dialysis of DPAT into the PGCL attenuated shivering and decreased body temperature, but there were no significant increases in ear capillary blood flow or ear skin temperature. We conclude that both naturally occurring REM sleep and exogenous activation of 5-HT1A receptors in the PGCL are associated with a suspension of shivering during cooling. Our data are consistent with the hypothesis that 5-HT neurons in the PGCL facilitate oscillating spinal motor circuits involved in shivering but are less involved in modulating sympathetically mediated thermoregulatory mechanisms.
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Affiliation(s)
- J M Hoffman
- Department of Physiology, Dartmouth Medical School, One Medical Center Drive, Lebanon, NH, USA
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Drew KL, Buck CL, Barnes BM, Christian SL, Rasley BT, Harris MB. Central nervous system regulation of mammalian hibernation: implications for metabolic suppression and ischemia tolerance. J Neurochem 2007; 102:1713-1726. [PMID: 17555547 PMCID: PMC3600610 DOI: 10.1111/j.1471-4159.2007.04675.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Torpor during hibernation defines the nadir of mammalian metabolism where whole animal rates of metabolism are decreased to as low as 2% of basal metabolic rate. This capacity to decrease profoundly the metabolic demand of organs and tissues has the potential to translate into novel therapies for the treatment of ischemia associated with stroke, cardiac arrest or trauma where delivery of oxygen and nutrients fails to meet demand. If metabolic demand could be arrested in a regulated way, cell and tissue injury could be attenuated. Metabolic suppression achieved during hibernation is regulated, in part, by the central nervous system through indirect and possibly direct means. In this study, we review recent evidence for mechanisms of central nervous system control of torpor in hibernating rodents including evidence of a permissive, hibernation protein complex, a role for A1 adenosine receptors, mu opiate receptors, glutamate and thyrotropin-releasing hormone. Central sites for regulation of torpor include the hippocampus, hypothalamus and nuclei of the autonomic nervous system. In addition, we discuss evidence that hibernation phenotypes can be translated to non-hibernating species by H(2)S and 3-iodothyronamine with the caveat that the hypothermia, bradycardia, and metabolic suppression induced by these compounds may or may not be identical to mechanisms employed in true hibernation.
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Affiliation(s)
- Kelly L. Drew
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - C. Loren Buck
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA
| | - Brian M. Barnes
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Sherri L. Christian
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Brian T. Rasley
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Michael B. Harris
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
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Toppin VAL, Harris MB, Kober AM, Leiter JC, St-John WM. Persistence of eupnea and gasping following blockade of both serotonin type 1 and 2 receptors in the in situ juvenile rat preparation. J Appl Physiol (1985) 2007; 103:220-7. [PMID: 17412795 DOI: 10.1152/japplphysiol.00071.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In severe hypoxia or ischemia, normal eupneic breathing is replaced by gasping, which can serve as a powerful mechanism for "autoresuscitation." We have proposed that gasping is generated by medullary neurons having intrinsic pacemaker bursting properties dependent on a persistent sodium current. A number of neuromodulators, including serotonin, influence persistent sodium currents. Thus we hypothesized that endogenous serotonin is essential for gasping to be generated. To assess such a critical role for serotonin, a preparation of the perfused, juvenile in situ rat was used. Activities of the phrenic, hypoglossal, and vagal nerves were recorded. We added blockers of type 1 and/or type 2 classes of serotonergic receptors to the perfusate delivered to the preparation. Eupnea continued following additions of any of the blockers. Changes were limited to an increase in the frequency of phrenic bursts and a decline in peak heights of all neural activities. In ischemia, gasping was induced following any of the blockers. Few statistically significant changes in parameters of gasping were found. We thus did not find a differential suppression of gasping, compared with eupnea, following blockers of serotonin receptors. Such a differential suppression had been proposed based on findings using an in vitro preparation. We hypothesize that multiple neurotransmitters/neuromodulators influence medullary mechanisms underlying the neurogenesis of gasping. In greatly reduced in vitro preparations, the importance of any individual neuromodulator, such as serotonin, may be exaggerated compared with its role in more intact preparations.
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Abstract
AIM Nitric oxide (NO) plays an important role in the transition from intrauterine to extrauterine life. If this transition fails, a condition called persistent pulmonary hypertension of the neonate (PPHN) may develop. The current treatment modalities for this disease include induction of alkalosis by hyperventilation or alkali infusion, inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation. There is evidence from animal studies that the elevated pH, not the low pCO2 is responsible for the resultant pulmonary vasodilatation. In this study, we examined the effect of pH on the activity and expression of endothelial nitric oxide synthase (eNOS) in cultured bovine aortic endothelial cells (BAEC) as a possible explanation for the pH dependent drop in pulmonary vascular resistance. METHODS BAEC were exposed to a pH gradient of 7.1-7.6 for 4 h (short-term) and 16 h (long-term). Standard Western blotting technique was used to detect expression of eNOS. Activity was measured by an indirect assay using bovine aortic smooth muscle cells (BASM) as reporter cells and measuring cGMP levels as a marker of NO production. The cells were exposed to the pH gradient for a total of 4 h and measurement were made at 30, 60 and 90 min, and 2, 3 and 4 hours. RESULTS eNOS activity and expression remained unchanged during the four and sixteen hours of exposure. CONCLUSION In this in vitro experiment, we could not demonstrate an alkalosis-induced increase in eNOS activity and expression. The clinically observed pH dependent vasodilatation does not appear to be directly mediated through the induction of eNOS.
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Affiliation(s)
- Sandor Nagy
- Section of Neonatology, Medical College of Georgia, Augusta, Georgia 30912-3740, USA
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