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Marguerite NT, Bernard J, Harrison DA, Harris D, Cooper RL. Effect of Temperature on Heart Rate for Phaenicia sericata and Drosophila melanogaster with Altered Expression of the TrpA1 Receptors. INSECTS 2021; 12:38. [PMID: 33418937 PMCID: PMC7825143 DOI: 10.3390/insects12010038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 12/24/2020] [Accepted: 01/02/2021] [Indexed: 11/29/2022]
Abstract
The transient receptor potential (TrpA-ankyrin) receptor has been linked to pathological conditions in cardiac function in mammals. To better understand the function of the TrpA1 in regulation of the heart, a Drosophila melanogaster model was used to express TrpA1 in heart and body wall muscles. Heartbeat of in intact larvae as well as hearts in situ, devoid of hormonal and neural input, indicate that strong over-expression of TrpA1 in larvae at 30 or 37 °C stopped the heart from beating, but in a diastolic state. Cardiac function recovered upon cooling after short exposure to high temperature. Parental control larvae (UAS-TrpA1) increased heart rate transiently at 30 and 37 °C but slowed at 37 °C within 3 min for in-situ preparations, while in-vivo larvae maintained a constant heart rate. The in-situ preparations maintained an elevated rate at 30 °C. The heartbeat in the TrpA1-expressing strains could not be revived at 37 °C with serotonin. Thus, TrpA1 activation may have allowed enough Ca2+ influx to activate K(Ca) channels into a form of diastolic stasis. TrpA1 activation in body wall muscle confirmed a depolarization of membrane. In contrast, blowfly Phaenicia sericata larvae increased heartbeat at 30 and 37 °C, demonstrating greater cardiac thermotolerance.
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Affiliation(s)
- Nicole T. Marguerite
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA; (N.T.M.); (J.B.); (D.A.H.)
| | - Jate Bernard
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA; (N.T.M.); (J.B.); (D.A.H.)
| | - Douglas A. Harrison
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA; (N.T.M.); (J.B.); (D.A.H.)
| | | | - Robin L. Cooper
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA; (N.T.M.); (J.B.); (D.A.H.)
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Bernard J, Marguerite N, Inks M, L. Cooper R. Assessment of Bacterial Endotoxin Lipopolysaccharide (LPS) Potential Interaction and TRPA1 Thermal Receptors on Synaptic Transmission. ACTA ACUST UNITED AC 2019. [DOI: 10.3923/crb.2020.10.21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ballinger- C, Anyagaligb O, Bernard J, Bierbower SM, Dupont-Ver EE, Ghoweri A, Greenhalgh A, Harrison D, Istas O, McNabb M, Saelinger C, Stanback A, Stanback M, Thibault O, Cooper RL. Effects of Bacterial Endotoxin (LPS) on Cardiac and Synaptic Function in Various Animal Models: Larval Drosophila, Crayfish, Crab and Rodent. ACTA ACUST UNITED AC 2019. [DOI: 10.3923/ijzr.2020.33.62] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Potter S, Sifers J, Yocom E, Blümich SLE, Potter R, Nadolski J, Harrison DA, Cooper RL. Effects of inhibiting mTOR with rapamycin on behavior, development, neuromuscular physiology and cardiac function in larval Drosophila. Biol Open 2019; 8:bio.046508. [PMID: 31704693 PMCID: PMC6899040 DOI: 10.1242/bio.046508] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Rapamycin and other mTOR inhibitors are being heralded as possible treatments for many human ailments. It is currently being utilized clinically as an immunomodulator after transplantation procedures and as a treatment for certain forms of cancer, but it has numerous potential clinical indications. Some studies have shown profound effects on life cycle and muscle physiology, but these issues have not been addressed in an organism undergoing developmental processes. This paper fills this void by examining the effect of mTOR inhibition by rapamycin on several different qualities of larval Drosophila. Various dosages of the compound were fed to second instar larvae. These larvae were monitored for pupae formation to elucidate possible life cycle effects, and a delay to pupation was quantified. Behavioral deficits were documented in rapamycin-treated larvae. Electrophysiological measurements were taken to discern changes in muscle physiology and synaptic signaling (i.e. resting membrane potential, amplitude of excitatory post-synaptic potentials, synaptic facilitation). Pupation delay and effects on behavior that are likely due to synaptic alterations within the central nervous system were discovered in rapamycin-fed larvae. These results allow for several conclusions as to how mTOR inhibition by rapamycin affects a developing organism. This could eventually allow for a more informed decision when using rapamycin and other mTOR inhibitors to treat human diseases, especially in children and adolescents, to account for known side effects. Summary: Inhibiting mTOR by rapamycin delays pupation, reduced body wall contractions and mouth-hook movements while synaptic transmission appeared normal in larval Drosophila.
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Affiliation(s)
- Samuel Potter
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Jacob Sifers
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA.,Alice Lloyd College, 100 Purpose Road, Pippa Passes, KY, 41844, USA
| | - Emily Yocom
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA.,Kentucky Wesleyan College, Owensboro, KY, 42301, USA
| | - Sandra L E Blümich
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA.,Veterinärmedizinische Fakultät, Universität Leipzig, Leipzig, Germany
| | - Rachel Potter
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Jeremy Nadolski
- Department of Mathematical and Computational Sciences, Benedictine University, Lisle, IL, 60532 , USA
| | - Douglas A Harrison
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Robin L Cooper
- Deptartment of Biology and Center for Muscle Biology, University of Kentucky, Lexington, KY, 40506, USA
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Stanley CE, Mauss AS, Borst A, Cooper RL. The Effects of Chloride Flux on Drosophila Heart Rate. Methods Protoc 2019; 2:mps2030073. [PMID: 31443492 PMCID: PMC6789470 DOI: 10.3390/mps2030073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 11/16/2022] Open
Abstract
Approaches are sought after to regulate ionotropic and chronotropic properties of the mammalian heart. Electrodes are commonly used for rapidly exciting cardiac tissue and resetting abnormal pacing. With the advent of optogenetics and the use of tissue-specific expression of light-activated channels, cardiac cells cannot only be excited but also inhibited with ion-selective conductance. As a proof of concept for the ability to slow down cardiac pacing, anion-conducting channelrhodopsins (GtACR1/2) and the anion pump halorhodopsin (eNpHR) were expressed in hearts of larval Drosophila and activated by light. Unlike body wall muscles in most animals, the equilibrium potential for Cl− is more positive as compared to the resting membrane potential in larval Drosophila. As a consequence, upon activating the two forms of GtACR1 and 2 with low light intensity the heart rate increased, likely due to depolarization and opening of voltage-gated Ca2+ channels. However, with very intense light activation the heart rate ceases, which may be due to Cl– shunting to the reversal potential for chloride. Activating eNpHR hyperpolarizes body wall and cardiac muscle in larval Drosophila and rapidly decreases heart rate. The decrease in heart rate is related to light intensity. Intense light activation of eNpHR stops the heart from beating, whereas lower intensities slowed the rate. Even with upregulation of the heart rate with serotonin, the pacing of the heart was slowed with light. Thus, regulation of the heart rate in Drosophila can be accomplished by activating anion-conducting channelrhodopsins using light. These approaches are demonstrated in a genetically amenable insect model.
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Affiliation(s)
- Catherine E Stanley
- Department of Biology, Center for Muscle Biology. University of Kentucky, Lexington, KY 40506-0225, USA
| | - Alex S Mauss
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Alexander Borst
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Robin L Cooper
- Department of Biology, Center for Muscle Biology. University of Kentucky, Lexington, KY 40506-0225, USA.
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Istas O, Greenhalgh A, Cooper R. The Effects of a Bacterial Endotoxin on Behavior and Sensory-CNS-Motor Circuits in Drosophila melanogaster. INSECTS 2019; 10:insects10040115. [PMID: 31013568 PMCID: PMC6523965 DOI: 10.3390/insects10040115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 02/06/2023]
Abstract
The effect of bacterial sepsis on animal behavior and physiology is complex due to direct and indirect actions. The most common form of bacterial sepsis in humans is from gram-negative bacterial strains. The endotoxin (lipopolysaccharide, LPS) and/or associated peptidoglycans from the bacteria are the key agents to induce an immune response, which then produces a cascade of immunological consequences. However, there are direct actions of LPS and associated peptidoglycans on cells which are commonly overlooked. This study showed behavioral and neural changes in larval Drosophila fed commercially obtained LPS from Serratia marcescens. Locomotor behavior was not altered, but feeding behavior increased and responses to sensory tactile stimuli were decreased. In driving a sensory-central nervous system (CNS)-motor neural circuit in in-situ preparations, direct application of commercially obtained LPS initially increased evoked activity and then decreased and even stopped evoked responses in a dose-dependent manner. With acute LPS and associated peptidoglycans exposure (10 min), the depressed neural responses recovered within a few minutes after removal of LPS. Commercially obtained LPS induces a transitory hyperpolarization of the body wall muscles within seconds of exposure and alters activity within the CNS circuit. Thus, LPS and/or associated peptidoglycans have direct effects on body wall muscle without a secondary immune response.
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Affiliation(s)
- Oscar Istas
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| | - Abigail Greenhalgh
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| | - Robin Cooper
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
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