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Vacassenno RM, Haddad CN, Cooper RL. Bacterial lipopolysaccharide hyperpolarizes the membrane potential and is antagonized by the K2p channel blocker doxapram. Comp Biochem Physiol C Toxicol Pharmacol 2023; 266:109571. [PMID: 36740004 DOI: 10.1016/j.cbpc.2023.109571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/14/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
Exposure of Drosophila skeletal muscle to bacterial lipopolysaccharides (LPS) rapidly and transiently hyperpolarizes membrane potential. However, the mechanism responsible for hyperpolarization remains unclear. The resting membrane potential of the cells is maintained through multiple mechanisms. This study investigated the possibility of LPS activating calcium-activated potassium channels (KCa) and/or K2p channels. 2-Aminoethyl diphenylborinate (2-APB), blocks uptake of Ca2+ into the endoplasmic reticulum (ER); thus, limiting release from ryanodine-sensitive internal stores to reduce the function of KCa channels. Exposure to 2-APB produces waves of hyperpolarization even during desensitization of the response to LPS and in the presence of doxapram. This finding in this study suggests that doxapram blocked the acid-sensitive K2p tandem-pore channel subtype known in mammals. Doxapram blocked LPS-induced hyperpolarization and depolarized the muscles as well as induced motor neurons to produce evoked excitatory junction potentials (EJPs). This was induced by depolarizing motor neurons, similar to the increase in extracellular K+ concentration. The hyperpolarizing effect of LPS was not blocked by decreased extracellular Ca2+or the presence of Cd2+. LPS appears to transiently activate doxapram sensitive K2p channels independently of KCa channels in hyperpolarizing the muscle. Septicemia induced by gram-negative bacteria results in an increase in inflammatory cytokines, primarily induced by bacterial LPS. Currently, blockers of LPS receptors in mammals are unknown; further research on doxapram and other K2p channels is warranted. (220 words).
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Affiliation(s)
- Rachael M Vacassenno
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA; Department of Biology, Eastern Kentucky University, Richmond, KY 40475, USA.
| | - Christine N Haddad
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
| | - Robin L Cooper
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
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Cressman A, Amsalem E. Impacts and mechanisms of CO2 narcosis in bumble bees: narcosis depends on dose, caste and mating status and is not induced by anoxia. J Exp Biol 2023; 226:286149. [PMID: 36541091 DOI: 10.1242/jeb.244746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
Carbon dioxide (CO2) is commonly used to immobilize insects and to induce reproduction in bees. However, despite its wide use and potential off-target impacts, its underlying mechanisms are not fully understood. Here, we used Bombus impatiens to examine whether CO2 impacts are mediated by anoxia and whether these mechanisms differ between female castes or following mating in queens. We examined the behavior, physiology and gene expression of workers, mated queens and virgin queens following exposure to anoxia, hypoxia, full and partial hypercapnia, and controls. Hypercapnia and anoxia caused immobilization, but only hypercapnia resulted in behavioral, physiological and molecular impacts in bees. Recovery from hypercapnia resulted in increased abdominal contractions and took longer in queens. Additionally, hypercapnia activated the ovaries of queens, but inhibited those of workers in a dose-dependent manner and caused a depletion of fat-body lipids in both castes. All responses to hypercapnia were weaker following mating in queens. Analysis of gene expression related to hypoxia and hypercapnia supported the physiological findings in queens, demonstrating that the overall impacts of CO2, excluding virgin queen ovaries, were unique and were not induced by anoxia. This study contributes to our understanding of the impacts and the mechanistic basis of CO2 narcosis in insects and its impacts on bee physiology. This article has an associated ECR Spotlight interview with Anna Cressman.
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Affiliation(s)
- Anna Cressman
- Department of Entomology, Center for Chemical Ecology, Center for Pollination Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Etya Amsalem
- Department of Entomology, Center for Chemical Ecology, Center for Pollination Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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3
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Mackowetzky K, Yoon KH, Mackowetzky EJ, Waskiewicz AJ. Development and evolution of the vestibular apparatuses of the inner ear. J Anat 2021; 239:801-828. [PMID: 34047378 PMCID: PMC8450482 DOI: 10.1111/joa.13459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/07/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022] Open
Abstract
The vertebrate inner ear is a labyrinthine sensory organ responsible for perceiving sound and body motion. While a great deal of research has been invested in understanding the auditory system, a growing body of work has begun to delineate the complex developmental program behind the apparatuses of the inner ear involved with vestibular function. These animal studies have helped identify genes involved in inner ear development and model syndromes known to include vestibular dysfunction, paving the way for generating treatments for people suffering from these disorders. This review will provide an overview of known inner ear anatomy and function and summarize the exciting discoveries behind inner ear development and the evolution of its vestibular apparatuses.
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Affiliation(s)
- Kacey Mackowetzky
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Kevin H. Yoon
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Andrew J. Waskiewicz
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
- Women & Children’s Health Research InstituteUniversity of AlbertaEdmontonAlbertaCanada
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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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Effects of bacterial endotoxin on regulation of the heart, a sensory-CNS-motor nerve circuit and neuromuscular junctions: Crustacean model. Comp Biochem Physiol A Mol Integr Physiol 2019; 237:110557. [DOI: 10.1016/j.cbpa.2019.110557] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/22/2019] [Accepted: 08/20/2019] [Indexed: 01/12/2023]
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Eatock RA. Specializations for Fast Signaling in the Amniote Vestibular Inner Ear. Integr Comp Biol 2019; 58:341-350. [PMID: 29920589 DOI: 10.1093/icb/icy069] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During rapid locomotion, the vestibular inner ear provides head-motion signals that stabilize posture, gaze, and heading. Afferent nerve fibers from central and peripheral zones of vestibular sensory epithelia use temporal and rate encoding, respectively, to emphasize different aspects of head motion: central afferents adapt faster to sustained head position and favor higher stimulus frequencies, reflecting specializations at each stage from motion of the accessory structure to spike propagation to the brain. One specialization in amniotes is an unusual nonquantal synaptic mechanism by which type I hair cells transmit to large calyceal terminals of afferent neurons. The reduced synaptic delay of this mechanism may have evolved to serve reliable and fast input to reflex pathways that ensure stable locomotion on land.
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Affiliation(s)
- Ruth Anne Eatock
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
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Poinapen D, Konopka JK, Umoh JU, Norley CJD, McNeil JN, Holdsworth DW. Micro-CT imaging of live insects using carbon dioxide gas-induced hypoxia as anesthetic with minimal impact on certain subsequent life history traits. BMC ZOOL 2017. [DOI: 10.1186/s40850-017-0018-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Martrette JM, Egloff C, Clément C, Yasukawa K, Thornton SN, Trabalon M. Effects of prolonged exposure to CO 2 on behaviour, hormone secretion and respiratory muscles in young female rats. Physiol Behav 2017; 177:257-262. [PMID: 28501558 DOI: 10.1016/j.physbeh.2017.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/07/2017] [Accepted: 05/04/2017] [Indexed: 11/28/2022]
Abstract
Atmospheric CO2 concentrations increased significantly over the last century and continuing increases are expected to have significant effects on current ecosystems. This study evaluated the behavioural and physiological (hormone status, muscle structure) effects of prolonged CO2 exposure in young female Wistar rats exposed at 700ppm of CO2 during 6h a day for 15days. Prolonged CO2 exposure, though not continuous, produced significant disturbances in behaviour with an increase in drinking, grooming and resting, and a reduction in rearing, jumping-play and locomotor activity. Furthermore, CO2 exposure was accompanied by increased plasma levels of corticosterone, suggesting that prolonged exposure to CO2 was stressful. The muscular structure can also be modified also when respiratory working conditions change. The expression of myosin heavy chain was significantly affected in the diaphragm and oral respiratory muscles: Masseter Superficialis and Anterior Digastric. Modified behaviour and hormonal changes both appear to be at the origin of the observed muscular adaptation.
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Affiliation(s)
- J M Martrette
- EA 3450 DevAH, Université de Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - C Egloff
- UMR 7039 CNRS, Université de Lorraine, 54505 Vandœuvre-lès-Nancy, France.
| | - C Clément
- EA 3450 DevAH, Université de Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - K Yasukawa
- EA 3450 DevAH, Université de Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - S N Thornton
- INSERM U_1116, Université de Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - M Trabalon
- UMR 6552 CNRS, Université de Rennes 1, 35042 Rennes, France
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Fregin T, Bickmeyer U. Electrophysiological Investigation of Different Methods of Anesthesia in Lobster and Crayfish. PLoS One 2016; 11:e0162894. [PMID: 27642755 PMCID: PMC5028027 DOI: 10.1371/journal.pone.0162894] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/30/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES In search for methods of anesthesia of crustaceans, an implanted electrode into lobster and crayfish CNS enabled us to monitor signal propagation in the nerve system of animals undergoing different protocols. RESULTS Cooling (tap water 0°C, sea water -1,8°C) and anesthesia with MgCl2 (10%) were both discarded as anesthetic procedures because responses to external stimuli were still detectable under treatment. Contrarily, bubbling the aquarium water with CO2 can be considered a "partially successful" anesthesia, because signal propagation is inhibited but before that the animals show discomfort. The procedure of "electro-stunning" induces epileptic-form seizures in the crustacean CNS (lobster, crayfish), which overlay but do not mitigate the response to external stimuli. After several minutes the activity declines before the nervous system starts to recover. A feasible way to sacrifice lobsters is to slowly raise the water temperature (1°C min-1), as all electrical activities in the CNS cease at temperatures above ~30°C, whereas below this temperature the animals do not show signs of stress or escape behavior (e.g. tail flips) in the warming water. CONCLUSION CO2 is efficient to anaesthetize lobster and crayfish but due to low pH in water is stressful to the animals previous to anesthesia. Electrical stunning induces epileptiform seizures but paralyses the animals and leads to a reversible decline of nerve system activity after seizure. Electric stunning or slowly warming just before preparation may meet ethical expectations regarding anaesthesia and to sacrifice crustaceans.
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Affiliation(s)
- Torsten Fregin
- Alfred Wegener Institut – Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Ulf Bickmeyer
- Alfred Wegener Institut – Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany
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Impaired climbing and flight behaviour in Drosophila melanogaster following carbon dioxide anaesthesia. Sci Rep 2015; 5:15298. [PMID: 26477397 PMCID: PMC4609961 DOI: 10.1038/srep15298] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 09/22/2015] [Indexed: 12/24/2022] Open
Abstract
Laboratories that study Drosophila melanogaster or other insects commonly use carbon dioxide (CO2) anaesthesia for sorting or other work. Unfortunately, the use of CO2 has potential unwanted physiological effects, including altered respiratory and muscle physiology, which impact motor function behaviours. The effects of CO2 at different levels and exposure times were examined on the subsequent recovery of motor function as assessed by climbing and flight assays. With as little as a five minute exposure to 100% CO2, D. melanogaster exhibited climbing deficits up to 24 hours after exposure. Any exposure length over five minutes produced climbing deficits that lasted for days. Flight behaviour was also impaired following CO2 exposure. Overall, there was a positive correlation between CO2 exposure length and recovery time for both behaviours. Furthermore, exposure to as little as 65% CO2 affected the motor capability of D. melanogaster. These negative effects are due to both a CO2-specific mechanism and an anoxic effect. These results indicate a heretofore unconsidered impact of CO2 anaesthesia on subsequent behavioural tests revealing the importance of monitoring and accounting for CO2 exposure when performing physiological or behavioural studies in insects.
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Majeed ZR, Ritter K, Robinson J, Blümich SLE, Brailoiu E, Cooper RL. New insights into the acute actions from a high dosage of fluoxetine on neuronal and cardiac function: Drosophila, crayfish and rodent models. Comp Biochem Physiol C Toxicol Pharmacol 2015; 176-177:52-61. [PMID: 26232582 DOI: 10.1016/j.cbpc.2015.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 07/22/2015] [Accepted: 07/23/2015] [Indexed: 12/31/2022]
Abstract
The commonly used mood altering drug fluoxetine (Prozac) in humans has a low occurrence in reports of harmful effects from overdose; however, individuals with altered metabolism of the drug and accidental overdose have led to critical conditions and even death. We addressed direct actions of high concentrations on synaptic transmission at neuromuscular junctions (NMJs), neural properties, and cardiac function unrelated to fluoxetine's action as a selective 5-HT reuptake inhibitor. There appears to be action in blocking action potentials in crayfish axons, enhanced occurrences of spontaneous synaptic vesicle fusion events in the presynaptic terminals at NMJs of both Drosophila and crayfish. In rodent neurons, cytoplasmic Ca(2+) rises by fluoxetine and is thapsigargin dependent. The Drosophila larval heart showed a dose dependent effect in cardiac arrest. Acute paralytic behavior in crayfish occurred at a systemic concentration of 2mM. A high percentage of death as well as slowed development occurred in Drosophila larvae consuming food containing 100μM fluoxetine. The release of Ca(2+) from the endoplasmic reticulum in neurons and the cardiac tissue as well as blockage of voltage-gated Na(+) channels in neurons could explain the effects on the whole animal as well as the isolated tissues. The use of various animal models in demonstrating the potential mechanisms for the toxic effects with high doses of fluoxetine maybe beneficial for acute treatments in humans. Future studies in determining how fluoxetine is internalized in cells and if there are subtle effects of these mentioned mechanisms presented with chronic therapeutic doses are of general interest.
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Affiliation(s)
- Zana R Majeed
- Department of Biology, University of Kentucky, USA; Lexington, KY, USA; Department of Biology, University of Salahaddin, Erbil, Iraq
| | - Kyle Ritter
- Department of Biology, University of Kentucky, USA; Lexington, KY, USA; Centre College, Danville, KY, USA
| | - Jonathan Robinson
- Department of Biology, University of Kentucky, USA; Lexington, KY, USA; Morehead State University, Morehead, KY, USA
| | - Sandra L E Blümich
- Department of Biology, University of Kentucky, USA; Lexington, KY, USA; V.M.F., University of Leipzig, Leipzig, Germany
| | | | - Robin L Cooper
- Department of Biology, University of Kentucky, USA; Lexington, KY, USA.
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Cadmium increases the sensitivity of adolescent female mice to nicotine-related behavioral deficits. Behav Neurol 2014; 2014:360978. [PMID: 25477708 PMCID: PMC4247978 DOI: 10.1155/2014/360978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 10/22/2014] [Indexed: 11/29/2022] Open
Abstract
This study investigates spatial and nonspatial working memory, anxiety related behavior, and motor activities in cadmium and/or nicotine exposed female adolescent mice. P28 female adolescent mice (albino strain) were divided into four groups of five (n = 5) mice each. A set of mice (Nic) received subcutaneous nicotine (2.0 mg/kg) while a separate set (Cd) was treated with 2.0 mg/kg cadmium (subcutaneous). For the combined treatments of cadmium and nicotine, we administered 2.0 mg/kg Nicotine and 2.0 mg/kg of Cd. Subsequently, a separate group of animals (n = 5; control) received normal saline. The total duration of treatment for all groups was 28 days (P28–P56). At P56, the treatment was discontinued, after which the animals were examined in behavioural tests. Nicotine and cadmium increased the metabolism and food intake in the female adolescent mice. This also corresponded to an increase in weight when compared with the control. However, a combined nicotine-cadmium treatment induced a decline in weight of the animals versus the control. Also, nicotine administration increased the motor function, while cadmium and nicotine-cadmium treatment caused a decline in motor activity. Both nicotine and cadmium induced a reduction in memory index; however, nicotine-cadmium treatment induced the most significant decrease in nonspatial working memory.
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Nicotine-Cadmium Interaction Alters Exploratory Motor Function and Increased Anxiety in Adult Male Mice. JOURNAL OF NEURODEGENERATIVE DISEASES 2014; 2014:359436. [PMID: 26317007 PMCID: PMC4437340 DOI: 10.1155/2014/359436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 08/27/2014] [Indexed: 12/05/2022]
Abstract
In this study we evaluated the time dependence in cadmium-nicotine interaction and its effect on motor function, anxiety linked behavioural changes, serum electrolytes, and weight after acute and chronic treatment in adult male mice. Animals were separated randomly into four groups of n = 6 animals each. Treatment was done with nicotine, cadmium, or nicotine-cadmium for 21 days. A fourth group received normal saline for the same duration (control). Average weight was determined at 7-day interval for the acute (D1-D7) and chronic (D7-D21) treatment phases. Similarly, the behavioural tests for exploratory motor function (open field test) and anxiety were evaluated. Serum electrolytes were measured after the chronic phase. Nicotine, cadmium, and nicotine-cadmium treatments caused no significant change in body weight after the acute phase while cadmium-nicotine and cadmium caused a decline in weight after the chronic phase. This suggests the role of cadmium in the weight loss observed in tobacco smoke users. Both nicotine and cadmium raised serum Ca2+ concentration and had no significant effect on K+ ion when compared with the control. In addition, nicotine-cadmium treatment increased bioaccumulation of Cd2+ in the serum which corresponded to a decrease in body weight, motor function, and an increase in anxiety.
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Majeed ZR, Titlow J, Hartman HB, Cooper R. Proprioception and tension receptors in crab limbs: student laboratory exercises. J Vis Exp 2013:e51050. [PMID: 24192613 PMCID: PMC3963413 DOI: 10.3791/51050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The primary purpose of these procedures is to demonstrate for teaching and research purposes how to record the activity of living primary sensory neurons responsible for proprioception as they are detecting joint position and movement, and muscle tension. Electrical activity from crustacean proprioceptors and tension receptors is recorded by basic neurophysiological instrumentation, and a transducer is used to simultaneously measure force that is generated by stimulating a motor nerve. In addition, we demonstrate how to stain the neurons for a quick assessment of their anatomical arrangement or for permanent fixation. Staining reveals anatomical organization that is representative of chordotonal organs in most crustaceans. Comparing the tension nerve responses to the proprioceptive responses is an effective teaching tool in determining how these sensory neurons are defined functionally and how the anatomy is correlated to the function. Three staining techniques are presented allowing researchers and instructors to choose a method that is ideal for their laboratory.
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