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Basatinya AM, Sajedianfard J, Nazifi S, Hosseinzadeh S. The analgesic effects of insulin and its disorders in streptozotocin-induced short-term diabetes. Physiol Rep 2024; 12:e16009. [PMID: 38639646 PMCID: PMC11027902 DOI: 10.14814/phy2.16009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/01/2024] [Accepted: 04/01/2024] [Indexed: 04/20/2024] Open
Abstract
Evidence suggests that insulin resistance plays an important role in developing diabetes complications. The association between insulin resistance and pain perception is less well understood. This study aimed to investigate the effects of peripheral insulin deficiency on pain pathways in the brain. Diabetes was induced in 60 male rats with streptozotocin (STZ). Insulin was injected into the left ventricle of the brain by intracerebroventricular (ICV) injection, then pain was induced by subcutaneous injection of 2.5% formalin. Samples were collected at 4 weeks after STZ injection. Dopamine (DA), serotonin, reactive oxygen species (ROS), and mitochondrial glutathione (mGSH) were measured by ELISA, and gene factors were assessed by RT-qPCR. In diabetic rats, the levels of DA, serotonin, and mGSH decreased in the nuclei of the thalamus, raphe magnus, and periaqueductal gray, and the levels of ROS increased. In addition, the levels of expression of the neuron-specific enolase and receptor for advanced glycation end genes increased, but the expression of glial fibrillary acidic protein expression was reduced. These results support the findings that insulin has an analgesic effect in non-diabetic rats, as demonstrated by the formalin test. ICV injection of insulin reduces pain sensation, but this was not observed in diabetic rats, which may be due to cell damage ameliorated by insulin.
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Affiliation(s)
| | - Javad Sajedianfard
- Department of Basic Sciences, School of Veterinary MedicineShiraz UniversityShirazIran
| | - Saeed Nazifi
- Department of Clinical Science, School of Veterinary MedicineShiraz UniversityShirazIran
| | - Saied Hosseinzadeh
- Department of Food Hygiene and Public Health, School of Veterinary MedicineShiraz UniversityShirazIran
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2
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DuBreuil DM, Chiang BM, Zhu K, Lai X, Flynn P, Sapir Y, Wainger BJ. A high-content platform for physiological profiling and unbiased classification of individual neurons. CELL REPORTS METHODS 2021; 1:100004. [PMID: 34318289 PMCID: PMC8312640 DOI: 10.1016/j.crmeth.2021.100004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/18/2021] [Accepted: 03/11/2021] [Indexed: 11/29/2022]
Abstract
High-throughput physiological assays lose single-cell resolution, precluding subtype-specific analyses of activation mechanism and drug effects. We demonstrate APPOINT (automated physiological phenotyping of individual neuronal types), a physiological assay platform combining calcium imaging, robotic liquid handling, and automated analysis to generate physiological activation profiles of single neurons at large scale. Using unbiased techniques, we quantify responses to sequential stimuli, enabling subgroup identification by physiology and probing of distinct mechanisms of neuronal activation within subgroups. Using APPOINT, we quantify primary sensory neuron activation by metabotropic receptor agonists and identify potential contributors to pain signaling. We expand the role of neuroimmune interactions by showing that human serum directly activates sensory neurons, elucidating a new potential pain mechanism. Finally, we apply APPOINT to develop a high-throughput, all-optical approach for quantification of activation threshold and pharmacologically validate contributions of ion channel families to optical activation.
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Affiliation(s)
- Daniel M. DuBreuil
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Brenda M. Chiang
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Kevin Zhu
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Xiaofan Lai
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Patrick Flynn
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Yechiam Sapir
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Brian J. Wainger
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Department of Anesthesiology, Critical Care, & Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
- Broad Institute of Harvard University and MIT, Cambridge, MA 02142, USA
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3
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Brouns I, Verckist L, Pintelon I, Timmermans JP, Adriaensen D. Pulmonary Sensory Receptors. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2021; 233:1-65. [PMID: 33950466 DOI: 10.1007/978-3-030-65817-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Inge Brouns
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium.
| | - Line Verckist
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Dirk Adriaensen
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
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Functional Exploration of the Pulmonary NEB ME. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2021; 233:31-67. [PMID: 33950469 DOI: 10.1007/978-3-030-65817-5_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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5
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Piezo2 Mediates Low-Threshold Mechanically Evoked Pain in the Cornea. J Neurosci 2020; 40:8976-8993. [PMID: 33055278 DOI: 10.1523/jneurosci.0247-20.2020] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 12/22/2022] Open
Abstract
Mammalian Piezo2 channels are essential for transduction of innocuous mechanical forces by proprioceptors and cutaneous touch receptors. In contrast, mechanical responses of somatosensory nociceptor neurons evoking pain, remain intact or are only partially reduced in Piezo2-deficient mice. In the eye cornea, comparatively low mechanical forces are detected by polymodal and pure mechanosensory trigeminal ganglion neurons. Their activation always evokes ocular discomfort or pain and protective reflexes, thus being a unique model to study mechanotransduction mechanisms in this particular class of nociceptive neurons. Cultured male and female mouse mechano- and polymodal nociceptor corneal neurons display rapidly, intermediately and slowly adapting mechanically activated currents. Immunostaining of the somas and peripheral axons of corneal neurons responding only to mechanical force (pure mechano-nociceptor) or also exhibiting TRPV1 (transient receptor potential cation channel subfamily V member 1) immunoreactivity (polymodal nociceptor) revealed that they express Piezo2. In sensory-specific Piezo2-deficient mice, the distribution of corneal neurons displaying the three types of mechanically evoked currents is similar to the wild type; however, the proportions of rapidly adapting neurons, and of intermediately and slowly adapting neurons were significantly reduced. Recordings of mechano- and polymodal-nociceptor nerve terminals in the corneal surface of Piezo2 conditional knock-out mice revealed a reduced number of mechano-sensitive terminals and lower frequency of nerve terminal impulse discharges under mechanical stimulation. Eye blinks evoked by von Frey filaments applied on the cornea were lower in Piezo2-deficient mice compared with wild type. Together, our results provide direct evidence that Piezo2 channels support mechanically activated currents of different kinetics in corneal trigeminal neurons and contributes to transduction of mechanical forces by corneal nociceptors.SIGNIFICANCE STATEMENT The cornea is a richly innervated and highly sensitive tissue. Low-threshold mechanical forces activate corneal receptors evoking discomfort or pain. To examine the contribution of Piezo2, a low-threshold mechanically activated channel, to acute ocular pain, we characterized the mechanosensitivity of corneal sensory neurons. By using Piezo2 conditional knock-out mice, we show that Piezo2 channels, present in the cell body and terminals of corneal neurons, are directly involved in acute corneal mechano-nociception. Inhibition of Piezo2 for systemic pain treatment is hindered because of its essential role for mechano-transduction processes in multiple body organs. Still, topical modulation of Piezo2 in the cornea may be useful to selectively relief unpleasant sensations and pain associated with mechanical irritation accompanying many ocular surface disorders.
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Roles of volume-regulatory anion channels, VSOR and Maxi-Cl, in apoptosis, cisplatin resistance, necrosis, ischemic cell death, stroke and myocardial infarction. CURRENT TOPICS IN MEMBRANES 2019; 83:205-283. [DOI: 10.1016/bs.ctm.2019.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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de la Peña E, Gomis A. Characterization of TRPC Channels in a Heterologous System Using Calcium Imaging and the Patch-Clamp Technique. Methods Mol Biol 2019; 1987:83-97. [PMID: 31028675 DOI: 10.1007/978-1-4939-9446-5_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The family of transient receptor potential (TRPs) channels contains 28 mammalian members, each a unique cellular sensor that responds to a wide variety of external and internal signals. TRP channels are expressed by most mammalian cells, where they are involved in many different physiological functions. Canonical TRP channels (TRPCs) form a family of nonselective cationic channels, although with greater selectivity for Ca2+. This family is made up of seven members (TRPC1-7), all of which contain a TRP box in the carboxyl terminal and 3-4 ankyrin repeats in the amino terminal. While these channels share some similar properties, they display diverse gating mechanisms and are involved in different signaling pathways (Gees M et al., Compr Physiol, 2012). The activation or inhibition of these channels has been studied using different approaches and techniques. Here, we characterize the activation of the TRPC5 channel expressed in a heterologous system, using calcium imaging and the patch-clamp technique in whole-cell configuration.
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Affiliation(s)
| | - Ana Gomis
- Instituto de Neurociencias, UMH-CSIC, Alicante, Spain.
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8
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Tay A, Schweizer FE, Di Carlo D. Micro- and nano-technologies to probe the mechano-biology of the brain. LAB ON A CHIP 2016; 16:1962-1977. [PMID: 27161943 DOI: 10.1039/c6lc00349d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Biomechanical forces have been demonstrated to influence a plethora of neuronal functions across scales including gene expression, mechano-sensitive ion channels, neurite outgrowth and folding of the cortices in the brain. However, the detailed roles biomechanical forces may play in brain development and disorders has seen limited study, partly due to a lack of effective methods to probe the mechano-biology of the brain. Current techniques to apply biomechanical forces on neurons often suffer from low throughput and poor spatiotemporal resolution. On the other hand, newly developed micro- and nano-technologies can overcome these aforementioned limitations and offer advantages such as lower cost and possibility of non-invasive control of neuronal circuits. This review compares the range of conventional, micro- and nano-technological techniques that have been developed and how they have been or can be used to understand the effect of biomechanical forces on neuronal development and homeostasis.
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Affiliation(s)
- Andy Tay
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA and Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore
| | - Felix E Schweizer
- Department of Neurobiology, University of California, Los Angeles, CA 90095, USA
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA and California Nanosystems Institute, University of California, Los Angeles, CA 90095, USA and Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA.
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9
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A critical role for Piezo2 channels in the mechanotransduction of mouse proprioceptive neurons. Sci Rep 2016; 6:25923. [PMID: 27184818 PMCID: PMC4869095 DOI: 10.1038/srep25923] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/25/2016] [Indexed: 01/30/2023] Open
Abstract
Proprioceptors are responsible for the conscious sensation of limb position and movement, muscle tension or force, and balance. Recent evidence suggests that Piezo2 is a low threshold mechanosensory receptor in the peripheral nervous system, acting as a transducer for touch sensation and proprioception. Thus, we characterized proprioceptive neurons in the mesencephalic trigeminal nucleus that are involved in processing proprioceptive information from the face and oral cavity. This is a specific population of neurons that produce rapidly adapting mechanically-activated currents that are fully dependent on Piezo2. As such, we analyzed the deficits in balance and coordination caused by the selective deletion of the channel in proprioceptors (conditional knockout). The data clearly shows that Piezo2 fulfills a critical role in a defined homogeneous population of proprioceptor neurons that innervate the head muscles, demonstrating that this ion channel is essential for mammalian proprioceptive mechanotransduction.
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Bernardeschi I, Greco F, Ciofani G, Marino A, Mattoli V, Mazzolai B, Beccai L. A soft, stretchable and conductive biointerface for cell mechanobiology. Biomed Microdevices 2016; 17:46. [PMID: 25797705 DOI: 10.1007/s10544-015-9950-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In mechanobiology the study of cell response to mechanical stimuli is fundamental, and the involved processes (i.e., mechanotransduction) need to be investigated by interfacing (mechanically and electrically) with the cells in dynamic and non-invasive natural-like conditions. In this work, we present a novel soft, stretchable and conductive biointerface that allows both cell mechanical stimulation and dynamic impedance recording. The biointerface stretchability and conductivity, jointly to the biocompatibility and transparency needed to perform cell culture studies, were obtained by exploiting the formation of wrinkles on the surface of a 90 nm thick conductive layer of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on a pre-stretched 130 μm thick poly(dimethylsiloxane) (PDMS) substrate. Cell adhesion and proliferation of SH-SY5Y human neuroblastoma cells were evaluated, and cell differentiation on the corrugated surface was assessed. We demonstrate how the biointerface remains conductive when applying uniaxial strain up to 10%, and when cell culturing is performed. Finally, a reduction of about 30% of the relative impedance variation signal was measured, with respect to the control, as a result of the mechanical stimulation of cells.
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Affiliation(s)
- Irene Bernardeschi
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Viale Rinaldo Piaggio 34, 56025, Pontedera, PI, Italy
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11
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Hyaluronan modulates TRPV1 channel opening, reducing peripheral nociceptor activity and pain. Nat Commun 2015; 6:8095. [PMID: 26311398 PMCID: PMC4560824 DOI: 10.1038/ncomms9095] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 07/17/2015] [Indexed: 01/31/2023] Open
Abstract
Hyaluronan (HA) is present in the extracellular matrix of all body tissues, including synovial fluid in joints, in which it behaves as a filter that buffers transmission of mechanical forces to nociceptor nerve endings thereby reducing pain. Using recombinant systems, mouse-cultured dorsal root ganglia (DRG) neurons and in vivo experiments, we found that HA also modulates polymodal transient receptor potential vanilloid subtype 1 (TRPV1) channels. HA diminishes heat, pH and capsaicin (CAP) responses, thus reducing the opening probability of the channel by stabilizing its closed state. Accordingly, in DRG neurons, HA decreases TRPV1-mediated impulse firing and channel sensitization by bradykinin. Moreover, subcutaneous HA injection in mice reduces heat and capsaicin nocifensive responses, whereas the intra-articular injection of HA in rats decreases capsaicin joint nociceptor fibres discharge. Collectively, these results indicate that extracellular HA reduces the excitability of the ubiquitous TRPV1 channel, thereby lowering impulse activity in the peripheral nociceptor endings underlying pain. Hyaluronan is a major component of the extracellular matrix, and is used to treat joint pain in osteoarthritis. In this study, Caires et al. show hyaluronan achieves its analgesic effects by targeting TRPV1 and stabilising the channel in its closed state.
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12
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Quallo T, Vastani N, Horridge E, Gentry C, Parra A, Moss S, Viana F, Belmonte C, Andersson DA, Bevan S. TRPM8 is a neuronal osmosensor that regulates eye blinking in mice. Nat Commun 2015; 6:7150. [PMID: 25998021 PMCID: PMC4455064 DOI: 10.1038/ncomms8150] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 04/13/2015] [Indexed: 01/23/2023] Open
Abstract
Specific peripheral sensory neurons respond to increases in extracellular osmolality but the mechanism responsible for excitation is unknown. Here we show that small increases in osmolality excite isolated mouse dorsal root ganglion (DRG) and trigeminal ganglion (TG) neurons expressing the cold-sensitive TRPM8 channel (transient receptor potential channel, subfamily M, member 8). Hyperosmotic responses were abolished by TRPM8 antagonists, and were absent in DRG and TG neurons isolated from Trpm8(-/-) mice. Heterologously expressed TRPM8 was activated by increased osmolality around physiological levels and inhibited by reduced osmolality. Electrophysiological studies in a mouse corneal preparation demonstrated that osmolality regulated the electrical activity of TRPM8-expressing corneal afferent neurons. Finally, the frequency of eye blinks was reduced in Trpm8(-/-) compared with wild-type mice and topical administration of a TRPM8 antagonist reduced blinking in wild-type mice. Our findings identify TRPM8 as a peripheral osmosensor responsible for the regulation of normal eye-blinking in mice.
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Affiliation(s)
- Talisia Quallo
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Nisha Vastani
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Elisabeth Horridge
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Clive Gentry
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Andres Parra
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - Sian Moss
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Felix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - David A. Andersson
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Stuart Bevan
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
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13
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Dong H, Jiang Y, Dong J, Mittal RK. Inhibitory motor neurons of the esophageal myenteric plexus are mechanosensitive. Am J Physiol Cell Physiol 2014; 308:C405-13. [PMID: 25540174 DOI: 10.1152/ajpcell.00159.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mechanosensitivity of enteric neurons has been reported in the small intestine and colon, but not in the esophagus. Our earlier in vivo studies show that mechanical stretch of the esophagus in the axial direction induces neurally mediated relaxation of the lower esophageal sphincter, possibly through mechanosensitive motor neurons. However, this novel notion that the motor neurons are mechanosensitive has not been examined in isolated esophageal myenteric motor neurons. The goal of our present study was to examine the mechanosensitivity of esophageal motor neurons in primary culture and elucidate the underlying molecular mechanisms. Immmunocytochemical analysis revealed that >95% cells were positive for the neuronal marker protein gene product 9.5 and that 66% of these cells costained with protein gene product 9.5 and neuronal nitric oxide (NO) synthase. Hypotonic solution induced an increase in the cytoplasm volume in all cells that was independent of extracellular Ca(2+). Hypotonic solution and mechanical stretch induced cytoplasmic free Ca(2+) signaling in ~65% of neurons in the presence, but not absence, of extracellular Ca(2+). Neurons grown on the elastic membrane responded to mechanical stretch by an increase in neuronal size and Ca(2+) signaling simultaneously. Hypotonic stretch-induced cytoplasmic free Ca(2+) signaling was not affected by extracellular Mg(2+), 5-nitro-2-(3-phenylpropylamino)benzoic acid, and nifedipine but was attenuated by 2-aminoethoxydiphenyl borate, Gd(3+), and Grammostola mechanotoxin 4, blockers of the stretch-activated ion channels. In ~57% of the neurons, hypotonic stretch also induced Ca(2+)-dependent cytoplasmic NO production, which was abolished by Grammostola mechanotoxin 4. These results prove that the esophageal inhibitory motor neurons possess a mechanosensitive property and also provide novel insights into the stretch-activated ion channel-Ca(2+)-NO signaling pathway in these neurons.
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Affiliation(s)
- Hui Dong
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California; and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Yanfen Jiang
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California; and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Jane Dong
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California; and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Ravinder K Mittal
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California; and Veterans Affairs San Diego Healthcare System, San Diego, California
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Lembrechts R, Brouns I, Schnorbusch K, Pintelon I, Timmermans JP, Adriaensen D. Neuroepithelial bodies as mechanotransducers in the intrapulmonary airway epithelium: involvement of TRPC5. Am J Respir Cell Mol Biol 2012; 47:315-23. [PMID: 22461428 DOI: 10.1165/rcmb.2012-0068oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In rodent lungs, a major part of the myelinated vagal airway afferents selectively contacts pulmonary neuroepithelial bodies (NEBs). Because most myelinated vagal airway afferents concern physiologically characterized mechanoreceptors, the present study aimed at unraveling the potential involvement of NEB cells in transducing mechanosensory information from the airways to the central nervous system. Physiological studies were performed using confocal Ca(2+) imaging of airway epithelium in murine lung slices. Mechanical stimulation by short-term application of a mild hypoosmotic solution (230 mosmol) resulted in a selective, fast, reversible, and reproducible Ca(2+) rise in NEB cells. Other airway epithelial cells could only be activated using more severe hypoosmotic stimuli (< 200 mosmol). NEB cells selectively expressed the Ca(2+)-permeable osmo- and mechanosensitive transient receptor potential canonical channel 5 (TRPC5) in their apical membranes, whereas immunoreactivity for TRP vanilloid-4 and TRP melastatin-3 was abundant in virtually all other airway epithelial cells. Hypoosmotic activation of NEB cells was prevented by GsMTx-4, an inhibitor of mechanosensitive ion channels, and by SKF96365, an inhibitor of TRPC channels. Short application of gadolinium, reported to activate TRPC5 channels, evoked a transient Ca(2+) rise in NEB cells. Osmomechanical activation of NEB cells gave rise to a typical delayed activation of Clara-like cells due to the release of ATP from NEB cells. Because ATP may activate the NEB-associated P2X(2/3) ATP receptor expressing myelinated vagal afferents, the current observations strongly suggest that pulmonary NEB cells are fully equipped to initiate mechanosensory signal transduction to the central nervous system via a purinergic signaling pathway.
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Affiliation(s)
- Robrecht Lembrechts
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
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15
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Bautista DM, Lumpkin EA. Perspectives on: information and coding in mammalian sensory physiology: probing mammalian touch transduction. ACTA ACUST UNITED AC 2012; 138:291-301. [PMID: 21875978 PMCID: PMC3171080 DOI: 10.1085/jgp.201110637] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Diana M Bautista
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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Boudes M, Scamps F. Calcium-activated chloride current expression in axotomized sensory neurons: what for? Front Mol Neurosci 2012; 5:35. [PMID: 22461766 PMCID: PMC3309971 DOI: 10.3389/fnmol.2012.00035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 03/02/2012] [Indexed: 11/13/2022] Open
Abstract
Calcium-activated chloride currents (CaCCs) are activated by an increase in intracellular calcium concentration. Peripheral nerve injury induces the expression of CaCCs in a subset of adult sensory neurons in primary culture including mechano- and proprioceptors, though not nociceptors. Functional screenings of potential candidate genes established that Best1 is a molecular determinant for CaCC expression among axotomized sensory neurons, while Tmem16a is acutely activated by inflammatory mediators in nociceptors. In nociceptors, such CaCCs are preferentially activated under receptor-induced calcium mobilization contributing to cell excitability and pain. In axotomized mechano- and proprioceptors, CaCC activation does not promote electrical activity and prevents firing, a finding consistent with electrical silencing for growth competence of adult sensory neurons. In favor of a role in the process of neurite growth, CaCC expression is temporally correlated to neurons displaying a regenerative mode of growth. This perspective focuses on the molecular identity and role of CaCC in axotomized sensory neurons and the future directions to decipher the cellular mechanisms regulating CaCC during neurite (re)growth.
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Affiliation(s)
- Mathieu Boudes
- INSERM U-1051, Sensory Diseases, Neuro-plasticity and Therapy, Institut des Neurosciences de Montpellier Montpellier, France
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Marshall KL, Lumpkin EA. The molecular basis of mechanosensory transduction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 739:142-55. [PMID: 22399400 PMCID: PMC4060607 DOI: 10.1007/978-1-4614-1704-0_9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Multiple senses, including hearing, touch and osmotic regulation, require the ability to convert force into an electrical signal: A process called mechanotransduction. Mechanotransduction occurs through specialized proteins that open an ion channel pore in response to a mechanical stimulus. Many of these proteins remain unidentified in vertebrates, but known mechanotransduction channels in lower organisms provide clues into their identity and mechanism. Bacteria, fruit flies and nematodes have all been used to elucidate the molecules necessary for force transduction. This chapter discusses many different mechanical senses and takes an evolutionary approach to review the proteins responsible for mechanotransduction in various biological kingdoms.
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Affiliation(s)
- Kara L. Marshall
- Integrated Graduate Program in Cellular, Molecular, Structural and Genetic Studies, Columbia University College of Physicians & Surgeons, New York, NY 10032
| | - Ellen A. Lumpkin
- Departments of Dermatology and Physiology and Cellular Biophysics, Columbia University College of Physicians & Surgeons, New York, NY 10032
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Pharmacological and functional properties of TRPM8 channels in prostate tumor cells. Pflugers Arch 2010; 461:99-114. [PMID: 21052713 DOI: 10.1007/s00424-010-0895-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 10/09/2010] [Accepted: 10/11/2010] [Indexed: 10/18/2022]
Abstract
Prostate cancer (PC) is a major health problem in adult males. TRPM8, a cationic TRP channel activated by cooling and menthol is upregulated in PC. However, the precise role of TRPM8 in PC is still unclear. Some studies hypothesized that TRPM8-mediated transmembrane Ca(2+) fluxes play a key role in cellular proliferation of PC cells. In contrast, other findings suggest that high TRPM8 levels may reduce the metastatic potential of PC cells. A detailed understanding of the response of TRPM8 channels to pharmacological modulators of their activity is relevant when considering potential therapies, targeting this ion channel to treat PC. We characterized the pharmacological and functional properties of native TRPM8 channels in four human prostate cell lines, PNT1A, LNCaP, DU145, and PC3, commonly used as experimental models of PC. PNT1A is a non-tumoral prostate cell line while the other three correspond to different stages of PC. Here, we show that cold- and agonist-evoked [Ca(2+)](i) responses in PC cells are much less sensitive to well-characterized agonists (menthol and icilin) and antagonists (BCTC, clotrimazole, and DD01050) of TRPM8 channels, compared to TRPM8 channels in other tissues, suggesting a different molecular composition and/or spatial organization. In addition, the forced overexpression of human TRPM8 facilitated the trafficking of TRPM8 channels residing in the endoplasmic reticulum to the plasma membrane, leading to a marked potentiation in the efficacy of the different blockers. These results predict that blockers of canonical TRPM8 channels may be less effective in halting proliferation of PC cells than expected.
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Harvey VL, Saul MW, Garner C, McDonald RL. A role for the volume regulated anion channel in volume regulation in the murine CNS cell line, CAD. Acta Physiol (Oxf) 2010; 198:159-68. [PMID: 19811460 DOI: 10.1111/j.1748-1716.2009.02050.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM The role of the volume regulated anion channel (VRAC) in a model CNS neuronal cell line, CAD, was investigated. METHODS Changes in cell volume following hypotonic challenges were measured using a video-imaging technique. The effect of the Cl(-) channel antagonists tamoxifen (10 microm) and 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS; 100 microm) on regulatory volume decrease (RVD) were measured. The whole-cell voltage-clamp technique was used to characterize ICl(swell), the current underlying the VRAC. RESULTS Using the video-imaging technique, CAD cells were found to swell and subsequently exhibit RVD when subjected to a sustained hypotonic challenge from 300 mOsmol kg(-1) H(2)O to 210 mOsmol kg(-1) H(2)O. In the presence of tamoxifen (10 microm) or DIDS (100 microm) RVD was abolished, suggesting a role for the VRAC. A hypotonic solution (230 mOsmol kg(-1) H(2)O) evoked ICl(swell), an outwardly rectifying current displaying time-independent activation, which reversed upon return to isotonic conditions. The reversal potential (E(rev)) for ICl(swell) was -14.7 + or - 1.4 mV, similar to the theoretical E(rev) for a selective Cl(-) conductance. ICl(swell) was inhibited in the presence of DIDS (100 microm) and tamoxifen (10 microm), the DIDS inhibition being voltage dependent. CONCLUSIONS Osmotic swelling elicits an outwardly rectifying Cl(-) conductance in CAD cells. The ICl(swell) observed in these cells is similar to that observed in other cells, and is likely to provide a pathway for the loss of Cl(-) which leads to water loss and RVD. As ischaemia, brain trauma, hypoxia and other brain pathologies can cause cell swelling, CAD cells represent a model cell line for the study of neuronal cell volume regulation.
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Affiliation(s)
- V L Harvey
- Neuroscience, Pharmacology & Physiology, University College London, Gower Street, London WC1E 6BT, UK.
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20
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Dolu N, Ozesmi C, Comu N, Süer C, Gölgeli A. EFFECT OF HYPERGLYCEMIA ON ELECTRODERMAL ACTIVITY IN DIABETIC RATS. Int J Neurosci 2009; 116:715-29. [PMID: 16753897 DOI: 10.1080/00207450600675027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study investigated the relationship between hyperglycemia and electrodermal activity (EDA) parameters in streptozotocin (STZ) induced diabetic rats. The article evaluates the course of development of neurophysiological alterations in the peripheral nervous system in diabetic rats through EDA. Rats were made diabetic using a moderate dose of STZ (DI) and high dose (DII). The placebo group (P) was injected with physiological saline. EDA was recorded 1 h before the injection (beginning, 0, day), 1st day (one day after the injection) and 10th day. Skin conductance level (SCL) was lower in DII than P on the 1st and the 10th days. The SCL and SC fluctuation rate (SCFr) of DI were significantly lower on the 10th day compared to their first record. SC response rate (SCRr) was lower on the 10th day compared to the 1st day, in the DI. In the DI, SCL, SC fluctuation rate (SCFr) and SC response rate (SCRr) were lower on the 10th day compared to the 1st day. The DII was statistically higher in electrodermal non-responsiveness compared to other groups on the 1st day. The results obtained show that hyperglycemia affects the peripheral nervous system, and EDA parameters are affected by blood glucose level. It is suggested that EDA is a simple and non-invasive electrophysiological method in early diagnosis of diabetic neuropathy.
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Affiliation(s)
- Nazan Dolu
- University of Erciyes Faculty of Medicine Department of Physiology, Kayseri, Turkey.
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21
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Variable threshold of trigeminal cold-thermosensitive neurons is determined by a balance between TRPM8 and Kv1 potassium channels. J Neurosci 2009; 29:3120-31. [PMID: 19279249 DOI: 10.1523/jneurosci.4778-08.2009] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Molecular determinants of threshold differences among cold thermoreceptors are unknown. Here we show that such differences correlate with the relative expression of I(KD), a current dependent on Shaker-like Kv1 channels that acts as an excitability brake, and I(TRPM8), a cold-activated excitatory current. Neurons responding to small temperature changes have high functional expression of TRPM8 (transient receptor potential cation channel, subfamily M, member 8) and low expression of I(KD). In contrast, neurons activated by lower temperatures have a lower expression of TRPM8 and a prominent I(KD). Otherwise, both subpopulations have nearly identical membrane and firing properties, suggesting that they belong to the same neuronal pool. Blockade of I(KD) shifts the threshold of cold-sensitive neurons to higher temperatures and augments cold-evoked nocifensive responses in mice. Similar behavioral effects of I(KD) blockade were observed in TRPA1(-/-) mice. Moreover, only a small percentage of trigeminal cold-sensitive neurons were activated by TRPA1 agonists, suggesting that TRPA1 does not play a major role in the detection of low temperatures by uninjured somatic cold-specific thermosensory neurons under physiological conditions. Collectively, these findings suggest that innocuous cooling sensations and cold discomfort are signaled by specific low- and high-threshold cold thermoreceptor neurons, differing primarily in their relative expression of two ion channels having antagonistic effects on neuronal excitability. Thus, although TRPM8 appears to function as a critical cold sensor in the majority of peripheral sensory neurons, the expression of Kv1 channels in the same terminals seem to play an important role in the peripheral gating of cold-evoked discomfort and pain.
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22
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Staaf S, Maxvall I, Lind U, Husmark J, Mattsson JP, Ernfors P, Pierrou S. Down regulation of TRPC1 by shRNA reduces mechanosensitivity in mouse dorsal root ganglion neurons in vitro. Neurosci Lett 2009; 457:3-7. [PMID: 19429150 DOI: 10.1016/j.neulet.2009.03.082] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 03/23/2009] [Accepted: 03/24/2009] [Indexed: 11/25/2022]
Abstract
Mechanosensitivity is a crucial but poorly understood property of the sensory nervous system. Transient receptor potential (TRP) channels, which have been found to be responsible for the detection of other sensory stimuli such as temperature and pungent chemicals, have been suggested to also recognize stretch or pressure to cell membranes. TRPC1 is one candidate from studies in oocytes but evidence in native sensory neurons has been lacking. Therefore, we have measured an increase in intracellular Ca(2+) levels upon mechanical activation of native mouse dorsal root ganglion (DRG) neurons in culture using hypoosmolar buffer. Our results show that down regulation of TRPC1 with short hairpin RNA results in a 65% reduction of neurons with stretch activated responses. These results implicate a direct or indirect involvement of TRPC1 in the mechanosensitivity of DRG neurons.
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Affiliation(s)
- Susanne Staaf
- Department of Bioscience, AstraZeneca R&D Mölndal, Mölndal, Sweden.
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23
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Radial stretch reveals distinct populations of mechanosensitive mammalian somatosensory neurons. Proc Natl Acad Sci U S A 2008; 105:20015-20. [PMID: 19060212 DOI: 10.1073/pnas.0810801105] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Primary afferent somatosensory neurons mediate our sense of touch in response to changes in ambient pressure. Molecules that detect and transduce thermal stimuli have been recently identified, but mechanisms underlying mechanosensation, particularly in vertebrate organisms, remain enigmatic. Traditionally, mechanically evoked responses in somatosensory neurons have been assessed one cell at a time by recording membrane currents in response to application of focal pressure, suction, or osmotic challenge. Here, we used radial stretch in combination with live-cell calcium imaging to gain a broad overview of mechanosensitive neuronal subpopulations. We found that different stretch intensities activate distinct subsets of sensory neurons as defined by size, molecular markers, or pharmacological attributes. In all subsets, stretch-evoked responses required extracellular calcium, indicating that mechanical force triggers calcium influx. This approach extends the repertoire of stimulus paradigms that can be used to examine mechanotransduction in mammalian sensory neurons, facilitating future physiological and pharmacological studies.
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24
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Viana F, Belmonte C. Potassium channels shape and brake primary sensory neurone excitability. J Physiol 2008; 586:5039-40. [PMID: 18978159 DOI: 10.1113/jphysiol.2008.163360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Felix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, 03550, Spain. @umh.es
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25
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Gomis A, Soriano S, Belmonte C, Viana F. Hypoosmotic- and pressure-induced membrane stretch activate TRPC5 channels. J Physiol 2008; 586:5633-49. [PMID: 18832422 DOI: 10.1113/jphysiol.2008.161257] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Transient receptor potential (TRP) channels mediate a wide array of sensory functions. We investigated the role of TRPC5, a poorly characterized channel widely expressed in the central and peripheral nervous system, as a potential osmosensory protein. Here we show that hypoosmotic stimulation activates TRPC5 channels resulting in a large calcium influx. The response to osmotically induced membrane stretch is blocked by GsMTx-4, an inhibitor of stretch activated ion channels. Direct hypoosmotic activation of TRPC5 is independent of phospholipase C function. However, the osmotic response is inhibited in a cell line in which PIP(2) levels are reduced by regulated overexpression of a lipid phosphatase. The response was restored by increasing intracellular PIP(2) levels through the patch pipette. The mechano-sensitivity of the channel was probed in the whole-cell configuration by application of steps of positive pressure through the patch pipette. Pressure-induced membrane stretch also activated TRPC5 channels, suggesting its role as a transducer of osmo-mechanical stimuli. We also demonstrated the expression of TRPC5 in sensory neurones which together with the osmo-mechanical characteristics of TRPC5 channels suggest its putative role in mechanosensory transduction events.
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Affiliation(s)
- Ana Gomis
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández. Av. Ramón y Cajal s/n. 03550 Sant Joan d'Alacant, Alicante, Spain.
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26
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Horváth G, Sorscher EJ. Luminal fluid tonicity regulates airway ciliary beating by altering membrane stretch and intracellular calcium. ACTA ACUST UNITED AC 2008; 65:469-75. [PMID: 18435452 DOI: 10.1002/cm.20273] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The coordinated, directional beating of airway cilia drives airway mucociliary clearance. Here we explore the hypothesis that airway surface liquid osmolarity is a key regulator of ciliary beating. Cilia in freshly isolated human and murine airways visualized with streaming video-microscopy exhibited a reciprocal dependence on a physiological range of luminal fluid osmolarities, across the entire range of ciliary activity (0-20 beats per sec). Increasing osmolarity slowed or completely abrogated, while lower osmolarity dramatically stimulated ciliary beating. In parallel, epithelial cell height and importantly, intracellular calcium levels (as judged by fluorescence imaging) also changed. Moreover, ciliary beating was stimulated by isosmotic solutions containing membrane permeant osmolytes, suggesting that cell size and membrane stretch (governed by apical fluid tonicity), rather than osmolarity itself, contribute to the activation. These findings shed light on the pathophysiology of diseases of mucociliary clearance such as cystic fibrosis and other chronic inflammatory lung diseases.
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Affiliation(s)
- György Horváth
- Department of Physiology, Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
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27
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Fisher SK, Cheema TA, Foster DJ, Heacock AM. Volume-dependent osmolyte efflux from neural tissues: regulation by G-protein-coupled receptors. J Neurochem 2008; 106:1998-2014. [PMID: 18518929 DOI: 10.1111/j.1471-4159.2008.05510.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The CNS is particularly vulnerable to reductions in plasma osmolarity, such as occur during hyponatremia, the most commonly encountered electrolyte disorder in clinical practice. In response to a lowered plasma osmolarity, neural cells initially swell but then are able to restore their original volume through the release of osmolytes, both inorganic and organic, and the exit of osmotically obligated water. Given the importance of the maintenance of cell volume within the CNS, mechanisms underlying the release of osmolytes assume major significance. In this context, we review recent evidence obtained from our laboratory and others that indicates that the activation of specific G-protein-coupled receptors can markedly enhance the volume-dependent release of osmolytes from neural cells. Of particular significance is the observation that receptor activation significantly lowers the osmotic threshold at which osmolyte release occurs, thereby facilitating the ability of the cells to respond to small, more physiologically relevant, reductions in osmolarity. The mechanisms underlying G-protein-coupled receptor-mediated osmolyte release and the possibility that this efflux can result in both physiologically beneficial and potentially harmful pathophysiological consequences are discussed.
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Affiliation(s)
- Stephen K Fisher
- Molecular and Behavioral Neuroscience Institute; and Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109-2200, USA.
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28
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Chen L, Liu C, Liu L. The modulation of voltage-gated potassium channels by anisotonicity in trigeminal ganglion neurons. Neuroscience 2008; 154:482-95. [PMID: 18456412 DOI: 10.1016/j.neuroscience.2008.03.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 03/12/2008] [Accepted: 03/19/2008] [Indexed: 12/20/2022]
Abstract
Voltage-gated potassium channels (VGPCs) play an important role in many physiological functions by controlling the electrical properties and excitability of cells. Changes in tonicity in the peripheral nervous system can activate nociceptors and produce pain. Here, using whole cell patch clamp techniques, we explore how hypo- and hypertonicity modulate VGPCs in cultured rat and mouse trigeminal ganglion (TG) neurons. We found that hypo- and hypertonicity had different effects on slow-inactivating K+ current (IK) and fast-inactivating K+ current (IA): hypotonicity increased IK but had no effect on IA while hypertonicity depressed both IK and IA. The increase of IK by hypotonicity was mimicked by transient receptor potential vanilloid 4 (TRPV4) receptor activator 4alpha-phorbol-12,13-didecanoate (4alpha-PDD) but hypotonicity did not exhibit increase in TRPV4-/- mice TG neurons, suggesting that TRPV4 receptor was involved in hypotonicity-induced response. We also found that inactivation of PKC selectively reversed the increase of IK by hypotonicity, whereas antagonism of G-protein selectively rescued the inhibitions of IK and IA by hypertonicity, indicating that different intracellular signaling pathways were required for the modulation by hypo- and hypertonicity. In summary, changes in osmolality have various effects on IK and IA and different receptors and second messenger systems are selective for the modulation of VGPCs induced by hypo- versus hypertonicity.
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Affiliation(s)
- L Chen
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, No 13, Hangkong Road, Wuhan, PR China
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29
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Haeberle H, Bryan LA, Vadakkan TJ, Dickinson ME, Lumpkin EA. Swelling-activated Ca2+ channels trigger Ca2+ signals in Merkel cells. PLoS One 2008; 3:e1750. [PMID: 18454189 PMCID: PMC2365925 DOI: 10.1371/journal.pone.0001750] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 02/08/2008] [Indexed: 01/26/2023] Open
Abstract
Merkel cell-neurite complexes are highly sensitive touch receptors comprising epidermal Merkel cells and sensory afferents. Based on morphological and molecular studies, Merkel cells are proposed to be mechanosensory cells that signal afferents via neurotransmission; however, functional studies testing this hypothesis in intact skin have produced conflicting results. To test this model in a simplified system, we asked whether purified Merkel cells are directly activated by mechanical stimulation. Cell shape was manipulated with anisotonic solution changes and responses were monitored by Ca2+ imaging with fura-2. We found that hypotonic-induced cell swelling, but not hypertonic solutions, triggered cytoplasmic Ca2+ transients. Several lines of evidence indicate that these signals arise from swelling-activated Ca2+-permeable ion channels. First, transients were reversibly abolished by chelating extracellular Ca2+, demonstrating a requirement for Ca2+ influx across the plasma membrane. Second, Ca2+ transients were initially observed near the plasma membrane in cytoplasmic processes. Third, voltage-activated Ca2+ channel (VACC) antagonists reduced transients by half, suggesting that swelling-activated channels depolarize plasma membranes to activate VACCs. Finally, emptying internal Ca2+ stores attenuated transients by 80%, suggesting Ca2+ release from stores augments swelling-activated Ca2+ signals. To identify candidate mechanotransduction channels, we used RT-PCR to amplify ion-channel transcripts whose pharmacological profiles matched those of hypotonic-evoked Ca2+ signals in Merkel cells. We found 11 amplicons, including PKD1, PKD2, and TRPC1, channels previously implicated in mechanotransduction in other cells. Collectively, these results directly demonstrate that Merkel cells are activated by hypotonic-evoked swelling, identify cellular signaling mechanisms that mediate these responses, and support the hypothesis that Merkel cells contribute to touch reception in the Merkel cell-neurite complex.
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Affiliation(s)
- Henry Haeberle
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Leigh A. Bryan
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Tegy J. Vadakkan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mary E. Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ellen A. Lumpkin
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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30
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Changes in osmolality modulate voltage-gated calcium channels in trigeminal ganglion neurons. Brain Res 2008; 1208:56-66. [PMID: 18378217 DOI: 10.1016/j.brainres.2008.02.048] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Revised: 02/09/2008] [Accepted: 02/17/2008] [Indexed: 12/27/2022]
Abstract
Voltage-gated calcium channels (VGCCs) participate in many important physiological functions. However whether VGCCs are modulated by changes of osmolarity and involved in anisotonicity-induced nociception is still unknown. For this reason by using whole-cell patch clamp techniques in rat and mouse trigeminal ganglion (TG) neurons we tested the effects of hypo- and hypertonicity on VGCCs. We found that high-voltage-gated calcium current (I(HVA)) was inhibited by both hypo- and hypertonicity. In rat TG neurons, the inhibition by hypotonicity was mimicked by Transient Receptor Potential Vanilloid 4 receptor (TRPV4) activator but hypotonicity did not exhibit inhibition in TRPV4(-/-) mice TG neurons. Concerning the downstream signaling pathways, antagonism of PKG pathway selectively reduced the hypotonicity-induced inhibition, whereas inhibition of PLC- and PI3K-mediated pathways selectively reduced the inhibition produced by hypertonicity. In summary, although the effects of hypo- and hypertonicity show similar phenotype, receptor and intracellular signaling pathways were selective for hypo- versus hypertonicity-induced inhibition of I(HVA).
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31
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Pieraut S, Laurent-Matha V, Sar C, Hubert T, Méchaly I, Hilaire C, Mersel M, Delpire E, Valmier J, Scamps F. NKCC1 phosphorylation stimulates neurite growth of injured adult sensory neurons. J Neurosci 2007; 27:6751-9. [PMID: 17581962 PMCID: PMC6672700 DOI: 10.1523/jneurosci.1337-07.2007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peripheral nerve section promotes regenerative, elongated neuritic growth of adult sensory neurons. Although the role of chloride homeostasis, through the regulation of ionotropic GABA receptors, in the growth status of immature neurons in the CNS begins to emerge, nothing is known of its role in the regenerative growth of injured adult neurons. To analyze the intracellular Cl- variation after a sciatic nerve section in vivo, gramicidin perforated-patch recordings were used to study muscimol-induced currents in mice dorsal root ganglion neurons isolated from control and axotomized neurons. We show that the reversal potential of muscimol-induced current, E(GABA-A), was shifted toward depolarized potentials in axotomized neurons. This was attributable to Cl- influx because removal of extracellular Cl- prevented this shift. Application of bumetanide, an inhibitor of NKCC1 cotransporter and E(GABA-A) recordings in sensory neurons from NKCC1-/- mice, identified NKCC1 as being responsible for the increase in intracellular Cl- in axotomized neurons. In addition, we demonstrate with a phospho-NKCC1 antibody that nerve injury induces an increase in the phosphorylated form of NKCC1 in dorsal root ganglia that could account for intracellular Cl- accumulation. Time-lapse recordings of the neuritic growth of axotomized neurons show a faster growth velocity compared with control. Bumetanide, the intrathecal injection of NKCC1 small interfering RNA, and the use of NKCC1-/- mice demonstrated that NKCC1 is involved in determining the velocity of elongated growth of axotomized neurons. Our results clearly show that NKCC1-induced increase in intracellular chloride concentration is a major event accompanying peripheral nerve regeneration.
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Affiliation(s)
- Simon Pieraut
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | - Valérie Laurent-Matha
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Ilana Méchaly
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Eric Delpire
- Vanderbilt University, Nashville, Tennessee 37235
| | - Jean Valmier
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
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32
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Caplanusi A, Kim KJ, Lariviere E, Van Driessche W, Jans D. Swelling-Activated K+ Efflux and Regulatory Volume Decrease Efficiency in Human Bronchial Epithelial Cells. J Membr Biol 2007; 214:33-41. [PMID: 17546511 DOI: 10.1007/s00232-006-0048-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 11/07/2006] [Indexed: 11/27/2022]
Abstract
This study describes the correlation between cell swelling-induced K+ efflux and volume regulation efficiency evaluated with agents known to modulate ion channel activity and/or intracellular signaling processes in a human bronchial epithelial cell line, 16HBE14o(-1). Cells on permeable filter supports, differentiated into polarized monolayers, were monitored continuously at room temperature for changes in cell height (T(c)), as an index of cell volume, whereas (86)Rb efflux was assessed for K+ channel activity. The sudden reduction in osmolality of both the apical and basolateral perfusates (from 290 to 170 mosmol/kg H(2)O) evoked a rapid increase in cell volume by 35%. Subsequently, the regulatory volume decrease (RVD) restored cell volume almost completely (to 94% of the isosmotic value). The basolateral (86)Rb efflux markedly increased during the hyposmotic shock, from 0.50 +/- 0.03 min(-1) to a peak value of 6.32 +/- 0.07 min(-1), while apical (86)Rb efflux was negligible. Channel blockers, such as GdCl(3) (0.5 mM), quinine (0.5 mM) and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB, 100 microM), abolished the RVD. The protein tyrosine kinase inhibitors tyrphostin 23 (100 microM) and genistein (150 microM) attenuated the RVD. All agents decreased variably the hyposmosis-induced elevation in (86)Rb efflux, whereas NPPB induced a complete block, suggesting a link between basolateral K(+) and Cl(-1) efflux. Forskolin-mediated activation of adenylyl cyclase stimulated the RVD with a concomitant increase in basolateral (86)Rb efflux. These data suggest that the basolateral extrusion of K+ and Cl(-1) from 16HBE14o(-1) cells in response to cell swelling determines RVD efficiency.
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Affiliation(s)
- Adrian Caplanusi
- Laboratory of Physiology, K. U. Leuven, Campus Gasthuisberg, B-3000 Leuven, Belgium
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33
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Liu L, Chen L, Liedtke W, Simon SA. Changes in osmolality sensitize the response to capsaicin in trigeminal sensory neurons. J Neurophysiol 2007; 97:2001-15. [PMID: 17353553 DOI: 10.1152/jn.00887.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in tonicity in the peripheral nervous system can activate nociceptors and produce pain. Under local inflammatory conditions the peripheral terminals of nociceptors are subject to deviations from isotonicity. Previously it was shown that several members of the TRP(V) family of ion channels are responsive to changes in tonicity. Here we explore how changes in tonicity affect TRPV1 receptor-mediated responses to capsaicin in dissociated rat trigeminal ganglion (TG) neurons. Using whole cell patch-clamp and calcium imaging, we found that mild anisotonicity (260 and 348 mOsm/kg for hypotonicity and hypertonicity, respectively) strikingly sensitized the capsaicin-evoked current, I(caps). Confocal immunolocalization studies also revealed a modest anisotonicity-mediated redistribution of TRPV1 toward the plasma membrane of TG neurons. With respect to downstream signaling pathways, tonicity-induced sensitization of I(caps) was dependent on whether hypo- or hypertonic stimuli were applied. Specifically, antagonism of PKA- and PI3K-activated pathways appreciably reduced the hypertonicity-induced sensitization of I(caps), whereas inhibition of PKC-mediated pathways selectively reduced the sensitization produced by hypotonic solutions. In summary, whereas the overall effects of hypo- and hypertonicity resulted in a similar pattern of potentiation of I(caps), intracellular signaling pathways were selective for hypo- versus hypertonicity-induced tuning of capsaicin-activated currents.
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Affiliation(s)
- Lieju Liu
- 327 Bryan Research Building, 101 Research Drive, Duke University Medical Center, Durham NC 27710, USA.
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Abstract
Light touch, a sense of muscle position, and the responses to tissue-damaging levels of pressure all involve mechanosensitive sensory neurons that originate in the dorsal root or trigeminal ganglia. A variety of mechanisms of mechanotransduction are proposed. These ranges from direct activation of mechanically activated channels at the tips of sensory neurons to indirect effects of intracellular mediators, or chemical signals released from distended tissues, or specialized mechanosensory end organs. This chapter describes the properties of mechanosensitive channels present in sensory neurons and the potential molecular candidates that may underlie. Mechanically regulated electrical activity by touch and tissue damaging levels of pressure in sensory neurons seems to involve a variety of direct and indirect mechanisms and ion channels, and the involvement of specialized end organs in mechanotransduction complicates matters even more. Imaging studies are providing useful information about the events in the central nervous system associated with touch pain and allodynia (a pathological state where touch becomes painful this type of activity).
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Affiliation(s)
- Liam J Drew
- Molecular Nociception Group, Biology Department, University College London, London WC1E 6BT, United Kingdom
| | - Francois Rugiero
- Molecular Nociception Group, Biology Department, University College London, London WC1E 6BT, United Kingdom
| | - John N Wood
- Molecular Nociception Group, Biology Department, University College London, London WC1E 6BT, United Kingdom
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Madrid R, Donovan-Rodríguez T, Meseguer V, Acosta MC, Belmonte C, Viana F. Contribution of TRPM8 channels to cold transduction in primary sensory neurons and peripheral nerve terminals. J Neurosci 2006; 26:12512-25. [PMID: 17135413 PMCID: PMC6674899 DOI: 10.1523/jneurosci.3752-06.2006] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Transient receptor potential melastatin 8 (TRPM8) is the best molecular candidate for innocuous cold detection by peripheral thermoreceptor terminals. To dissect out the contribution of this cold- and menthol-gated, nonselective cation channel to cold transduction, we identified BCTC [N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide] as a potent and full blocker of recombinant TRPM8 channels. In cold-sensitive trigeminal ganglion neurons of mice and guinea pig, responses to menthol were abolished by BCTC. In contrast, the effect of BCTC on cold-evoked responses was variable but showed a good correlation with the presence or lack of menthol sensitivity in the same neuron, suggesting a specific blocking action of BCTC on TRPM8 channels. The biophysical properties of native cold-gated currents (I(cold)), and the currents blocked by BCTC were nearly identical, consistent with a role of this channel in cold sensing at the soma. The temperature activation threshold of native TRPM8 channels was significantly warmer than those reported in previous expression studies. The effect of BCTC on native I(cold) was characterized by a dose-dependent shift in the temperature threshold of activation. The role of TRPM8 in transduction was further investigated in the guinea pig cornea, a peripheral territory densely innervated with cold thermoreceptors. All cold-sensitive terminals were activated by menthol, suggesting the functional expression of TRPM8 channels in their membrane. However, the spontaneous activity and firing pattern characteristic of cold thermoreceptors was totally immune to TRPM8 channel blockade with BCTC or SKF96365 (1-[2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl-1H-imidazole hydrochloride). Cold-evoked responses in corneal terminals were also essentially unaffected by these drugs, whereas responses to menthol were completely abolished. The minor impairment in the ability to transduce cold stimuli by peripheral corneal thermoreceptors during TRPM8 blockade unveils an overlapping functional role for various thermosensitive mechanisms in these nerve terminals.
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Affiliation(s)
- Rodolfo Madrid
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
| | - Tansy Donovan-Rodríguez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
| | - Victor Meseguer
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
| | - Mari Carmen Acosta
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
| | - Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández–Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain
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36
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McCarter GC, Levine JD. Ionic basis of a mechanotransduction current in adult rat dorsal root ganglion neurons. Mol Pain 2006; 2:28. [PMID: 16923187 PMCID: PMC1563451 DOI: 10.1186/1744-8069-2-28] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 08/21/2006] [Indexed: 01/30/2023] Open
Abstract
Sensory mechanical transduction - necessary for hearing, proprioception, and the senses of touch and pain - remains poorly understood. In somatosensation, even the basic properties of the mechanically sensitive excitatory ionic currents that are assumed to mediate mechanical transduction are largely undescribed. We have recorded, from the soma of rat dorsal root ganglion (DRG) neurons in vitro, whole-cell ionic currents induced by the impact of a piezo-electrically driven glass probe. This transient mechanically activated current was observed in virtually all DRG neurons tested. In ion substitution experiments the current could be carried nonselectively by most cations, including divalent and organic cations, but not by chloride or sulfate ions. In addition, the mechanically activated current carried by monovalent cations was consistently blocked by millimolar concentrations of external calcium or magnesium. Based on these results, the transient mechanical transduction current observed in somatosensory neurons in vitro is mediated by large-pore mechanically gated channels nonselective for cations but impermeable to anions.
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Affiliation(s)
- Gordon C McCarter
- Department of Oral and Maxillofacial Surgery, Division of Neurosciences, University of California at San Francisco, San Francisco, CA 94143-0440, USA
- College of Pharmacy, Touro University – California, 1310 Johnson Lane, Mare Island, Vallejo, CA 94592-1118, USA
| | - Jon D Levine
- Department of Oral and Maxillofacial Surgery, Division of Neurosciences, University of California at San Francisco, San Francisco, CA 94143-0440, USA
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Jacques-Fricke BT, Seow Y, Gottlieb PA, Sachs F, Gomez TM. Ca2+ influx through mechanosensitive channels inhibits neurite outgrowth in opposition to other influx pathways and release from intracellular stores. J Neurosci 2006; 26:5656-64. [PMID: 16723522 PMCID: PMC6675278 DOI: 10.1523/jneurosci.0675-06.2006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ca2+ signals are known to be important regulators of neurite outgrowth and steering. Here we show that inhibiting Ca2+ influx through stretch-activated channels using various compounds, including a highly specific peptide isolated from Grammostola spatulata spider venom (GsMTx4), strongly accelerates the rate of neurite extension on diverse substrata and within the intact spinal cord. Consistent with the presence of stretch-activated channels, we show that Ca2+ influx is triggered by hypotonic solutions, which can be partially blocked by GsMTx4. Finally, chelating local, but not global, Ca2+ signals prevents the acceleration that is normally produced by GsMTx4. Blocking Ca2+ influx through other channel types has little or opposite effects, but release from intracellular stores is required for maximal acceleration. Together, our data suggest that Ca2+ functions at distinct microdomains in growth cones, with influx through mechanosensitive channels acting to inhibit outgrowth in opposition to influx through other plasma membrane channels and release from stores.
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Simonetti M, Fabbro A, D'Arco M, Zweyer M, Nistri A, Giniatullin R, Fabbretti E. Comparison of P2X and TRPV1 receptors in ganglia or primary culture of trigeminal neurons and their modulation by NGF or serotonin. Mol Pain 2006; 2:11. [PMID: 16566843 PMCID: PMC1448213 DOI: 10.1186/1744-8069-2-11] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 03/28/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cultured sensory neurons are a common experimental model to elucidate the molecular mechanisms of pain transduction typically involving activation of ATP-sensitive P2X or capsaicin-sensitive TRPV1 receptors. This applies also to trigeminal ganglion neurons that convey pain inputs from head tissues. Little is, however, known about the plasticity of these receptors on trigeminal neurons in culture, grown without adding the neurotrophin NGF which per se is a powerful algogen. The characteristics of such receptors after short-term culture were compared with those of ganglia. Furthermore, their modulation by chronically-applied serotonin or NGF was investigated. RESULTS Rat or mouse neurons in culture mainly belonged to small and medium diameter neurons as observed in sections of trigeminal ganglia. Real time RT-PCR, Western blot analysis and immunocytochemistry showed upregulation of P2X(3) and TRPV1 receptors after 1-4 days in culture (together with their more frequent co-localization), while P2X(2) ones were unchanged. TRPV1 immunoreactivity was, however, lower in mouse ganglia and cultures. Intracellular Ca(2+) imaging and whole-cell patch clamping showed functional P2X and TRPV1 receptors. Neurons exhibited a range of responses to the P2X agonist alpha, beta-methylene-adenosine-5'-triphosphate indicating the presence of homomeric P2X(3) receptors (selectively antagonized by A-317491) and heteromeric P2X(2/3) receptors. The latter were observed in 16 % mouse neurons only. Despite upregulation of receptors in culture, neurons retained the potential for further enhancement of P2X(3) receptors by 24 h NGF treatment. At this time point TRPV1 receptors had lost the facilitation observed after acute NGF application. Conversely, chronically-applied serotonin selectively upregulated TRPV1 receptors rather than P2X(3) receptors. CONCLUSION Comparing ganglia and cultures offered the advantage of understanding early adaptive changes of nociception-transducing receptors of trigeminal neurons. Culturing did not prevent differential receptor upregulation by algogenic substances like NGF or serotonin, indicating that chronic application led to distinct plastic changes in the molecular mechanisms mediating pain on trigeminal nociceptors.
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Affiliation(s)
- Manuela Simonetti
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Alessandra Fabbro
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Marianna D'Arco
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Marina Zweyer
- Department of Normal Human Morphology, University of Trieste, Via Manzoni 16, 34138 Trieste, Italy
| | - Andrea Nistri
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Rashid Giniatullin
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
| | - Elsa Fabbretti
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 4, 34014 Trieste, Italy
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39
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Chapter 13 Finding Sensory Neuron Mechanotransduction Components. CURRENT TOPICS IN MEMBRANES 2006. [DOI: 10.1016/s1063-5823(06)57012-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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40
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Inoue H, Mori SI, Morishima S, Okada Y. Volume-sensitive chloride channels in mouse cortical neurons: characterization and role in volume regulation. Eur J Neurosci 2005; 21:1648-58. [PMID: 15845092 DOI: 10.1111/j.1460-9568.2005.04006.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because persistent swelling causes cell damage and often results in cell death, volume regulation is an important physiological function in both neuronal and non-neuronal cells. Brain cell swelling has been observed not only in various pathological conditions but also during physiological synaptic transmissions. Volume-sensitive anion channels have been reported to play an important role in the regulatory volume decrease occurring after osmotic swelling in many cell types. In this study, using a two-photon laser scanning microscope and patch-clamp techniques, we found that mouse cortical neurons in primary culture exhibit regulatory volume decrease after transient swelling and activation of Cl- currents during exposure to a hypotonic solution. The regulatory volume decrease was inhibited by Cl- channel blockers or K+ channel blockers. Swelling-activated Cl- currents exhibited outward rectification, time-dependent inactivation at large positive potentials, a low-field anion permeability sequence, an intermediate unitary conductance and sensitivity to known blockers of volume-sensitive Cl- channels. Thus, it is concluded that the activity of the volume-sensitive outwardly rectifying Cl- channel plays a role in the control of cell volume in cortical neurons.
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Affiliation(s)
- Hana Inoue
- Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
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41
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de la Peña E, Mälkiä A, Cabedo H, Belmonte C, Viana F. The contribution of TRPM8 channels to cold sensing in mammalian neurones. J Physiol 2005; 567:415-26. [PMID: 15961432 PMCID: PMC1474199 DOI: 10.1113/jphysiol.2005.086546] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Different classes of ion channels have been implicated in sensing cold temperatures at mammalian thermoreceptor nerve endings. A major candidate is TRPM8, a non-selective cation channel of the transient receptor potential family, activated by menthol and low temperatures. We investigated the role of TRPM8 in cold sensing during transient expression in mouse cultured hippocampal neurones, a tissue that lacks endogenous expression of thermosensitive TRPs. In the absence of synaptic input, control hippocampal neurones were not excited by cooling. In contrast, all TRPM8-transfected hippocampal neurones were excited by cooling and menthol. However, in comparison to cold-sensitive trigeminal sensory neurones, hippocampal neurones exhibited much lower threshold temperatures, requiring temperatures below 27 degrees C to fire action potentials. These results directly demonstrate that expression of TRPM8 in mammalian neurones induces cold sensing, albeit at lower temperatures than native TRPM8-expressing neurones, suggesting the presence of additional modulatory mechanisms in the cold response of sensory neurones.
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Affiliation(s)
- Elvira de la Peña
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Apartado 18, San Juan de Alicante, 03550 Spain.
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42
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Hjerling-Leffler J, Marmigère F, Heglind M, Cederberg A, Koltzenburg M, Enerbäck S, Ernfors P. The boundary cap: a source of neural crest stem cells that generate multiple sensory neuron subtypes. Development 2005; 132:2623-32. [PMID: 15872002 DOI: 10.1242/dev.01852] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The boundary cap (BC) is a transient neural crest-derived group of cells located at the dorsal root entry zone (DREZ) that have been shown to differentiate into sensory neurons and glia in vivo. We find that when placed in culture, BC cells self-renew, show multipotency in clonal cultures and express neural crest stem cell (NCSCs) markers. Unlike sciatic nerve NCSCs, the BC-NCSC (bNCSCs) generates sensory neurons upon differentiation. The bNCSCs constitute a common source of cells for functionally diverse types of neurons, as a single bNCSC can give rise to several types of nociceptive and thermoreceptive sensory neurons. Our data suggests that BC cells comprise a source of multipotent sensory specified stem cells that persist throughout embryogenesis.
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Affiliation(s)
- Jens Hjerling-Leffler
- Unit of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
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43
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Peng SQ, Hajela RK, Atchison WD. Fluid flow-induced increase in inward Ba2+ current expressed in HEK293 cells transiently transfected with human neuronal L-type Ca2+ channels. Brain Res 2005; 1045:116-23. [PMID: 15910769 DOI: 10.1016/j.brainres.2005.03.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 03/11/2005] [Accepted: 03/15/2005] [Indexed: 11/17/2022]
Abstract
Mechanical forces can alter the gating of several kinds of ion channels in many types of cells, but the mechanisms underlying the mechanosensitivity are not clearly understood. To date, there are very few reports on mechanosensitivity of Ca2+ channels, particularly neuronal Ca2+ channels. We examined the mechanical sensitivity of human recombinant L-type Ca2+ channels in response to fluid flow. Neuronal L-type Ca2+ channels (Ca(v) 1.2) were expressed transiently in HEK293 cells using expression cDNA clones of human alpha1C, alpha2delta, and beta subunits along with green fluorescent protein (GFP) as a reporter protein. Current (I(Ba)) through these heterologously-expressed channels was measured using whole cell recording technique with 20 mM Ba2+ as charge carrier. Transfected cells were exposed to a constant, increased fluid flow from a separate pipette during current recording. The L-type I(Ba) was found to be very sensitive to the flow-induced shear forces. Peak current amplitude increased by as much as approximately 50% during fluid flow as compared to that in the absence of fluid pressure. However, no change was observed in the amplitude of the average current during the final 5 ms of the 150-ms voltage step. Current amplitude promptly returned to normal control levels upon stopping fluid flow. The current-voltage relationship was not altered by fluid flow. The flow-induced increase in current amplitude exhibited an apparent shift in steady-state inactivation toward more negative potentials; inactivation was faster but was not voltage dependent. Activation was slightly faster under flow. Thus, increased mechanical tension associated with fluid flow can alter the fundamental properties of voltage-gated Ca2+ channels, even for channels which might not normally be exposed to fluid flow shear forces in their native environment.
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Affiliation(s)
- Shuang-Qing Peng
- Department of Pharmacology and Toxicology and Neuroscience Program, Michigan State University, B-331 Life Sciences Building, East Lansing, MI 48824-1317, USA
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44
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Waseem TV, Rakovich AA, Lavrukevich TV, Konev SV, Fedorovich SV. Calcium regulates the mode of exocytosis induced by hypotonic shock in isolated neuronal presynaptic endings. Neurochem Int 2005; 46:235-42. [PMID: 15670640 DOI: 10.1016/j.neuint.2004.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 09/20/2004] [Indexed: 11/19/2022]
Abstract
A decrease in the osmolarity of incubation medium is accompanied by calcium influx in neuronal presynaptic endings. We studied the influence of Ca2+ on exocytosis induced by hypotonic shock using the hydrophilic fluorescent dye acridine orange and the hydrophobic fluorescent dye FM2-10. It was shown using acridine orange that lowering of osmolarity to 230 mOsm/l induces exocytosis both in calcium-containing and calcium-free medium. By contrast, we were able to demonstrate calcium-dependence of exocytosis using styryl dye FM2-10. Lowering of osmolarity leads to increase of [3H]D-aspartate and [3H]GABA release in calcium-free medium. Addition of calcium inhibits hypotonic-induced neurotransmitter release. Decreasing of NaCl concentration to 92 mM in isotonic medium is able to induce d-aspartate and GABA release. Thus, our data suggest that hypotonic swelling induces calcium-independent exocytosis possibly by a "kiss and run" mechanism. Calcium influx mediated by stretch channels is able to provoke full fusion between plasma membrane and synaptic vesicles. [3H]D-aspartate and [3H]GABA released by hypotonic shock is determined by sodium lowering rather than by osmolarity decreasing itself.
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Affiliation(s)
- Tatyana V Waseem
- Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus
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45
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Chavas J, Forero ME, Collin T, Llano I, Marty A. Osmotic Tension as a Possible Link between GABAA Receptor Activation and Intracellular Calcium Elevation. Neuron 2004; 44:701-13. [PMID: 15541317 DOI: 10.1016/j.neuron.2004.11.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 08/20/2004] [Accepted: 10/28/2004] [Indexed: 11/30/2022]
Abstract
Intracellular calcium concentration rises have been reported following activation of GABA(A) receptors in neonatal preparations and attributed to activation of voltage-dependent Ca(2+) channels. However, we show that, in cerebellar interneurons, GABA(A) agonists induce a somatodendritic Ca(2+) rise that persists at least until postnatal day 20 and is not mediated by depolarization-induced Ca(2+) entry. A local Ca(2+) elevation can likewise be elicited by repetitive stimulation of presynaptic GABAergic afferent fibers. We find that, following GABA(A) receptor activation, bicarbonate-induced Cl(-) entry leads to cell depolarization, Cl(-) accumulation, and osmotic tension. We propose that this tension induces the intracellular Ca(2+) rise as part of a regulatory volume decrease reaction. This mechanism introduces an unexpected link between activation of GABA(A) receptors and intracellular Ca(2+) elevation, which could contribute to activity-driven synaptic plasticity.
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Affiliation(s)
- Joël Chavas
- Laboratoire de Physiologie Cérébrale, CNRS UMR 8118, Université Paris 5, 45 rue des Saints Pères, 75006 Paris, France
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46
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Spehr J, Spehr M, Hatt H, Wetzel CH. Subunit-specific P2X-receptor expression defines chemosensory properties of trigeminal neurons. Eur J Neurosci 2004; 19:2497-510. [PMID: 15128403 DOI: 10.1111/j.0953-816x.2004.03329.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The facial innervation pattern of trigeminal nerve fibres comprises the innervation of the nasal epithelium, where free trigeminal nerve endings contribute to detection and discrimination of chemical stimuli including odourants. The signal transduction mechanisms in sensory nerve endings underlying perception of chemical stimuli remain widely uncovered. Here, we characterized trigeminal ATP-activated P2X receptors in cultured rat trigeminal neurons and investigated their role in chemoperception. We identified a new subpopulation of neurons lacking typical nociceptive characteristics and expressing homomeric P2X(2) receptors. Using a certain group of chemicals known as trigeminal stimuli we found no direct activation of trigeminal neurons, but a modulation of P2X(2) receptor mediated currents. In contrast, P2X(3) receptor mediated currents of nociceptive trigeminal neurons remained unaffected by the tested chemicals. Therefore, we assume a functional role for the newly identified subpopulation in chemodetection of certain trigeminal stimuli.
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MESH Headings
- Adenosine Triphosphate/analogs & derivatives
- Adenosine Triphosphate/pharmacology
- Animals
- Animals, Newborn
- Benzaldehydes/pharmacology
- Calcium/metabolism
- Cells, Cultured
- Colforsin/pharmacology
- DNA, Complementary/chemistry
- Diagnostic Imaging/methods
- Dinucleoside Phosphates/pharmacology
- Dose-Response Relationship, Drug
- Drug Interactions
- Embryo, Mammalian
- Enzyme Inhibitors/pharmacology
- Green Fluorescent Proteins
- Humans
- Immunohistochemistry/methods
- Kidney
- Luminescent Proteins/metabolism
- Membrane Potentials/drug effects
- Neurites/drug effects
- Neurons/classification
- Neurons/metabolism
- Olfactory Receptor Neurons/physiology
- Organic Chemicals/pharmacology
- Patch-Clamp Techniques/methods
- Potassium/pharmacology
- Protein Subunits/metabolism
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X2
- Receptors, Purinergic P2X3
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Stimulation, Chemical
- Transfection/methods
- Triazines/pharmacology
- Trigeminal Ganglion/cytology
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Affiliation(s)
- Jennifer Spehr
- Lehrstuhl fuer Zellphysiologie, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
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47
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Wehner F, Olsen H, Tinel H, Kinne-Saffran E, Kinne RKH. Cell volume regulation: osmolytes, osmolyte transport, and signal transduction. Rev Physiol Biochem Pharmacol 2004; 148:1-80. [PMID: 12687402 DOI: 10.1007/s10254-003-0009-x] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In recent years, it has become evident that the volume of a given cell is an important factor not only in defining its intracellular osmolality and its shape, but also in defining other cellular functions, such as transepithelial transport, cell migration, cell growth, cell death, and the regulation of intracellular metabolism. In addition, besides inorganic osmolytes, the existence of organic osmolytes in cells has been discovered. Osmolyte transport systems-channels and carriers alike-have been identified and characterized at a molecular level and also, to a certain extent, the intracellular signals regulating osmolyte movements across the plasma membrane. The current review reflects these developments and focuses on the contributions of inorganic and organic osmolytes and their transport systems in regulatory volume increase (RVI) and regulatory volume decrease (RVD) in a variety of cells. Furthermore, the current knowledge on signal transduction in volume regulation is compiled, revealing an astonishing diversity in transport systems, as well as of regulatory signals. The information available indicates the existence of intricate spatial and temporal networks that control cell volume and that we are just beginning to be able to investigate and to understand.
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Affiliation(s)
- F Wehner
- Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.
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48
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Cabanes C, Viana F, Belmonte C. Differential Thermosensitivity of Sensory Neurons in the Guinea Pig Trigeminal Ganglion. J Neurophysiol 2003; 90:2219-31. [PMID: 14534264 DOI: 10.1152/jn.00299.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intracellular recordings were employed to study the effects of temperature on membrane properties and excitability in sensory neurons of the intact guinea pig trigeminal ganglion (TG) maintained in vitro. Neurons were classified according to the shape and duration of the action potential into F (short-duration, fast spike) and S (long duration, slow spike with a “hump”) types. Most type F (33/34) neurons had axons with conduction velocities >1.5 m/s, while only 30% (6/23) of type S neurons reached these conduction speeds suggesting differences in myelination. Cooling reduced axonal conduction velocity and prolonged spike duration in both neuronal types. In F-type neurons with strong inward rectification. cooling also increased the excitability, augmenting the input resistance and reducing the current firing threshold. These effects were not observed in S-type neurons lacking inward rectification. In striking contrast to results obtained in cultured TG neurons, cooling or menthol did not induce firing in recordings from the acutely isolated ganglion. However, after application of submillimolar concentrations (100 μM) of the potassium channel blocker 4-aminopyridine (4-AP), 29% previously unresponsive neurons developed cold sensitivity. An additional 31% developed ongoing activity that was sensitive to temperature. Only neurons with strong inward rectification (mostly F-type) became thermosensitive. Cooling- and 4-AP–evoked firing were insensitive to intracellular application of 4-AP or somatic membrane hyperpolarization, suggesting that their action was most prominent at the level of the axon. The lack of excitatory actions of low temperature in the excised intact ganglion contrasts with the impulse discharges induced by cooling in trigeminal nerve terminals of the same species, suggesting a critical difference between cold-transduction mechanisms at the level of the nerve terminals and the soma.
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Affiliation(s)
- C Cabanes
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones, 03550, San Juan Alicante, Spain.
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Xu F, Satoh E, Iijima T. Protein kinase C-mediated Ca2+ entry in HEK 293 cells transiently expressing human TRPV4. Br J Pharmacol 2003; 140:413-21. [PMID: 12970074 PMCID: PMC1574039 DOI: 10.1038/sj.bjp.0705443] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
1. We investigated whether protein kinase C (PKC) activation stimulates Ca2+ entry in HEK 293 cells transfected with human TRPV4 cDNA and loaded with fura-2. 2. Phorbol 12-myristate 13-acetate (PMA), a PKC-activating phorbol ester, increased the intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner, with an EC50 value of 11.7 nm. Exposure to a hypotonic solution (HTS) after PMA further increased [Ca2+]i. Two other PKC-activating phorbol esters, phorbol 12,13-didecanoate (PDD) and phorbol 12,13-dibutyrate, also caused [Ca2+]i to increase. 3. The inactive isomer 4alpha-PMA was less effective and the peak [Ca2+]i increase was significantly smaller than that induced by PMA. In contrast, 4alpha-PDD produced a monophasic or biphasic [Ca2+]i increase with a different latency, while 4alpha-phorbol had no effect. 4. The PMA-induced [Ca2+]i increase was abolished by prior exposure to bisindolylmaleimide (BIM), a PKC-specific inhibitor, and suppressed by the nonspecific PKC inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine. The [Ca2+]i increase induced by 4alpha-PMA, 4alpha-PDD or HTS was not significantly affected by BIM. 5. These results suggest that both PKC-dependent and -independent mechanisms are involved in the phorbol ester-induced activation of TRPV4, and the PKC-independent pathway is predominant in HTS-induced Ca2+ entry.
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Affiliation(s)
- Feng Xu
- Department of Pharmacology, Akita University School of Medicine, 1-1-1 Hondoh, Akita 010-8543, Japan
| | - Eisaku Satoh
- Department of Pharmacology, Akita University School of Medicine, 1-1-1 Hondoh, Akita 010-8543, Japan
| | - Toshihiko Iijima
- Department of Pharmacology, Akita University School of Medicine, 1-1-1 Hondoh, Akita 010-8543, Japan
- Author for correspondence:
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Alessandri-Haber N, Yeh JJ, Boyd AE, Parada CA, Chen X, Reichling DB, Levine JD. Hypotonicity induces TRPV4-mediated nociception in rat. Neuron 2003; 39:497-511. [PMID: 12895423 DOI: 10.1016/s0896-6273(03)00462-8] [Citation(s) in RCA: 332] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We hypothesized that TRPV4, a member of the transient receptor family of ion channels, functions as a sensory transducer for osmotic stimulus-induced nociception. We found that, as expected for a transducer molecule, TRPV4 protein is transported in sensory nerve distally toward the peripheral nerve endings. In vivo single-fiber recordings in rat showed that hypotonic solution activated 54% of C-fibers, an effect enhanced by the hyperalgesic inflammatory mediator prostaglandin E2. This osmotransduction causes nociception, since administration of a small osmotic stimulus into skin sensitized by PGE2 produced pain-related behavior. Antisense-induced decrease in expression of TRPV4 confirmed that the channel is required for hypotonic stimulus-induced nociception. Thus, we conclude that TRPV4 can function as an osmo-transducer in primary afferent nociceptive nerve fibers. Because this action is enhanced by an inflammatory mediator, TRPV4 may be important in pathological states and may be an attractive pharmacological target for the development of novel analgesics.
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Affiliation(s)
- Nicole Alessandri-Haber
- Division of Neuroscience, University of California, San Francisco, San Francisco, California 94143, USA
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