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Leite K, Garg P, Spitzner FP, Guerin Darvas S, Bähr M, Priesemann V, Kügler S. α-Synuclein Impacts on Intrinsic Neuronal Network Activity Through Reduced Levels of Cyclic AMP and Diminished Numbers of Active Presynaptic Terminals. Front Mol Neurosci 2022; 15:868790. [PMID: 35721317 PMCID: PMC9199018 DOI: 10.3389/fnmol.2022.868790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/08/2022] [Indexed: 11/23/2022] Open
Abstract
α-synuclein (α-Syn) is intimately linked to synucleinopathies like Parkinson’s disease and dementia with Lewy bodies. However, the pathophysiological mechanisms that are triggered by this protein are still largely enigmatic. α-Syn overabundance may cause neurodegeneration through protein accumulation and mitochondrial deterioration but may also result in pathomechanisms independent from neuronal cell death. One such proposed pathological mechanism is the influence of α-Syn on non-stimulated, intrinsic brain activity. This activity is responsible for more than 90% of the brain’s energyconsumption, and is thus thought to play an eminent role in basic brain functionality. Here we report that α-Syn substantially disrupts intrinsic neuronal network burst activity in a long-term neuronal cell culture model. Mechanistically, the impairment of network activity originates from reduced levels of cyclic AMP and cyclic AMP-mediated signaling as well as from diminished numbers of active presynaptic terminals. The profound reduction of network activity due to α-Syn was mediated only by intracellularly expressed α-Syn, but not by α-Syn that is naturally released by neurons. Conversely, extracellular pre-formed fibrils of α-Syn mimicked the effect of intracellular α-Syn, suggesting that they trigger an off-target mechanism that is not activated by naturally released α-Syn. A simulation-based model of the network activity in our cultures demonstrated that even subtle effect sizes in reducing outbound connectivity, i.e., loss of active synapses, can cause substantial global reductions in non-stimulated network activity. These results suggest that even low-level loss of synaptic output capabilities caused by α-Syn may result in significant functional impairments in terms of intrinsic neuronal network activity. Provided that our model holds true for the human brain, then α-Syn may cause significant functional lesions independent from neurodegeneration.
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Affiliation(s)
- Kristian Leite
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Pretty Garg
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - F. Paul Spitzner
- Neural Systems Theory group, Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Sofia Guerin Darvas
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Viola Priesemann
- Neural Systems Theory group, Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
- Institute for the Dynamics of Complex Systems, University of Göttingen, Göttingen, Germany
| | - Sebastian Kügler
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
- *Correspondence: Sebastian Kügler
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2
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Green DJ, Huang RC, Sudlow L, Hatcher N, Potgieter K, McCrohan C, Lee C, Romanova EV, Sweedler JV, Gillette MLU, Gillette R. cAMP, Ca 2+, pH i, and NO Regulate H-like Cation Channels That Underlie Feeding and Locomotion in the Predatory Sea Slug Pleurobranchaea californica. ACS Chem Neurosci 2018; 9:1986-1993. [PMID: 30067017 PMCID: PMC6128535 DOI: 10.1021/acschemneuro.8b00187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A systems approach to regulation of neuronal excitation in the mollusc Pleurobranchaea has described novel interactions of cyclic AMP-gated cation current (INa,cAMP), Ca2+, pHi, and NO. INa,cAMP appears in many neurons of feeding and locomotor neuronal networks. It is likely one of the family of hyperpolarization-activated, cyclic-nucleotide-gated currents (h-current) of vertebrate and invertebrate pacemaker networks. There are two isoforms. Ca2+ regulates both voltage dependence and depolarization-sensitive inactivation in both isoforms. The Type 1 INa,cAMP of the feeding network is enhanced by intracellular acidification. A direct dependence of INa,cAMP on cAMP allows the current to be used as a reporter on cAMP concentrations in the cell, and from there to the intrinsic activities of the synthetic adenyl cyclase and the degradative phosphodiesterase. Type 2 INa,cAMP of the locomotor system is activated by serotonergic inputs, while Type 1 of the feeding network is thought to be regulated peptidergically. NO synthase activity is high in the CNS, where it differs from standard neuronal NO synthase in not being Ca2+ sensitive. NO acidifies pHi, potentiating Type 1, and may act to open proton channels. A cGMP pathway does not mediate NO effects as in other systems. Rather, nitrosylation likely mediates its actions. An integrated model of the action of cAMP, Ca2+, pHi, and NO in the feeding network postulates that NO regulates proton conductance to cause neuronal excitation in the cell body on the one hand, and relief of activity-induced hyperacidification in fine dendritic processes on the other.
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Affiliation(s)
- Daniel J Green
- Neuroscience Program , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Rong-Chi Huang
- Department of Molecular & Integrative Physiology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Leland Sudlow
- Department of Molecular & Integrative Physiology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Nathan Hatcher
- Department of Molecular & Integrative Physiology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Kurt Potgieter
- Department of Molecular & Integrative Physiology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Catherine McCrohan
- School of Biological Sciences , University of Manchester , Manchester M13 9PT , United Kingdom
| | - Colin Lee
- Neuroscience Program , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Elena V Romanova
- Beckman Institute for Advanced Science and Technology and Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jonathan V Sweedler
- Beckman Institute for Advanced Science and Technology and Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Martha L U Gillette
- Department of Cell & Developmental Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Rhanor Gillette
- Department of Molecular & Integrative Physiology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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3
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Hackley CR, Mazzoni EO, Blau J. cAMPr: A single-wavelength fluorescent sensor for cyclic AMP. Sci Signal 2018; 11:11/520/eaah3738. [PMID: 29511120 DOI: 10.1126/scisignal.aah3738] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Genetically encoded fluorescent sensors enable cell-specific measurements of ions and small molecules in real time. Cyclic adenosine monophosphate (cAMP) is one of the most important signaling molecules in virtually all cell types and organisms. We describe cAMPr, a new single-wavelength cAMP sensor. We developed cAMPr in bacteria and embryonic stem cells and validated the sensor in mammalian neurons in vitro and in Drosophila circadian pacemaker neurons in intact brains. Comparison with other single-wavelength cAMP sensors showed that cAMPr improved the quantitative detection of cAMP abundance. In addition, cAMPr is compatible with both single-photon and two-photon imaging. This enabled us to use cAMPr together with the red fluorescent Ca2+ sensor RCaMP1h to simultaneously monitor Ca2+ and cAMP in Drosophila brains. Thus, cAMPr is a new and versatile genetically encoded cAMP sensor.
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Affiliation(s)
- Christopher R Hackley
- Department of Biology, New York University (NYU), 100 Washington Square East, New York, NY 10003, USA
| | - Esteban O Mazzoni
- Department of Biology, New York University (NYU), 100 Washington Square East, New York, NY 10003, USA.,NYU Neuroscience Institute, NYU Langone Medical Center, New York, NY 10016, USA
| | - Justin Blau
- Department of Biology, New York University (NYU), 100 Washington Square East, New York, NY 10003, USA. .,NYU Neuroscience Institute, NYU Langone Medical Center, New York, NY 10016, USA.,Center for Genomics and Systems Biology, NYU Abu Dhabi Institute, Abu Dhabi, United Arab Emirates
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4
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Potgieter K, Hatcher NG, Gillette R, McCrohan CR. Nitric oxide potentiates cAMP-gated cation current by intracellular acidification in feeding neurons of pleurobranchaea. J Neurophysiol 2010; 104:742-5. [PMID: 20484526 DOI: 10.1152/jn.00021.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A pH-sensitive cAMP-gated cation current (I(Na,cAMP)) is widely distributed in neurons of the feeding motor networks of gastropods. In the sea slug Pleurobranchaea this current is potentiated by nitric oxide (NO), which itself is produced by many feeding neurons. The action of NO is not dependent on either cGMP or cAMP signaling pathways. However, we found that NO potentiation of I(Na,cAMP) in the serotonergic metacerebral cells could be blocked by intracellular injection of MOPS buffer (pH 7.2). In neurons injected with the pH indicator BCECF, NO induced rapid intracellular acidification to several tenths of a pH unit. Intracellular pH has not previously been identified as a specific target of NO, but in this system NO modulation of I(Na,cAMP) via pH(i) may be an important regulator of the excitability of the feeding motor network.
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Affiliation(s)
- Kurt Potgieter
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA
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5
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Clemens S, Calin-Jageman R, Sakurai A, Katz PS. Altering cAMP levels within a central pattern generator modifies or disrupts rhythmic motor output. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2007; 193:1265-71. [PMID: 17972082 DOI: 10.1007/s00359-007-0280-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 11/28/2022]
Abstract
Cyclic AMP is a second messenger that has been implicated in the neuromodulation of rhythmically active motor patterns. Here, we tested whether manipulating cAMP affects swim motor pattern generation in the mollusc, Tritonia diomedea. Inhibiting adenylyl cyclase (AC) with 9-cyclopentyladenine (9-CPA) slowed or stopped the swim motor pattern. Inhibiting phosphodiesterase with 3-isobutyl-1-methylxanthine (IBMX) or applying dibutyryl-cAMP (dB-cAMP) disrupted the swim motor pattern, as did iontophoresing cAMP into the central pattern generator neuron C2. Additionally, during wash-in, IBMX sometimes temporarily produced extended or spontaneous swim motor patterns. Photolysis of caged cAMP in C2 after initiation of the swim motor pattern inhibited subsequent bursting. These results suggest that cAMP levels can dynamically modulate swim motor pattern generation, possibly shaping the output of the central pattern generator on a cycle-by-cycle basis.
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Affiliation(s)
- Stefan Clemens
- Department of Biomedical Engineering, Emory University School of Medicine/Georgia Institute of Technology, 313 Ferst Street, Atlanta, GA 30332, USA.
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6
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Straub VA, Grant J, O'Shea M, Benjamin PR. Modulation of serotonergic neurotransmission by nitric oxide. J Neurophysiol 2006; 97:1088-99. [PMID: 17135468 DOI: 10.1152/jn.01048.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) and serotonin (5-HT) are two neurotransmitters with important roles in neuromodulation and synaptic plasticity. There is substantial evidence for a morphological and functional overlap between these two neurotransmitter systems, in particular the modulation of 5-HT function by NO. Here we demonstrate for the first time the modulation of an identified serotonergic synapse by NO using the synapse between the cerebral giant cell (CGC) and the B4 neuron within the feeding network of the pond snail Lymnaea stagnalis as a model system. Simultaneous electrophysiological recordings from the pre- and postsynaptic neurons show that blocking endogenous NO production in the intact nervous system significantly reduces the B4 response to CGC activity. The blocking effect is frequency dependent and is strongest at low CGC frequencies. Conversely, bath application of the NO donor DEA/NONOate significantly enhances the CGC-B4 synapse. The modulation of the CGC-B4 synapse is mediated by the soluble guanylate cyclase (sGC)/cGMP pathway as demonstrated by the effects of the sGC antagonist 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). NO modulation of the CGC-B4 synapse can be mimicked in cell culture, where application of 5-HT puffs to isolated B4 neurons simulates synaptic 5-HT release. Bath application of diethylamine NONOate (DEA/NONOate) enhances the 5-HT induced response in the isolated B4 neuron. However, the cell culture experiment provided no evidence for endogenous NO production in either the CGC or B4 neuron suggesting that NO is produced by an alternative source. Thus we conclude that NO modulates the serotonergic CGC-B4 synapse by enhancing the postsynaptic 5-HT response.
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Affiliation(s)
- Volko A Straub
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester LE1 9HN, UK.
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7
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Hatcher NG, Sudlow LC, Moroz LL, Gillette R. Nitric oxide potentiates cAMP-gated cation current in feeding neurons of Pleurobranchaea californica independent of cAMP and cGMP signaling pathways. J Neurophysiol 2006; 95:3219-27. [PMID: 16617178 DOI: 10.1152/jn.00815.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Critical roles for nitric oxide (NO) in regulating cell and tissue physiology are broadly appreciated, but aspects remain to be explored. In the mollusk Pleurobranchaea, NO synthase activity is high in CNS ganglia containing motor networks for feeding and locomotion, where a cAMP-gated cation current (I(Na,cAMP)) is also prominent in many neurons. We examined effects of NO on I(Na,cAMP) using voltage-clamp methods developed to analyze cAMP signaling in the live neuron, focusing on the identified metacerebral giant neuron of the feeding network. NO donors enhanced the I(Na,cAMP) response to injected cAMP by an averaged 85%. In dose-response measures, NO increased the current stimulated by cAMP injection without altering either apparent cAMP binding affinity or cooperativity of current activation. NO did not detectably alter levels of native cAMP or synthesis or degradation rates as observable in both current saturation and decay rate of I(Na,cAMP) responses to cAMP injection. NO actions were not exerted by cGMP signaling, as they were not mimicked by cGMP analogue nor blocked by inhibitors of guanylate cyclase and protein kinase G. NO potentiation of I(Na,cAMP) was broadly distributed among many other neurons of the feeding motor network in the buccal ganglion. However, NO did not affect a second type of I(Na,cAMP) found in locomotor neurons of the pedal ganglia. These results suggest that NO acts through a novel mechanism to regulate the gain of cAMP-dependent neuromodulatory pathways that activate I(Na,cAMP) and may thereby affect the set points of feeding network excitability and reactivity to exogenous input.
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Affiliation(s)
- Nathan G Hatcher
- Deprtment of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 414 Burrill Hall, 407 S. Goodwin Ave., Urbana, IL 61801, USA
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8
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Bichet DG. Lithium, cyclic AMP signaling, A-kinase anchoring proteins, and aquaporin-2. J Am Soc Nephrol 2006; 17:920-2. [PMID: 16540556 DOI: 10.1681/asn.2006020135] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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9
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Cooper DMF. Regulation and organization of adenylyl cyclases and cAMP. Biochem J 2003; 375:517-29. [PMID: 12940771 PMCID: PMC1223734 DOI: 10.1042/bj20031061] [Citation(s) in RCA: 276] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 08/07/2003] [Accepted: 08/26/2003] [Indexed: 11/17/2022]
Abstract
Adenylyl cyclases are a critically important family of multiply regulated signalling molecules. Their susceptibility to many modes of regulation allows them to integrate the activities of a variety of signalling pathways. However, this property brings with it the problem of imparting specificity and discrimination. Recent studies are revealing the range of strategies utilized by the cyclases to solve this problem. Microdomains are a consequence of these solutions, in which cAMP dynamics may differ from the broad cytosol. Currently evolving methodologies are beginning to reveal cAMP fluctuations in these various compartments.
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Affiliation(s)
- Dermot M F Cooper
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK.
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10
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Imendra KG, Miyamoto T, Okada Y, Toda K. Serotonin differentially modulates the electrical properties of different subsets of taste receptor cells in bullfrog. Eur J Neurosci 2002; 16:629-40. [PMID: 12270038 DOI: 10.1046/j.1460-9568.2002.02107.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serotonin (5-hydroxytryptamin, 5-HT) is localized in taste bud cells of vertebrates. Effects of the external application of 5-HT on the membrane currents of frog taste receptor cells (TRCs) were investigated using patch-clamp technique in whole-cell configuration. The 5-HT (0.1-1 micro m) and 5-HT1A receptor agonist (+/-)-8-OH-2-(D1-n-propyl-amino)tetralin (8-OH-DPAT) (1-20 micro m) inhibited both voltage-gated sodium current (INa) and voltage-gated potassium current (IK) in 50% of TRCs, but potentiated IK without any significant effect on INa in another subset of 18% of TRCs. Voltage-gated currents in the residual TRCs were not affected by 5-HT or 8-OH-DPAT. External application of 10 micro m forskolin and 300 micro m 8-cpt cAMP [8-(4-chlorophenylthio)adenosine 3':5'-cyclic monophosphate] mimicked the inhibitory effect of 5-HT and 8-OH-DPAT on IK and INa while internal dialysis with 50 micro m protein kinase A inhibitor prevented the 5-HT-mediated inhibitory effects on IK and INa in TRCs. Internal dialysis of TRCs with high Ca2+-pipette solution (1 micro m) increased the IK in 58% of TRCs. The 5-HT reversibly increased the [Ca2+]i in 17% of TRCs when measured by Ca2+-imaging using a Ca2+-sensitive dye (fura-2 AM). These results suggest that 5-HT differentially modulates the voltage-gated membrane currents in different subsets of TRCs.
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Affiliation(s)
- Kotapola G Imendra
- Integrative Sensory Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
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11
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Affiliation(s)
- J H Schwartz
- Center for Neurobiology and Behavior, Columbia University, College of Physicians and Surgeons, 722 West 168th Street, New York, NY 10032, USA.
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12
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Imendra KG, Fujiyama R, Miyamoto T, Okada Y, Sato T. Serotonin inhibits voltage-gated sodium current by cyclic adenosine monophosphate-dependent mechanism in bullfrog taste receptor cells. Neurosci Lett 2000; 294:151-4. [PMID: 11072137 DOI: 10.1016/s0304-3940(00)01567-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have investigated the effect of 5-hydroxytryptamine (serotonin) (5-HT) on the membrane properties of bullfrog taste receptor cells (TRCs) using patch-clamp technique. External application of 5-HT reversibly suppressed the voltage-gated Na(+) current (I(Na)) in about half of the TRCs sampled. The magnitude of suppression of peak I(Na) was dependent on the holding potential of the cell. Forskolin and cyclic adenosine monophosphate (cAMP) mimicked the suppressive effect of 5-HT on I(Na), but an internal protein kinase A-inhibitor potentiated I(Na). These results suggest that 5-HT suppresses I(Na) of bullfrog TRCs via protein kinase A-dependent phosphorylation, resulting in suppression of the excitability of bullfrog TRCs.
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Affiliation(s)
- K G Imendra
- Department of Physiology, Nagasaki University School of Dentistry, 1-7-1 Sakamoto, 852-8588, Nagasaki, Japan
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13
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Rich TC, Fagan KA, Nakata H, Schaack J, Cooper DM, Karpen JW. Cyclic nucleotide-gated channels colocalize with adenylyl cyclase in regions of restricted cAMP diffusion. J Gen Physiol 2000; 116:147-61. [PMID: 10919863 PMCID: PMC2229499 DOI: 10.1085/jgp.116.2.147] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyclic AMP is a ubiquitous second messenger that coordinates diverse cellular functions. Current methods for measuring cAMP lack both temporal and spatial resolution, leading to the pervasive notion that, unlike Ca(2+), cAMP signals are simple and contain little information. Here we show the development of adenovirus-expressed cyclic nucleotide-gated channels as sensors for cAMP. Homomultimeric channels composed of the olfactory alpha subunit responded rapidly to jumps in cAMP concentration, and their cAMP sensitivity was measured to calibrate the sensor for intracellular measurements. We used these channels to detect cAMP, produced by either heterologously expressed or endogenous adenylyl cyclase, in both single cells and cell populations. After forskolin stimulation, the endogenous adenylyl cyclase in C6-2B glioma cells produced high concentrations of cAMP near the channels, yet the global cAMP concentration remained low. We found that rapid exchange of the bulk cytoplasm in whole-cell patch clamp experiments did not prevent the buildup of significant levels of cAMP near the channels in human embryonic kidney 293 (HEK-293) cells expressing an exogenous adenylyl cyclase. These results can be explained quantitatively by a cell compartment model in which cyclic nucleotide-gated channels colocalize with adenylyl cyclase in microdomains, and diffusion of cAMP between these domains and the bulk cytosol is significantly hindered. In agreement with the model, we measured a slow rate of cAMP diffusion from the whole-cell patch pipette to the channels (90% exchange in 194 s, compared with 22-56 s for substances that monitor exchange with the cytosol). Without a microdomain and restricted diffusional access to the cytosol, we are unable to account for all of the results. It is worth noting that in models of unrestricted diffusion, even in extreme proximity to adenylyl cyclase, cAMP does not reach high enough concentrations to substantially activate PKA or cyclic nucleotide-gated channels, unless the entire cell fills with cAMP. Thus, the microdomains should facilitate rapid and efficient activation of both PKA and cyclic nucleotide-gated channels, and allow for local feedback control of adenylyl cyclase. Localized cAMP signals should also facilitate the differential regulation of cellular targets.
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Affiliation(s)
- Thomas C. Rich
- Department of Physiology and Biophysics, University of Colorado Health Sciences Center, Denver, CO 80262
| | - Kent A. Fagan
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80262
| | - Hiroko Nakata
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80262
| | - Jerome Schaack
- Department of Microbiology, University of Colorado Health Sciences Center, Denver, CO 80262
| | - Dermot M.F. Cooper
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80262
| | - Jeffrey W. Karpen
- Department of Physiology and Biophysics, University of Colorado Health Sciences Center, Denver, CO 80262
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14
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Sudlow LC, Jing J, Moroz LL, Gillette R. Serotonin immunoreactivity in the central nervous system of the marine molluscs
Pleurobranchaea californica
and
Tritonia diomedea. J Comp Neurol 1998. [DOI: 10.1002/(sici)1096-9861(19980615)395:4<466::aid-cne4>3.0.co;2-#] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Leland C. Sudlow
- Department of Molecular and Integrative Physiology and the Neuroscience Program, University of Illinois, Urbana‐Champaign, Urbana, Illinois 61801
| | - Jian Jing
- Department of Molecular and Integrative Physiology and the Neuroscience Program, University of Illinois, Urbana‐Champaign, Urbana, Illinois 61801
| | - Leonid L. Moroz
- Department of Molecular and Integrative Physiology and the Neuroscience Program, University of Illinois, Urbana‐Champaign, Urbana, Illinois 61801
| | - Rhanor Gillette
- Department of Molecular and Integrative Physiology and the Neuroscience Program, University of Illinois, Urbana‐Champaign, Urbana, Illinois 61801
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