1
|
Tichelman NL, Foerges AL, Elmenhorst EM, Lange D, Hennecke E, Baur DM, Beer S, Kroll T, Neumaier B, Bauer A, Landolt HP, Aeschbach D, Elmenhorst D. A genetic variation in the adenosine A2A receptor gene contributes to variability in oscillatory alpha power in wake and sleep EEG and A 1 adenosine receptor availability in the human brain. Neuroimage 2023; 280:120345. [PMID: 37625500 DOI: 10.1016/j.neuroimage.2023.120345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/25/2023] [Accepted: 08/22/2023] [Indexed: 08/27/2023] Open
Abstract
The EEG alpha rhythm (∼ 8-13 Hz) is one of the most salient human brain activity rhythms, modulated by the level of attention and vigilance and related to cerebral energy metabolism. Spectral power in the alpha range in wakefulness and sleep strongly varies among individuals based on genetic predisposition. Knowledge about the underlying genes is scarce, yet small studies indicated that the variant rs5751876 of the gene encoding A2A adenosine receptors (ADORA2A) may contribute to the inter-individual variation. The neuromodulator adenosine is directly linked to energy metabolism as product of adenosine tri-phosphate breakdown and acts as a sleep promoting molecule by activating A1 and A2A adenosine receptors. We performed sleep and positron emission tomography studies in 59 healthy carriers of different rs5751876 alleles, and quantified EEG oscillatory alpha power in wakefulness and sleep, as well as A1 adenosine receptor availability with 18F-CPFPX. Oscillatory alpha power was higher in homozygous C-allele carriers (n = 27, 11 females) compared to heterozygous and homozygous carriers of the T-allele (n(C/T) = 23, n(T/T) = 5, 13 females) (F(18,37) = 2.35, p = 0.014, Wilk's Λ = 0.487). Furthermore, a modulatory effect of ADORA2A genotype on A1 adenosine receptor binding potential was found across all considered brain regions (F(18,40) = 2.62, p = 0.006, Wilk's Λ = 0.459), which remained significant for circumscribed occipital region of calcarine fissures after correction for multiple comparisons. In female participants, a correlation between individual differences in oscillatory alpha power and A1 receptor availability was observed. In conclusion, we confirmed that a genetic variant of ADORA2A affects individual alpha power, while a direct modulatory effect via A1 adenosine receptors in females is suggested.
Collapse
Affiliation(s)
- Naemi L Tichelman
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Anna L Foerges
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany; RWTH Aachen University, Department of Neurophysiology, Institute of Zoology (Bio-II), Worringerweg 3, Aachen, North Rhine-Westphalia 52074, Germany
| | - Eva-Maria Elmenhorst
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany; Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen, North Rhine-Westphalia 52074, Germany
| | - Denise Lange
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany
| | - Eva Hennecke
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany
| | - Diego M Baur
- University of Zurich, Institute of Pharmacology & Toxicology, Winterthurerstrasse 190, Zurich 8057, Switzerland and Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - Simone Beer
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Tina Kroll
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-5), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Andreas Bauer
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany
| | - Hans-Peter Landolt
- University of Zurich, Institute of Pharmacology & Toxicology, Winterthurerstrasse 190, Zurich 8057, Switzerland and Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
| | - Daniel Aeschbach
- German Aerospace Center, Institute of Aerospace Medicine, Linder Höhe, Cologne, North Rhine-Westphalia 51147, Germany; Harvard Medical School, Division of Sleep Medicine, Suite BL-438, 221 Longwood Avenue, Boston, Massachusetts 02115, United States of America; Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Center, Sigmund-Freud Str. 25, Bonn, North Rhine-Westphalia 53127, Germany
| | - David Elmenhorst
- Forschungszentrum Jülich, Institute of Neuroscience and Medicine (INM-2), Wilhelm-Johnen-Strasse, Jülich, North Rhine-Westphalia 52428, Germany; Rheinische Friedrich-Wilhelms-Universität Bonn, Division of Medical Psychology, Venusberg-Campus 1, Bonn, North Rhine-Westphalia 53127, Germany; University Hospital Cologne, Multimodal Neuroimaging Group, Department of Nuclear Medicine, Kerpener Strasse 62, Cologne, North Rhine-Westphalia 50937, Germany.
| |
Collapse
|
2
|
Skilling QM, Eniwaye B, Clawson BC, Shaver J, Ognjanovski N, Aton SJ, Zochowski M. Acetylcholine-gated current translates wake neuronal firing rate information into a spike timing-based code in Non-REM sleep, stabilizing neural network dynamics during memory consolidation. PLoS Comput Biol 2021; 17:e1009424. [PMID: 34543284 PMCID: PMC8483332 DOI: 10.1371/journal.pcbi.1009424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 09/30/2021] [Accepted: 09/06/2021] [Indexed: 11/19/2022] Open
Abstract
Sleep is critical for memory consolidation, although the exact mechanisms mediating this process are unknown. Combining reduced network models and analysis of in vivo recordings, we tested the hypothesis that neuromodulatory changes in acetylcholine (ACh) levels during non-rapid eye movement (NREM) sleep mediate stabilization of network-wide firing patterns, with temporal order of neurons’ firing dependent on their mean firing rate during wake. In both reduced models and in vivo recordings from mouse hippocampus, we find that the relative order of firing among neurons during NREM sleep reflects their relative firing rates during prior wake. Our modeling results show that this remapping of wake-associated, firing frequency-based representations is based on NREM-associated changes in neuronal excitability mediated by ACh-gated potassium current. We also show that learning-dependent reordering of sequential firing during NREM sleep, together with spike timing-dependent plasticity (STDP), reconfigures neuronal firing rates across the network. This rescaling of firing rates has been reported in multiple brain circuits across periods of sleep. Our model and experimental data both suggest that this effect is amplified in neural circuits following learning. Together our data suggest that sleep may bias neural networks from firing rate-based towards phase-based information encoding to consolidate memories. We show that neuromodulatory changes during non-rapid eye movement (NREM) sleep generate stable spike timing relationships between neurons, the ordering of which reflects the neurons’ relative firing rates during wake. Learning-dependent ordering of firing in the hippocampus during NREM, acting in tandem with spike timing-dependent plasticity, reconfigures neuronal firing rates across the hippocampal network. This “rescaling” of neuronal firing rates has recently been reported in multiple brain circuits across periods of sleep. Together, our results suggest that the brain is remapping frequency-biased representations of information formed during wake into timing biased-representations during NREM sleep.
Collapse
Affiliation(s)
- Quinton M Skilling
- Biophysics Program, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bolaji Eniwaye
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Brittany C Clawson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - James Shaver
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Nicolette Ognjanovski
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michal Zochowski
- Biophysics Program, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Physics, University of Michigan, Ann Arbor, Michigan, United States of America
| |
Collapse
|
3
|
Combe CL, Gasparini S. I h from synapses to networks: HCN channel functions and modulation in neurons. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:119-132. [PMID: 34181891 DOI: 10.1016/j.pbiomolbio.2021.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/25/2021] [Accepted: 06/03/2021] [Indexed: 01/16/2023]
Abstract
Hyperpolarization-activated cyclic nucleotide gated (HCN) channels and the current they carry, Ih, are widely and diversely distributed in the central nervous system (CNS). The distribution of the four subunits of HCN channels is variable within the CNS, within brain regions, and often within subcellular compartments. The precise function of Ih can depend heavily on what other channels are co-expressed. In this review, we give an overview of HCN channel structure, distribution, and modulation by cyclic adenosine monophosphate (cAMP). We then discuss HCN channel and Ih functions, where we have parsed the roles into two main effects: a steady effect on maintaining the resting membrane potential at relatively depolarized values, and slow channel dynamics. Within this framework, we discuss Ih involvement in resonance, synaptic integration, transmitter release, plasticity, and point out a special case, where the effects of Ih on the membrane potential and its slow channel dynamics have dual roles in thalamic neurons.
Collapse
Affiliation(s)
- Crescent L Combe
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Sonia Gasparini
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA.
| |
Collapse
|
4
|
Mamelak M. Sleep, Narcolepsy, and Sodium Oxybate. Curr Neuropharmacol 2021; 20:272-291. [PMID: 33827411 PMCID: PMC9413790 DOI: 10.2174/1570159x19666210407151227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 11/23/2022] Open
Abstract
Sodium oxybate (SO) has been in use for many decades to treat narcolepsy with cataplexy. It functions as a weak GABAB agonist but also as an energy source for the brain as a result of its metabolism to succinate and as a powerful antioxidant because of its capacity to induce the formation of NADPH. Its actions at thalamic GABAB receptors can induce slow-wave activity, while its actions at GABAB receptors on monoaminergic neurons can induce or delay REM sleep. By altering the balance between monoaminergic and cholinergic neuronal activity, SO uniquely can induce and prevent cataplexy. The formation of NADPH may enhance sleep’s restorative process by accelerating the removal of the reactive oxygen species (ROS), which accumulate during wakefulness. SO improves alertness in normal subjects and in patients with narcolepsy. SO may allay severe psychological stress - an inflammatory state triggered by increased levels of ROS and characterized by cholinergic supersensitivity and monoaminergic deficiency. SO may be able to eliminate the inflammatory state and correct the cholinergic/ monoaminergic imbalance.
Collapse
Affiliation(s)
- Mortimer Mamelak
- Department of Psychiatry, Baycrest Hospital, University of Toronto, Toronto, Ontario. Canada
| |
Collapse
|
5
|
Desai NV, Varela C. Distinct burst properties contribute to the functional diversity of thalamic nuclei. J Comp Neurol 2021; 529:3726-3750. [PMID: 33723858 PMCID: PMC8440663 DOI: 10.1002/cne.25141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022]
Abstract
Thalamic neurons fire spikes in two modes, burst and tonic. The function of burst firing is unclear, but the evidence suggests that bursts are more effective at activating cortical cells, and that postinhibition rebound bursting contributes to thalamocortical oscillations during sleep. Bursts are considered stereotyped signals; however, there is limited evidence regarding how burst properties compare across thalamic nuclei of different functional or anatomical organization. Here, we used whole-cell patch clamp recordings and compartmental modeling to investigate the properties of bursts in six sensory thalamic nuclei, to study the mechanisms that can lead to different burst properties, and to assess the implications of different burst properties for thalamocortical transmission and oscillatory functions. We found that bursts in higher-order cells on average had higher number of spikes and longer latency to the first spike. Additionally, burst features in first-order neurons were determined by sensory modality. Shifting the voltage-dependence and density of the T-channel conductance in a compartmental model replicates the burst properties from the intracellular recordings, pointing to molecular mechanisms that can generate burst diversity. Furthermore, the model predicts that bursts with higher number of spikes will drastically reduce the effectiveness of thalamocortical transmission. In addition, the latency to burst limited the rebound oscillatory frequency in modeled cells. These results demonstrate that burst properties vary according to the thalamocortical hierarchy and with sensory modality. The findings imply that, while in burst mode, thalamocortical transmission and firing frequency will be determined by the number of spikes and latency to burst.
Collapse
Affiliation(s)
- Nidhi Vasant Desai
- Psychology Department, Jupiter Life Sciences Initiative, Florida Atlantic University, Boca Raton, Florida, USA
| | - Carmen Varela
- Psychology Department, Jupiter Life Sciences Initiative, Florida Atlantic University, Boca Raton, Florida, USA
| |
Collapse
|
6
|
Lazarus M, Oishi Y, Bjorness TE, Greene RW. Gating and the Need for Sleep: Dissociable Effects of Adenosine A 1 and A 2A Receptors. Front Neurosci 2019; 13:740. [PMID: 31379490 PMCID: PMC6650574 DOI: 10.3389/fnins.2019.00740] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 07/02/2019] [Indexed: 12/20/2022] Open
Abstract
Roughly one-third of the human lifetime is spent in sleep, yet the reason for sleep remains unclear. Understanding the physiologic function of sleep is crucial toward establishing optimal health. Several proposed concepts address different aspects of sleep physiology, including humoral and circuit-based theories of sleep-wake regulation, the homeostatic two-process model of sleep regulation, the theory of sleep as a state of adaptive inactivity, and observations that arousal state and sleep homeostasis can be dissociated in pathologic disorders. Currently, there is no model that places the regulation of arousal and sleep homeostasis in a unified conceptual framework. Adenosine is well known as a somnogenic substance that affects normal sleep-wake patterns through several mechanisms in various brain locations via A1 or A2A receptors (A1Rs or A2ARs). Many cells and processes appear to play a role in modulating the extracellular concentration of adenosine at neuronal A1R or A2AR sites. Emerging evidence suggests that A1Rs and A2ARs have different roles in the regulation of sleep. In this review, we propose a model in which A2ARs allow the brain to sleep, i.e., these receptors provide sleep gating, whereas A1Rs modulate the function of sleep, i.e., these receptors are essential for the expression and resolution of sleep need. In this model, sleep is considered a brain state established in the absence of arousing inputs.
Collapse
Affiliation(s)
- Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Yo Oishi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Theresa E Bjorness
- Research and Development, VA North Texas Health Care System, Dallas, TX, United States.,Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Robert W Greene
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan.,Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| |
Collapse
|
7
|
Zobeiri M, Chaudhary R, Datunashvili M, Heuermann RJ, Lüttjohann A, Narayanan V, Balfanz S, Meuth P, Chetkovich DM, Pape HC, Baumann A, van Luijtelaar G, Budde T. Modulation of thalamocortical oscillations by TRIP8b, an auxiliary subunit for HCN channels. Brain Struct Funct 2018; 223:1537-1564. [PMID: 29168010 PMCID: PMC5869905 DOI: 10.1007/s00429-017-1559-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/30/2017] [Indexed: 12/16/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels have important functions in controlling neuronal excitability and generating rhythmic oscillatory activity. The role of tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) in regulation of hyperpolarization-activated inward current, I h, in the thalamocortical system and its functional relevance for the physiological thalamocortical oscillations were investigated. A significant decrease in I h current density, in both thalamocortical relay (TC) and cortical pyramidal neurons was found in TRIP8b-deficient mice (TRIP8b-/-). In addition basal cAMP levels in the brain were found to be decreased while the availability of the fast transient A-type K+ current, I A, in TC neurons was increased. These changes were associated with alterations in intrinsic properties and firing patterns of TC neurons, as well as intrathalamic and thalamocortical network oscillations, revealing a significant increase in slow oscillations in the delta frequency range (0.5-4 Hz) during episodes of active-wakefulness. In addition, absence of TRIP8b suppresses the normal desynchronization response of the EEG during the switch from slow-wave sleep to wakefulness. It is concluded that TRIP8b is necessary for the modulation of physiological thalamocortical oscillations due to its direct effect on HCN channel expression in thalamus and cortex and that mechanisms related to reduced cAMP signaling may contribute to the present findings.
Collapse
Affiliation(s)
- Mehrnoush Zobeiri
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany.
| | - Rahul Chaudhary
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Maia Datunashvili
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Robert J Heuermann
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, 60611Chicago, USA
| | - Annika Lüttjohann
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Venu Narayanan
- Department of Neurology and Institute of Translational Neurology, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Sabine Balfanz
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Patrick Meuth
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, 60611Chicago, USA
| | - Hans-Christian Pape
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Arnd Baumann
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | | | - Thomas Budde
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany.
| |
Collapse
|
8
|
Greene RW, Bjorness TE, Suzuki A. The adenosine-mediated, neuronal-glial, homeostatic sleep response. Curr Opin Neurobiol 2017. [PMID: 28633050 DOI: 10.1016/j.conb.2017.05.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Slow wave activity (SWA) during slow wave sleep (SWS) is the best indicator of the sleep homeostasis. The intensity of the SWA observed during SWS that follows prolonged waking is directly correlated with the duration of prior waking and its intensity decays during SWS suggesting a buildup and a resolution of sleep need. This sleep-homeostasis related SWA results from a buildup and decay of extracellular adenosine that acts at neuronal adenosine A1 receptors to facilitate SWA and is metabolized by adenosine kinase found in glia. This local neuronal-glial circuit for homeostatic SWA is primarily under the requisite control of two genes, the Adora1 and Adk, encoding the responsible adenosine receptor and adenosine's highest affinity metabolizing enzyme.
Collapse
Affiliation(s)
- Robert W Greene
- UT Southwestern Medical Center, Dallas, TX, United States; International Institute of Integrative Sleep Medicine, University of Tsukuba, Japan; VAMC, Dallas, TX, United States.
| | - Theresa E Bjorness
- UT Southwestern Medical Center, Dallas, TX, United States; VAMC, Dallas, TX, United States
| | - Ayako Suzuki
- UT Southwestern Medical Center, Dallas, TX, United States
| |
Collapse
|
9
|
An Adenosine-Mediated Glial-Neuronal Circuit for Homeostatic Sleep. J Neurosci 2016; 36:3709-21. [PMID: 27030757 DOI: 10.1523/jneurosci.3906-15.2016] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/15/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Sleep homeostasis reflects a centrally mediated drive for sleep, which increases during waking and resolves during subsequent sleep. Here we demonstrate that mice deficient for glial adenosine kinase (AdK), the primary metabolizing enzyme for adenosine (Ado), exhibit enhanced expression of this homeostatic drive by three independent measures: (1) increased rebound of slow-wave activity; (2) increased consolidation of slow-wave sleep; and (3) increased time constant of slow-wave activity decay during an average slow-wave sleep episode, proposed and validated here as a new index for homeostatic sleep drive. Conversely, mice deficient for the neuronal adenosine A1 receptor exhibit significantly decreased sleep drive as judged by these same indices. Neuronal knock-out of AdK did not influence homeostatic sleep need. Together, these findings implicate a glial-neuronal circuit mediated by intercellular Ado, controlling expression of homeostatic sleep drive. Because AdK is tightly regulated by glial metabolic state, our findings suggest a functional link between cellular metabolism and sleep homeostasis. SIGNIFICANCE STATEMENT The work presented here provides evidence for an adenosine-mediated regulation of sleep in response to waking (i.e., homeostatic sleep need), requiring activation of neuronal adenosine A1 receptors and controlled by glial adenosine kinase. Adenosine kinase acts as a highly sensitive and important metabolic sensor of the glial ATP/ADP and AMP ratio directly controlling intracellular adenosine concentration. Glial equilibrative adenosine transporters reflect the intracellular concentration to the extracellular milieu to activate neuronal adenosine receptors. Thus, adenosine mediates a glial-neuronal circuit linking glial metabolic state to neural-expressed sleep homeostasis. This indicates a metabolically related function(s) for this glial-neuronal circuit in the buildup and resolution of our need to sleep and suggests potential therapeutic targets more directly related to sleep function.
Collapse
|
10
|
Goitia B, Rivero-Echeto MC, Weisstaub NV, Gingrich JA, Garcia-Rill E, Bisagno V, Urbano FJ. Modulation of GABA release from the thalamic reticular nucleus by cocaine and caffeine: role of serotonin receptors. J Neurochem 2015; 136:526-35. [PMID: 26484945 DOI: 10.1111/jnc.13398] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/23/2015] [Accepted: 10/02/2015] [Indexed: 11/30/2022]
Abstract
Serotonin receptors are targets of drug therapies for a variety of neuropsychiatric and neurodegenerative disorders. Cocaine inhibits the re-uptake of serotonin (5-HT), dopamine, and noradrenaline, whereas caffeine blocks adenosine receptors and opens ryanodine receptors in the endoplasmic reticulum. We studied how 5-HT and adenosine affected spontaneous GABAergic transmission from thalamic reticular nucleus. We combined whole-cell patch clamp recordings of miniature inhibitory post-synaptic currents (mIPSCs) in ventrobasal thalamic neurons during local (puff) application of 5-HT in wild type (WT) or knockout mice lacking 5-HT2A receptors (5-HT2A -/-). Inhibition of mIPSCs frequency by low (10 μM) and high (100 μM) 5-HT concentrations was observed in ventrobasal neurons from 5-HT2A -/- mice. In WT mice, only 100 μM 5-HT significantly reduced mIPSCs frequency. In 5-HT2A -/- mice, NAN-190, a specific 5-HT1A antagonist, prevented the 100 μM 5-HT inhibition while blocking H-currents that prolonged inhibition during post-puff periods. The inhibitory effects of 100 μM 5-HT were enhanced in cocaine binge-treated 5-HT2A -/- mice. Caffeine binge treatment did not affect 5-HT-mediated inhibition. Our findings suggest that both 5-HT1A and 5-HT2A receptors are present in pre-synaptic thalamic reticular nucleus terminals. Serotonergic-mediated inhibition of GABA release could underlie aberrant thalamocortical physiology described after repetitive consumption of cocaine. Our findings suggest that both 5-HT1A , 5-HT2A and A1 receptors are present in pre-synaptic TRN terminals. 5-HT1A and A1 receptors would down-regulate adenylate cyclase, whereas 5-HT1A would also increase the probability of the opening of G-protein-activated inwardly rectifying K(+) channels (GIRK). Sustained opening of GIRK channels would hyperpolarize pre-synaptic terminals activating H-currents, resulting in less GABA release. 5-HT2A -would activate PLC and IP3 , increasing intracellular [Ca(2+) ] and thus facilitating GABA release.
Collapse
Affiliation(s)
- Belén Goitia
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina.,Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - María Celeste Rivero-Echeto
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina.,Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Noelia V Weisstaub
- Grupo de Neurociencia de Sistemas, Departamento de Fisiología, Facultad de Medicina, Instituto de Fisiología y Biofísica (IFIBIO), UBA, Ciudad de Buenos Aires, Argentina
| | - Jay A Gingrich
- Division of Developmental Neuroscience, Columbia University and the NYSPI, Sackler Institute for Developmental Psychobiology, New York City, New York, USA
| | - Edgar Garcia-Rill
- Department of Neurobiology and Developmental Sciences, Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Verónica Bisagno
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Francisco J Urbano
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado" (DFBMC) Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Universidad de Buenos Aires, Ciudad Universitaria, Ciudad de Buenos Aires, Argentina
| |
Collapse
|
11
|
Yang YC, Hu CC, Lai YC. Non-additive modulation of synaptic transmission by serotonin, adenosine, and cholinergic modulators in the sensory thalamus. Front Cell Neurosci 2015; 9:60. [PMID: 25852468 PMCID: PMC4360759 DOI: 10.3389/fncel.2015.00060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/09/2015] [Indexed: 11/13/2022] Open
Abstract
The thalamus relays sensory information to the cortex. Oscillatory activities of the thalamocortical network are modulated by monoamines, acetylcholine, and adenosine, and could be the key features characteristic of different vigilance states. Although the thalamus is almost always subject to the actions of more than just one neuromodulators, reports on the modulatory effect of coexisting neuromodulators on thalamic synaptic transmission are unexpectedly scarce. We found that, if present alone, monoamine or adenosine decreases retinothalamic synaptic strength and short-term depression, whereas cholinergic modulators generally enhance postsynaptic response to presynaptic activity. However, coexistence of different modulators tends to produce non-additive effect, not predictable based on the action of individual modulators. Acetylcholine, acting via nicotinic receptors, can interact with either serotonin or adenosine to abolish most short-term synaptic depression. Moreover, the coexistence of adenosine and monoamine, with or without acetylcholine, results in robustly decreased synaptic strength and transforms short-term synaptic depression to facilitation. These findings are consistent with a view that acetylcholine is essential for an "enriched" sensory flow through the thalamus, and the flow is trimmed down by concomitant monoamine or adenosine (presumably for the wakefulness and rapid-eye movement, or REM, sleep states, respectively). In contrast, concomitant adenosine and monoamine would lead to a markedly "deprived" (and high-pass filtered) sensory flow, and thus the dramatic decrease of monoamine may constitute the basic demarcation between non-REM and REM sleep. The collective actions of different neuromodulators on thalamic synaptic transmission thus could be indispensable for the understanding of network responsiveness in different vigilance states.
Collapse
Affiliation(s)
- Ya-Chin Yang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan ; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan
| | - Chun-Chang Hu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan ; Department of Neurosurgery, Chang-Gung Memorial Hospital Linkou, Taiwan
| | - Yi-Chen Lai
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan
| |
Collapse
|
12
|
Paek SB, Min HK, Kim I, Knight EJ, Baek JJ, Bieber AJ, Lee KH, Chang SY. Frequency-dependent functional neuromodulatory effects on the motor network by ventral lateral thalamic deep brain stimulation in swine. Neuroimage 2014; 105:181-8. [PMID: 25451479 DOI: 10.1016/j.neuroimage.2014.09.064] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/03/2014] [Accepted: 09/27/2014] [Indexed: 01/07/2023] Open
Abstract
Thalamic deep brain stimulation (DBS) is an FDA-approved neurosurgical treatment for medication-refractory essential tremor. Its therapeutic benefit is highly dependent upon stimulation frequency and voltage parameters. We investigated these stimulation parameter-dependent effects on neural network activation by performing functional magnetic resonance imaging (fMRI) during DBS of the ventral lateral (VL) thalamus and comparing the blood oxygenation level-dependent (BOLD) signals induced by multiple stimulation parameter combinations in a within-subject study of swine. Low (10 Hz) and high (130 Hz) frequency stimulation was applied at 3, 5, and 7 V in the VL thalamus of normal swine (n = 5). We found that stimulation frequency and voltage combinations differentially modulated the brain network activity in the sensorimotor cortex, the basal ganglia, and the cerebellum in a parameter-dependent manner. Notably, in the motor cortex, high frequency stimulation generated a negative BOLD response, while low frequency stimulation increased the positive BOLD response. These frequency-dependent differential effects suggest that the VL thalamus is an exemplary target for investigating functional network connectivity associated with therapeutic DBS.
Collapse
Affiliation(s)
- Seungleal B Paek
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Inyong Kim
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Emily J Knight
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - James J Baek
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Allan J Bieber
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
| | - Su-Youne Chang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
| |
Collapse
|
13
|
Response of human thalamic neurons to high-frequency stimulation. PLoS One 2014; 9:e96026. [PMID: 24804767 PMCID: PMC4013084 DOI: 10.1371/journal.pone.0096026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 04/02/2014] [Indexed: 11/20/2022] Open
Abstract
Thalamic deep brain stimulation (DBS) is an effective treatment for tremor, but the mechanisms of action remain unclear. Previous studies of human thalamic neurons to noted transient rebound bursting activity followed by prolonged inhibition after cessation of high frequency extracellular stimulation, and the present study sought to identify the mechanisms underlying this response. Recordings from 13 thalamic neurons exhibiting low threshold spike (LTS) bursting to brief periods of extracellular stimulation were made during surgeries to implant DBS leads in 6 subjects with Parkinson's disease. The response immediately after cessation of stimulation included a short epoch of burst activity, followed by a prolonged period of silence before a return to LTS bursting. A computational model of a population of thalamocortical relay neurons and presynaptic axons terminating on the neurons was used to identify cellular mechanisms of the observed responses. The model included the actions of neuromodulators through inhibition of a non-pertussis toxin sensitive K+ current (IKL), activation of a pertussis toxin sensitive K+ current (IKG), and a shift in the activation curve of the hyperpolarization-activated cation current (Ih). The model replicated well the measured responses, and the prolonged inhibition was associated most strongly with changes in IKG while modulation of IKL or Ih had minimal effects on post-stimulus inhibition suggesting that neuromodulators released in response to high frequency stimulation are responsible for mediating the post-stimulation bursting and subsequent long duration silence of thalamic neurons. The modeling also indicated that the axons of the model neurons responded robustly to suprathreshold stimulation despite the inhibitory effects on the soma. The findings suggest that during DBS the axons of thalamocortical neurons are activated while the cell bodies are inhibited thus blocking the transmission of pathological signals through the network and replacing them with high frequency regular firing.
Collapse
|
14
|
Yang YC, Hu CC, Huang CS, Chou PY. Thalamic synaptic transmission of sensory information modulated by synergistic interaction of adenosine and serotonin. J Neurochem 2013; 128:852-63. [DOI: 10.1111/jnc.12499] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Ya-Chin Yang
- Department of Biomedical Sciences; College of Medicine, Chang Gung University; Tao-Yuan Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine; Chang Gung University; Tao-Yuan Taiwan
| | - Chun-Chang Hu
- Graduate Institute of Biomedical Sciences, College of Medicine; Chang Gung University; Tao-Yuan Taiwan
| | - Chen-Syuan Huang
- Department of Biomedical Sciences; College of Medicine, Chang Gung University; Tao-Yuan Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine; Chang Gung University; Tao-Yuan Taiwan
| | - Pei-Yu Chou
- Graduate Institute of Biomedical Sciences, College of Medicine; Chang Gung University; Tao-Yuan Taiwan
| |
Collapse
|
15
|
Huberfeld G, Le Duigou C, Le Van Quyen M, Navarro V, Baulac M, Miles R. The paradox of the paroxysm: can seizure precipitants help explain human ictogenesis? Neuroscientist 2013; 19:523-40. [PMID: 23881918 DOI: 10.1177/1073858413497430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An epileptic brain is permanently in a diseased state, but seizures occur rarely and without warning. Here we examine this paradox, common to paroxysmal diseases. We review the problem in the context of the prototypic acquired epilepsies of the medial temporal lobe. We ask how an epileptic temporal lobe differs from a healthy one and examine biological mechanisms that may explain the transition to seizure. Attempts to predict seizure timing from analyses of brain electrical activity suggest that the neurological processes involved may be initiated significantly before a seizure. Furthermore, whereas seizures are said to occur without warning, some patients say they know when a seizure is imminent. Several factors, including sleep deprivation, oscillations in hormonal levels, or withdrawal from drugs, increase the probability of a seizure. We ask whether these seizure precipitants might act through common neuronal mechanisms. Several precipitating factors seem to involve relief from a neurosteroid modulation of gamma-amino butyric acid receptor type A (GABAA) receptors. We propose tests of this hypothesis.
Collapse
Affiliation(s)
- Gilles Huberfeld
- INSERM U975, Institut du Cerveau et la Moëlle Epinière, Paris, France
| | | | | | | | | | | |
Collapse
|
16
|
Lüthi A. The Adenosine Story Goes Ionic: CaV2.1-type Ca2+ Channels Identified as Effectors of Adenosine's Somnogenic Actions. Sleep 2013; 36:13-4. [DOI: 10.5665/sleep.2290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
17
|
Chang SY, Kim I, Marsh MP, Jang DP, Hwang SC, Van Gompel JJ, Goerss SJ, Kimble CJ, Bennet KE, Garris PA, Blaha CD, Lee KH. Wireless fast-scan cyclic voltammetry to monitor adenosine in patients with essential tremor during deep brain stimulation. Mayo Clin Proc 2012; 87:760-5. [PMID: 22809886 PMCID: PMC3538486 DOI: 10.1016/j.mayocp.2012.05.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 11/29/2022]
Abstract
Essential tremor is often markedly reduced during deep brain stimulation simply by implanting the stimulating electrode before activating neurostimulation. Referred to as the microthalamotomy effect, the mechanisms of this unexpected consequence are thought to be related to microlesioning targeted brain tissue, that is, a microscopic version of tissue ablation in thalamotomy. An alternate possibility is that implanting the electrode induces immediate neurochemical release. Herein, we report the experiment performing with real-time fast-scan cyclic voltammetry to quantify neurotransmitter concentrations in human subjects with essential tremor during deep brain stimulation. The results show that the microthalamotomy effect is accompanied by local neurochemical changes, including adenosine release.
Collapse
Affiliation(s)
- Su-Youne Chang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN
| | - Inyong Kim
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
| | | | - Dong Pyo Jang
- Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
| | - Sun-Chul Hwang
- Department of Neurosurgery, Soonchunhyang University, Bucheon Hospital, Bucheon, South Korea
| | | | | | | | | | - Paul A. Garris
- School of Biological Sciences, Illinois State University, Normal, IL
| | | | - Kendall H. Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN
- Correspondence: Address to Kendall H. Lee, MD, PhD, Department of Neurologic Surgery and Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| |
Collapse
|
18
|
Li Y, Fan S, Yan J, Li B, Chen F, Xia J, Yu Z, Hu Z. Adenosine modulates the excitability of layer II stellate neurons in entorhinal cortex through A1 receptors. Hippocampus 2012; 21:265-80. [PMID: 20054814 DOI: 10.1002/hipo.20745] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Stellate neurons in layer II entorhinal cortex (EC) provide the main output from the EC to the hippocampus. It is believed that adenosine plays a crucial role in neuronal excitability and synaptic transmission in the CNS, however, the function of adenosine in the EC is still elusive. Here, the data reported showed that adenosine hyperpolarized stellate neurons in a concentration-dependent manner, accompanied by a decrease in firing frequency. This effect corresponded to the inhibition of the hyperpolarization-activated, cation nonselective (HCN) channels. Surprisingly, the adenosine-induced inhibition was blocked by 3 μM 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective A(1) receptor antagonists, but not by 10 μM 3,7-dimethyl-1-propargylxanthine (DMPX), a selective A(2) receptor antagonists, indicating that activation of adenosine A(1) receptors were responsible for the direct inhibition. In addition, adenosine reduced the frequency but not the amplitude of miniature EPSCs and IPSCs, suggesting that the global depression of glutamatergic and GABAergic transmission is mediated by a decrease in glutamate and GABA release, respectively. Again the presynaptic site of action was mediated by adenosine A(1) receptors. Furthermore, inhibition of spontaneous glutamate and GABA release by adenosine A(1) receptor activation was mediated by voltage-dependent Ca(2+) channels and extracellular Ca(2+) . Therefore, these findings revealed direct and indirect mechanisms by which activation of adenosine A(1) receptors on the cell bodies of stellate neurons and on the presynaptic terminals could regulate the excitability of these neurons.
Collapse
Affiliation(s)
- Yang Li
- Department of Physiology, Third Military Medical University, Chongqing, China
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Birdno MJ, Kuncel AM, Dorval AD, Turner DA, Gross RE, Grill WM. Stimulus features underlying reduced tremor suppression with temporally patterned deep brain stimulation. J Neurophysiol 2011; 107:364-83. [PMID: 21994263 DOI: 10.1152/jn.00906.2010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Deep brain stimulation (DBS) provides dramatic tremor relief when delivered at high-stimulation frequencies (more than ∼100 Hz), but its mechanisms of action are not well-understood. Previous studies indicate that high-frequency stimulation is less effective when the stimulation train is temporally irregular. The purpose of this study was to determine the specific characteristics of temporally irregular stimulus trains that reduce their effectiveness: long pauses, bursts, or irregularity per se. We isolated these characteristics in stimulus trains and conducted intraoperative measurements of postural tremor in eight volunteers. Tremor varied significantly across stimulus conditions (P < 0.015), and stimulus trains with pauses were significantly less effective than stimulus trains without (P < 0.002). There were no significant differences in tremor between trains with or without bursts or between trains that were irregular or periodic. Thus the decreased effectiveness of temporally irregular DBS trains is due to long pauses in the stimulus trains, not the degree of temporal irregularity alone. We also conducted computer simulations of neuronal responses to the experimental stimulus trains using a biophysical model of the thalamic network. Trains that suppressed tremor in volunteers also suppressed fluctuations in thalamic transmembrane potential at the frequency associated with cerebellar burst-driver inputs. Clinical and computational findings indicate that DBS suppresses tremor by masking burst-driver inputs to the thalamus and that pauses in stimulation prevent such masking. Although stimulation of other anatomic targets may provide tremor suppression, we propose that the most relevant neuronal targets for effective tremor suppression are the afferent cerebellar fibers that terminate in the thalamus.
Collapse
Affiliation(s)
- Merrill J Birdno
- Duke Univ., Dept. of Biomedical Engineering, Hudson Hall, Rm. 136, Box 90281, Durham, NC 27708-0281, USA
| | | | | | | | | | | |
Collapse
|
20
|
Differential regulation of HCN channel isoform expression in thalamic neurons of epileptic and non-epileptic rat strains. Neurobiol Dis 2011; 45:450-61. [PMID: 21945537 DOI: 10.1016/j.nbd.2011.08.032] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/25/2011] [Accepted: 08/23/2011] [Indexed: 02/07/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels represent the molecular substrate of the hyperpolarization-activated inward current (I(h)). Although these channels act as pacemakers for the generation of rhythmic activity in the thalamocortical network during sleep and epilepsy, their developmental profile in the thalamus is not yet fully understood. Here we combined electrophysiological, immunohistochemical, and mathematical modeling techniques to examine HCN gene expression and I(h) properties in thalamocortical relay (TC) neurons of the dorsal part of the lateral geniculate nucleus (dLGN) in an epileptic (WAG/Rij) compared to a non-epileptic (ACI) rat strain. Recordings of TC neurons between postnatal day (P) 7 and P90 in both rat strains revealed that I(h) was characterized by higher current density, more hyperpolarized voltage dependence, faster activation kinetics, and reduced cAMP-sensitivity in epileptic animals. All four HCN channel isoforms (HCN1-4) were detected in dLGN, and quantitative analyses revealed a developmental increase of protein expression of HCN1, HCN2, and HCN4 but a decrease of HCN3. HCN1 was expressed at higher levels in WAG/Rij rats, a finding that was correlated with increased expression of the interacting proteins filamin A (FilA) and tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). Analysis of a simplified computer model of the thalamic network revealed that the alterations of I(h) found in WAG/Rij rats compensate each other in a way that leaves I(h) availability constant, an effect that ensures unaltered cellular burst activity and thalamic oscillations. These data indicate that during postnatal developmental the hyperpolarizing shift in voltage dependency (resulting in less current availability) is compensated by an increase in current density in WAG/Rij thereby possibly limiting the impact of I(h) on epileptogenesis. Because HCN3 is expressed higher in young versus older animals, HCN3 likely does not contribute to alterations in I(h) in older animals.
Collapse
|
21
|
The sleep relay--the role of the thalamus in central and decentral sleep regulation. Pflugers Arch 2011; 463:53-71. [PMID: 21912835 DOI: 10.1007/s00424-011-1014-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/08/2011] [Accepted: 08/11/2011] [Indexed: 10/17/2022]
Abstract
Surprisingly, the concept of sleep, its necessity and function, the mechanisms of action, and its elicitors are far from being completely understood. A key to sleep function is to determine how and when sleep is induced. The aim of this review is to merge the classical concepts of central sleep regulation by the brainstem and hypothalamus with the recent findings on decentral sleep regulation in local neuronal assemblies and sleep regulatory substances that create a scenario in which sleep is both local and use dependent. The interface between these concepts is provided by thalamic cellular and network mechanisms that support rhythmogenesis of sleep-related activity. The brainstem and the hypothalamus centrally set the pace for sleep-related activity throughout the brain. Decentral regulation of the sleep-wake cycle was shown in the cortex, and the homeostat of non-rapid-eye-movement sleep is made up by molecular networks of sleep regulatory substances, allowing individual neurons or small neuronal assemblies to enter sleep-like states. Thalamic neurons provide state-dependent gating of sensory information via their ability to produce different patterns of electrogenic activity during wakefulness and sleep. Many mechanisms of sleep homeostasis or sleep-like states of neuronal assemblies, e.g. by the action of adenosine, can also be found in thalamic neurons, and we summarize cellular and network mechanisms of the thalamus that may elicit non-REM sleep. It is argued that both central and decentral regulators ultimately target the thalamus to induce global sleep-related oscillatory activity. We propose that future studies should integrate ideas of central, decentral, and thalamic sleep generation.
Collapse
|
22
|
Tawfik VL, Chang SY, Hitti FL, Roberts DW, Leiter JC, Jovanovic S, Lee KH. Deep brain stimulation results in local glutamate and adenosine release: investigation into the role of astrocytes. Neurosurgery 2011; 67:367-75. [PMID: 20644423 DOI: 10.1227/01.neu.0000371988.73620.4c] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Several neurological disorders are treated with deep brain stimulation; however, the mechanism underlying its ability to abolish oscillatory phenomena associated with diseases as diverse as Parkinson's disease and epilepsy remain largely unknown. OBJECTIVE To investigate the role of specific neurotransmitters in deep brain stimulation and determine the role of non-neuronal cells in its mechanism of action. METHODS We used the ferret thalamic slice preparation in vitro, which exhibits spontaneous spindle oscillations, to determine the effect of high-frequency stimulation on neurotransmitter release. We then performed experiments using an in vitro astrocyte culture to investigate the role of glial transmitter release in high-frequency stimulation-mediated abolishment of spindle oscillations. RESULTS In this series of experiments, we demonstrated that glutamate and adenosine release in ferret slices was able to abolish spontaneous spindle oscillations. The glutamate release was still evoked in the presence of the Na channel blocker tetrodotoxin, but was eliminated with the vesicular H-ATPase inhibitor bafilomycin and the calcium chelator 2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester. Furthermore, electrical stimulation of purified primary astrocytic cultures was able to evoke intracellular calcium transients and glutamate release, and bath application of 2-bis (2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester inhibited glutamate release in this setting. CONCLUSION Vesicular astrocytic neurotransmitter release may be an important mechanism by which deep brain stimulation is able to achieve clinical benefits.
Collapse
Affiliation(s)
- Vivianne L Tawfik
- Department of Pharmacology, Dartmouth Medical School, Hanover, New Hampshire, USA
| | | | | | | | | | | | | |
Collapse
|
23
|
Hughes SW, Lorincz ML, Parri HR, Crunelli V. Infraslow (<0.1 Hz) oscillations in thalamic relay nuclei basic mechanisms and significance to health and disease states. PROGRESS IN BRAIN RESEARCH 2011; 193:145-62. [PMID: 21854961 PMCID: PMC3173874 DOI: 10.1016/b978-0-444-53839-0.00010-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the absence of external stimuli, the mammalian brain continues to display a rich variety of spontaneous activity. Such activity is often highly stereotypical, is invariably rhythmic, and can occur with periodicities ranging from a few milliseconds to several minutes. Recently, there has been a particular resurgence of interest in fluctuations in brain activity occurring at < 0.1 Hz, commonly referred to as very slow or infraslow oscillations (ISOs). Whilst this is primarily due to the emergence of functional magnetic resonance imaging (fMRI) as a technique which has revolutionized the study of human brain dynamics, it is also a consequence of the application of full band electroencephalography (fbEEG). Despite these technical advances, the precise mechanisms which lead to ISOs in the brain remain unclear. In a host of animal studies, one brain region that consistently shows oscillations at < 0.1 Hz is the thalamus. Importantly, similar oscillations can also be observed in slices of isolated thalamic relay nuclei maintained in vitro. Here, we discuss the nature and mechanisms of these oscillations, paying particular attention to a potential role for astrocytes in their genesis. We also highlight the relationship between this activity and ongoing local network oscillations in the alpha (α; ~8-13 Hz) band, drawing clear parallels with observations made in vivo. Last, we consider the relevance of these thalamic ISOs to the pathological activity that occurs in certain types of epilepsy.
Collapse
Affiliation(s)
- Stuart W Hughes
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK.
| | | | | | | |
Collapse
|
24
|
Abstract
Sleep and sleep intensity are enhanced by adenosine and its receptor agonists, whereas adenosine receptor antagonists induce wakefulness. Adenosine kinase (ADK) is the primary enzyme metabolizing adenosine in adult brain. To investigate whether adenosine metabolism or clearance affects sleep, we recorded sleep in mice with engineered mutations in Adk. Adk-tg mice overexpress a transgene encoding the cytoplasmic isoform of ADK in the brain but lack the nuclear isoform of the enzyme. Wild-type mice and Adk(+/-) mice that have a 50% reduction of the cytoplasmic and the nuclear isoforms of ADK served as controls. Adk-tg mice showed a remarkable reduction of EEG power in low frequencies in all vigilance states and in theta activity (6.25-11 Hz) in rapid eye movement (REM) sleep and waking. Adk-tg mice were awake 58 min more per day than wild-type mice and spent significantly less time in REM sleep (102 ± 3 vs 128 ± 3 min in wild type). After sleep deprivation, slow-wave activity (0.75-4 Hz), the intensity component of non-rapid eye movement sleep, increased significantly less in Adk-tg mice and their slow-wave energy was reduced. In contrast, the vigilance states and EEG spectra of Adk(+/-) and wild-type mice did not differ. Our data suggest that overexpression of the cytoplasmic isoform of ADK is sufficient to alter sleep physiology. ADK might orchestrate neurotransmitter pathways involved in the generation of EEG oscillations and regulation of sleep.
Collapse
|
25
|
Greene RW, Frank MG. Slow wave activity during sleep: functional and therapeutic implications. Neuroscientist 2010; 16:618-33. [PMID: 20921564 DOI: 10.1177/1073858410377064] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Electroencephalographic slow-wave activity (EEG SWA) is an electrophysiological signature of slow (0.5 to 4.0 Hz), synchronized, oscillatory neocortical activity. In healthy individuals, EEG SWA is maximally expressed during non-rapid-eye-movement (non-REM) sleep, and intensifies as a function of prior wake duration. Many of the cellular and network mechanisms generating EEG SWA have been identified, but a number of questions remain unanswered. For example, although EEG SWA is a marker of sleep need, its precise relationship with sleep homeostasis and its roles in the brain are unknown. In this review, the authors discuss their current understanding of the neural mechanisms and possible functions of EEG SWA.
Collapse
Affiliation(s)
- Robert W Greene
- Department of Psychiatry, UTSW Medical Center, Dallas VA, Dallas, Texas 75390, USA.
| | | |
Collapse
|
26
|
Bjorness TE, Greene RW. Adenosine and sleep. Curr Neuropharmacol 2010; 7:238-45. [PMID: 20190965 PMCID: PMC2769007 DOI: 10.2174/157015909789152182] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/04/2009] [Accepted: 05/05/2009] [Indexed: 11/22/2022] Open
Abstract
Over the last several decades the idea that adenosine (Ado) plays a role in sleep control was postulated due in large part to pharmacological studies that showed the ability of Ado agonists to induce sleep and Ado antagonists to decrease sleep. A second wave of research involving in vitro cellular analytic approaches and subsequently, the use of neurochemical tools such as microdialysis, identified a population of cells within the brainstem and basal forebrain arousal centers, with activity that is both tightly coupled to thalamocortical activation and under tonic inhibitory control by Ado. Most recently, genetic tools have been used to show that Ado receptors regulate a key aspect of sleep, the slow wave activity expressed during slow wave sleep. This review will briefly introduce some of the phenomenology of sleep and then summarize the effect of Ado levels on sleep, the effect of sleep on Ado levels, and recent experiments using mutant mouse models to characterize the role for Ado in sleep control and end with a discussion of which Ado receptors are involved in such control. When taken together, these various experiments suggest that while Ado does play a role in sleep control, it is a specific role with specific functional implications and it is one of many neurotransmitters and neuromodulators affecting the complex behavior of sleep. Finally, since the majority of adenosine-related experiments in the sleep field have focused on SWS, this review will focus largely on SWS; however, the role of adenosine in REM sleep behavior will be addressed.
Collapse
|
27
|
Biel M, Wahl-Schott C, Michalakis S, Zong X. Hyperpolarization-activated cation channels: from genes to function. Physiol Rev 2009; 89:847-85. [PMID: 19584315 DOI: 10.1152/physrev.00029.2008] [Citation(s) in RCA: 726] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a small subfamily of proteins within the superfamily of pore-loop cation channels. In mammals, the HCN channel family comprises four members (HCN1-4) that are expressed in heart and nervous system. The current produced by HCN channels has been known as I(h) (or I(f) or I(q)). I(h) has also been designated as pacemaker current, because it plays a key role in controlling rhythmic activity of cardiac pacemaker cells and spontaneously firing neurons. Extensive studies over the last decade have provided convincing evidence that I(h) is also involved in a number of basic physiological processes that are not directly associated with rhythmicity. Examples for these non-pacemaking functions of I(h) are the determination of the resting membrane potential, dendritic integration, synaptic transmission, and learning. In this review we summarize recent insights into the structure, function, and cellular regulation of HCN channels. We also discuss in detail the different aspects of HCN channel physiology in the heart and nervous system. To this end, evidence on the role of individual HCN channel types arising from the analysis of HCN knockout mouse models is discussed. Finally, we provide an overview of the impact of HCN channels on the pathogenesis of several diseases and discuss recent attempts to establish HCN channels as drug targets.
Collapse
Affiliation(s)
- Martin Biel
- Center for Integrated Protein Science CIPS-M and Zentrum für Pharmaforschung, Department Pharmazie, Pharmakologie für Naturwissenschaften, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich D-81377, Germany.
| | | | | | | |
Collapse
|
28
|
Abstract
During sleep, the mammalian CNS undergoes widespread, synchronized slow-wave activity (SWA) that directly varies with previous waking duration (Borbély, 1982; Dijk et al., 1990). When sleep is restricted, an enhanced SWA response follows in the next sleep period. The enhancement of SWA is associated with improved cognitive performance (Huber et al., 2004), but it is unclear either how the SWA is enhanced or whether SWA is needed to maintain normal cognitive performance. A conditional, CNS knock-out of the adenosine receptor, AdoA(1)R gene, shows selective attenuation of the SWA rebound response to restricted sleep, but sleep duration is not affected. During sleep restriction, wild phenotype animals express a rebound SWA response and maintain cognitive performance in a working memory task. However, the knock-out animals not only show a reduced rebound SWA response but they also fail to maintain normal cognitive function, although this function is normal when sleep is not restricted. Thus, AdoA(1)R activation is needed for normal rebound SWA, and when the SWA rebound is reduced, there is a failure to maintain working memory function, suggesting a functional role for SWA homeostasis.
Collapse
|
29
|
Lőrincz ML, Geall F, Bao Y, Crunelli V, Hughes SW. ATP-dependent infra-slow (<0.1 Hz) oscillations in thalamic networks. PLoS One 2009; 4:e4447. [PMID: 19212445 PMCID: PMC2637539 DOI: 10.1371/journal.pone.0004447] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 12/08/2008] [Indexed: 11/19/2022] Open
Abstract
An increasing number of EEG and resting state fMRI studies in both humans and animals indicate that spontaneous low frequency fluctuations in cerebral activity at <0.1 Hz (infra-slow oscillations, ISOs) represent a fundamental component of brain functioning, being known to correlate with faster neuronal ensemble oscillations, regulate behavioural performance and influence seizure susceptibility. Although these oscillations have been commonly indicated to involve the thalamus their basic cellular mechanisms remain poorly understood. Here we show that various nuclei in the dorsal thalamus in vitro can express a robust ISO at ∼0.005–0.1 Hz that is greatly facilitated by activating metabotropic glutamate receptors (mGluRs) and/or Ach receptors (AchRs). This ISO is a neuronal population phenomenon which modulates faster gap junction (GJ)-dependent network oscillations, and can underlie epileptic activity when AchRs or mGluRs are stimulated excessively. In individual thalamocortical neurons the ISO is primarily shaped by rhythmic, long-lasting hyperpolarizing potentials which reflect the activation of A1 receptors, by ATP-derived adenosine, and subsequent opening of Ba2+-sensitive K+ channels. We argue that this ISO has a likely non-neuronal origin and may contribute to shaping ISOs in the intact brain.
Collapse
Affiliation(s)
- Magor L. Lőrincz
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Freya Geall
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Ying Bao
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Stuart W. Hughes
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
- * E-mail:
| |
Collapse
|
30
|
Reciprocal modulation of I h and I TASK in thalamocortical relay neurons by halothane. Pflugers Arch 2008; 456:1061-73. [DOI: 10.1007/s00424-008-0482-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 02/12/2008] [Accepted: 02/21/2008] [Indexed: 11/26/2022]
|
31
|
Deng P, Zhang Y, Xu ZC. Inhibition of Ih in striatal cholinergic interneurons early after transient forebrain ischemia. J Cereb Blood Flow Metab 2008; 28:939-47. [PMID: 18000510 DOI: 10.1038/sj.jcbfm.9600583] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Striatal cholinergic interneurons are relatively resistant to ischemic insults. These neurons express hyperpolarization-activated cation current (I(h)) that profoundly regulates neuronal excitability. Changes in neuronal excitability early after ischemia may be crucial for determining neuronal injury. Here we report that I(h) in cholinergic interneurons was decreased 3 h after transient forebrain ischemia, which was accompanied by a negative shift of the voltage dependence of activation. The inhibition of I(h) might be due to the tonic activation of adenosine A1 receptors, as blockade of A1 receptors significantly increased I(h) in postischemic neurons, but had no effect on control neurons. Consistent with the inhibition of I(h), postischemic neurons showed a reduction in both spontaneous firing and hyperpolarization-induced rebound depolarization. These findings indicate that I(h) may play excitatory roles in striatal cholinergic interneurons. Postischemic inhibition of I(h) might be a novel mechanism by which adenosine confers neuronal resistance to cerebral ischemia.
Collapse
Affiliation(s)
- Ping Deng
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | | | | |
Collapse
|
32
|
Clasadonte J, Poulain P, Beauvillain JC, Prevot V. Activation of neuronal nitric oxide release inhibits spontaneous firing in adult gonadotropin-releasing hormone neurons: a possible local synchronizing signal. Endocrinology 2008; 149:587-96. [PMID: 18006627 DOI: 10.1210/en.2007-1260] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The activation of nitric oxide (NO) signaling pathways in hypothalamic neurons plays a key role in the control of GnRH secretion that is central to reproductive function. It is unknown whether NO directly modulates the firing behavior of GnRH neurons in the preoptic region of the mature brain. Using patch-clamp recordings from GnRH neurons expressing green fluorescent protein in adult mice brain slices, we demonstrate that the NO precursor, L-arginine (Arg), or the NO donor, diethylamine/NO, induced a robust and reversible reduction in the spontaneous firing activity of GnRH neurons, including bursting activity. The effects of L-Arg were prevented by the NO synthase inhibitor N omega-nitro-L-Arg methyl ester hydrochloride. Histochemical studies revealing a close anatomical relationship between neurons producing NO and GnRH perikarya, together with the loss of the L-Arg-mediated inhibition of GnRH neuronal activity via the selective blockade of neuronal NO synthase, suggested that the primary source of local NO production in the mouse preoptic region was neuronal. Synaptic transmission uncoupling did not alter the effect of NO, suggesting that NO affects the firing pattern of GnRH neurons by acting at a postsynaptic site. We also show that the NO-mediated changes in membrane properties in the GnRH neurons require soluble guanylyl cyclase activity and may involve potassium conductance. By revealing that NO is a direct modulator of GnRH neuronal activity, our results introduce the intriguing possibility that this gaseous neurotransmitter may be used by the sexual brain to modulate burst firing patterns. It may set into phase the bursting activity of GnRH neurons at key stages of reproductive physiology.
Collapse
Affiliation(s)
- Jérôme Clasadonte
- Inserm, Jean-Pierre Aubert Research Center, Unité 837, Development and Plasticity of the Postnatal Brain, Place de Verdun, 59045, Lille Cedex, France
| | | | | | | |
Collapse
|
33
|
Carr DB, Andrews GD, Glen WB, Lavin A. alpha2-Noradrenergic receptors activation enhances excitability and synaptic integration in rat prefrontal cortex pyramidal neurons via inhibition of HCN currents. J Physiol 2007; 584:437-50. [PMID: 17702809 PMCID: PMC2277172 DOI: 10.1113/jphysiol.2007.141671] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 08/10/2007] [Indexed: 11/08/2022] Open
Abstract
Stimulation of alpha(2)-noradrenergic (NA) receptors within the PFC improves working memory performance. This improvement is accompanied by a selective increase in the activity of PFC neurons during delay periods, although the cellular mechanisms responsible for this enhanced response are largely unknown. Here we used current and voltage clamp recordings to characterize the response of layer V-VI PFC pyramidal neurons to alpha(2)-NA receptor stimulation. alpha(2)-NA receptor activation produced a small hyperpolarization of the resting membrane potential, which was accompanied by an increase in input resistance and evoked firing. Voltage clamp analysis demonstrated that alpha(2)-NA receptor stimulation inhibited a caesium and ZD7288-sensitive hyperpolarization-activated (HCN) inward current. Suppression of HCN current by alpha(2)-NA stimulation was not dependent on adenylate cyclase but instead required activation of a PLC-PKC linked signalling pathway. Similar to direct blockade of HCN channels, alpha(2)-NA receptor stimulation produced a significant enhancement in temporal summation during trains of distally evoked EPSPs. These dual effects of alpha(2)-NA receptor stimulation - membrane hyperpolarization and enhanced temporal integration - together produce an increase in the overall gain of the response of PFC pyramidal neurons to excitatory synaptic input. The net effect is the suppression of isolated excitatory inputs while enhancing the response to a coherent burst of synaptic activity.
Collapse
Affiliation(s)
- David B Carr
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Suite 403 BSB, Charleston, SC 29425, USA
| | | | | | | |
Collapse
|
34
|
Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
| |
Collapse
|
35
|
Arrigoni E, Rosenberg PA. Nitric oxide-induced adenosine inhibition of hippocampal synaptic transmission depends on adenosine kinase inhibition and is cyclic GMP independent. Eur J Neurosci 2007; 24:2471-80. [PMID: 17100836 DOI: 10.1111/j.1460-9568.2006.05124.x] [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] [Indexed: 01/13/2023]
Abstract
Adenosine is an important inhibitory neuromodulator that regulates neuronal excitability. Several studies have shown that nitric oxide induces release of adenosine. Here we investigated the mechanism of this release. We studied the effects of nitric oxide on evoked field excitatory postsynaptic potentials (fEPSPs) recorded in the CA1 area of rat hippocampal slices. The nitric oxide donor 1,1-diethyl-2-hydroxy-2-nitroso-hydrazine sodium (DEA/NO; 100 microm) depressed the fEPSP by 77.6 +/- 4.1%. This effect was abolished by the adenosine A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 400 nm), indicating that the nitric oxide effect was mediated by adenosine accumulation. The DEA/NO effect was unaltered by the 5'-ectonucleotidase inhibitor alpha,beta-methylene-adenosine 5'-diphosphate (AMP-CP; 100 microm), indicating that extracellular adenosine did not derive from ATP or cAMP release. The guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazole[4,3-a]quinoxaline-1-one (ODQ; 5 microm) did not affect nitric oxide depression of the fEPSPs, indicating that nitric oxide-mediated adenosine release was not mediated through a cGMP signaling cascade. This conclusion was confirmed by the observation that 8-(4-chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP; 1 mm) reversibly depressed the fEPSP by 24.9 +/- 4.5%, but this effect was not blocked by adenosine antagonists. Adenosine kinase inhibitor 5-iodotubercidin (ITU; 7 microm) occluded the nitric oxide effects by 74%, suggesting that inhibition of adenosine kinase activity contributes to adenosine release. In conclusion, exogenous nitric oxide evokes adenosine release by a cGMP-independent pathway. Intracellular cGMP elevation partially inhibits the fEPSP but not through adenosine release. Although a direct block of adenosine kinase by nitric oxide can not be excluded, the depression of adenosine kinase activity may be due to inhibition by its own substrate adenosine.
Collapse
Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | | |
Collapse
|
36
|
Liu ZW, Gao XB. Adenosine inhibits activity of hypocretin/orexin neurons by the A1 receptor in the lateral hypothalamus: a possible sleep-promoting effect. J Neurophysiol 2006; 97:837-48. [PMID: 17093123 PMCID: PMC1783688 DOI: 10.1152/jn.00873.2006] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons in the lateral hypothalamus (LH) that contain hypocretin/orexin have been established as important promoters of arousal. Deficiencies in the hypocretin/orexin system lead to narcolepsy. The inhibition of hypocretin/orexin neurons by sleep-promoting neurotransmitters has been suggested as one part of the sleep regulation machinery. Adenosine has been identified as a sleep promoter and its role in sleep regulation in the basal forebrain has been well documented. However, the effect of adenosine on arousal-promoting hypocretin/orexin neurons has not been addressed, despite recent evidence that immunocytochemical visualization of adenosine receptors was detected in these neurons. In this study, we examined the hypothesis that adenosine inhibits the activity of hypocretin/orexin neurons by using electrophysiological methods in brain slices from mice expressing green fluorescent protein in hypocretin/orexin neurons. We found that adenosine significantly attenuated the frequency of action potentials without a change in membrane potential in hypocretin/orexin neurons. The adenosine-mediated inhibition arises from depression of excitatory synaptic transmission to hypocretin/orexin neurons because adenosine depresses the amplitude of evoked excitatory postsynaptic potential and the frequency of spontaneous and miniature excitatory postsynaptic currents in these neurons. At the cell body of the hypocretin/orexin neurons, adenosine inhibits voltage-dependent calcium currents without the induction of GIRK current. The inhibitory effect of adenosine is dose dependent, pertussis toxin sensitive, and mediated by A1 receptors. In summary, our data suggest that in addition to its effect in the basal forebrain, adenosine exerts its sleep-promoting effect in the LH by inhibition of hypocretin/orexin neurons.
Collapse
Affiliation(s)
- Zhong-Wu Liu
- Department of OB/GYN and Reproductive Science, Yale University School of Medicine, New Haven, CT 06520
- Department of Neurobiology, Yunyang Medical College, Shiyan, Hubei 442000, P. R. China
| | - Xiao-Bing Gao
- Department of OB/GYN and Reproductive Science, Yale University School of Medicine, New Haven, CT 06520
| |
Collapse
|
37
|
Liersch J, Räder C, Görcs T, Scholten A, Kremmer E, Plüm J, Pöggel S, Zilles K. WITHDRAWN: Immunohistochemical localization of Ih channel HCN3 in the rat brain. ANATOMY AND EMBRYOLOGY 2006. [PMID: 16897011 DOI: 10.1007/s00429-006-0108-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/26/2006] [Indexed: 05/11/2023]
Abstract
Ahead of Print article withdrawn by publisher
Collapse
Affiliation(s)
- J Liersch
- Institute of Brain Research C. and O. Vogt, Heinrich Heine University, Düsseldorf, Germany
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Budde T, Caputi L, Kanyshkova T, Staak R, Abrahamczik C, Munsch T, Pape HC. Impaired regulation of thalamic pacemaker channels through an imbalance of subunit expression in absence epilepsy. J Neurosci 2006; 25:9871-82. [PMID: 16251434 PMCID: PMC6725576 DOI: 10.1523/jneurosci.2590-05.2005] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The role of hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channel isoforms and hyperpolarization-activated cation current (Ih) for seizure-related burst firing in thalamocortical (TC) neurons was investigated in a rat genetic model of absence epilepsy [Wistar Albino Glaxo rats, bred in Rijswijk (WAG/Rij)]. Burst discharges in TC neurons locked to seizure activity in vivo were prolonged during blockade of Ih by Cs+ and ZD7288 (4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidinium chloride). In vitro analyses revealed a hyperpolarizing shift of half-maximal Ih activation (Vh) in WAG/Rij (Vh = -93.2 mV) compared with nonepileptic controls [August x Copenhagen-Irish (ACI) (Vh = -88.0 mV)]. This effect is explained by a shift of the responsiveness of Ih to cAMP toward higher concentrations in TC neurons from WAG/Rij, as revealed by application of 8-bromo-cAMP and the phosphodiesterase inhibitor IBMX. During blockade of adenylyl cyclase activity, Ih activation was similar in the two strains, whereas the difference in cAMP responsiveness persisted, thereby voting against different ambient cAMP levels between strains. Increasing the intracellular cAMP level and shifting Ih activation led to a change from burst to tonic firing mode in WAG/Rij but not in ACI rats. Furthermore, HCN1 expression was significantly increased on mRNA and protein levels, with no changes in HCN2-4 expression. In conclusion, there is an increase in HCN1 expression in the epileptic thalamus, associated with a decrease in cAMP responsiveness of Ih in TC neurons and resulting impairment to control the shift from burst to tonic firing, which, in turn, will prolong burst activity after recruitment of Ih during absence seizures.
Collapse
MESH Headings
- 1-Methyl-3-isobutylxanthine/pharmacology
- 8-Bromo Cyclic Adenosine Monophosphate/pharmacology
- Action Potentials/drug effects
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Animals
- Blotting, Northern/methods
- Cerebral Cortex/cytology
- Cesium/pharmacology
- Chlorides/pharmacology
- Cyclic Nucleotide-Gated Cation Channels
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Dose-Response Relationship, Radiation
- Drug Interactions
- Electric Stimulation/methods
- Electroencephalography/methods
- Enzyme Inhibitors/pharmacology
- Epilepsy, Absence/genetics
- Epilepsy, Absence/metabolism
- Epilepsy, Absence/physiopathology
- Female
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels
- Immunohistochemistry/methods
- In Situ Hybridization/methods
- In Vitro Techniques
- Ion Channels/metabolism
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Membrane Potentials/radiation effects
- Microinjections
- Neurons/metabolism
- Patch-Clamp Techniques/methods
- Potassium Channels
- Protein Isoforms/metabolism
- Pyrimidines/pharmacology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Mutant Strains
- Rats, Wistar
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Thalamus/cytology
Collapse
Affiliation(s)
- Thomas Budde
- Institut für Experimentelle Epilepsieforschung, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | | | | | | | | | | | | |
Collapse
|
39
|
Arrigoni E, Chamberlin NL, Saper CB, McCarley RW. Adenosine inhibits basal forebrain cholinergic and noncholinergic neurons in vitro. Neuroscience 2006; 140:403-13. [PMID: 16542780 DOI: 10.1016/j.neuroscience.2006.02.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Revised: 01/23/2006] [Accepted: 02/04/2006] [Indexed: 11/20/2022]
Abstract
Adenosine has been proposed as a homeostatic "sleep factor" that promotes the transition from waking to sleep by affecting several sleep-wake regulatory systems. In the basal forebrain, adenosine accumulates during wakefulness and, when locally applied, suppresses neuronal activity and promotes sleep. However, the neuronal phenotype mediating these effects is unknown. We used whole-cell patch-clamp recordings in in vitro rat brain slices to investigate the effect of adenosine on identified cholinergic and noncholinergic neurons of the magnocellular preoptic nucleus and substantia innominata. Adenosine (0.5-100 microM) reduced the magnocellular preoptic nucleus and substantia innominata cholinergic neuronal firing rate by activating an inwardly rectifying potassium current that reversed at -82 mV and was blocked by barium (100 microM). Application of the A1 receptor antagonist 8-cyclo-pentyl-theophylline (200 nM) blocked the effects of adenosine. Adenosine was also tested on two groups of electrophysiologically distinct noncholinergic magnocellular preoptic nucleus and substantia innominata neurons. In the first group adenosine, via activation of postsynaptic A1 receptors, reduced spontaneous firing via inhibition of the hyperpolarization-activated cation current. Blocking the H-current with ZD7288 (20 microM) abolished adenosine effects on these neurons. The second group was not affected by adenosine. These results demonstrate that, in the magnocellular preoptic nucleus and substantia innominata region of the basal forebrain, adenosine inhibits both cholinergic neurons and a subset of noncholinergic neurons. Both of these effects occur via postsynaptic A1 receptors, but are mediated downstream by two separate mechanisms.
Collapse
Affiliation(s)
- E Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Room 814, 77 Louis Pasteur Avenue, Boston, MA 02115, USA.
| | | | | | | |
Collapse
|
40
|
Brambilla D, Chapman D, Greene R. Adenosine mediation of presynaptic feedback inhibition of glutamate release. Neuron 2005; 46:275-83. [PMID: 15848805 DOI: 10.1016/j.neuron.2005.03.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 01/11/2005] [Accepted: 03/12/2005] [Indexed: 11/23/2022]
Abstract
Conditions of increased metabolic demand relative to metabolite availability are associated with increased extracellular adenosine in CNS tissue. Synaptic activation of postsynaptic NMDA receptors on neurons of the cholinergic brainstem arousal center can increase sufficient extracellular adenosine to act on presynaptic A1 adenosine receptors (A1ADRs) of glutamate terminals, reducing release from the readily releasable pool. The time course of the adenosine response to an increase in glutamate release is slow (tau > 10 min), consistent with the role of adenosine as a fatigue factor that inhibits the activity of cholinergic arousal centers to reduce arousal.
Collapse
Affiliation(s)
- Dario Brambilla
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | | | | |
Collapse
|
41
|
Frère SGA, Kuisle M, Lüthi A. Regulation of recombinant and native hyperpolarization-activated cation channels. Mol Neurobiol 2005; 30:279-305. [PMID: 15655253 DOI: 10.1385/mn:30:3:279] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Accepted: 03/22/2004] [Indexed: 11/11/2022]
Abstract
Ionic currents generated by hyperpolarization-activated cation-nonselective (HCN) channels have been principally known as pacemaker h-currents (Ih), because they allow cardiac and neuronal cells to be rhythmically active over precise intervals of time. Presently, these currents are implicated in numerous additional cellular functions, including neuronal integration, synaptic transmission, and sensory reception. These roles are accomplished by virtue of the regulation of Ih by both voltage and ligands. The article summarizes recent developments on the properties and allosteric interactions of these two regulatory pathways in cloned and native channels. Additionally, it discusses how the expression and properties of native channels may be controlled via regulation of the transcription of the HCN channel gene family and the assembly of channel subunits. Recently, several cardiac and neurological diseases were found to be intimately associated with a dysregulation of HCN gene transcription, suggesting that HCN-mediated currents may be involved in the pathophysiology of excitable systems. As a starting point, we briefly review the general characteristics of Ih and the regulatory mechanisms identified in heterologously expressed HCN channels.
Collapse
Affiliation(s)
- Samuel G A Frère
- Section of Pharmacology and Neurobiology, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | | | | |
Collapse
|
42
|
Lu Y, Li Y, Herin GA, Aizenman E, Epstein PM, Rosenberg PA. Elevation of intracellular cAMP evokes activity-dependent release of adenosine in cultured rat forebrain neurons. Eur J Neurosci 2004; 19:2669-81. [PMID: 15147301 DOI: 10.1111/j.0953-816x.2004.03396.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Adenosine is an important regulator of neuronal excitability. Zaprinast is a cyclic nucleotide phosphodiesterase inhibitor, and has been shown in the hippocampal slice to suppress excitation. This action can be blocked by an adenosine receptor antagonist, and therefore is presumably due to adenosine release stimulated by exposure to zaprinast. To explore the mechanism of this phenomenon further, we examined the effect of zaprinast on adenosine release itself in cultured rat forebrain neurons. Zaprinast significantly stimulated extracellular adenosine accumulation. The effect of zaprinast on adenosine appeared to be mediated by increasing intracellular cyclic adenosine monophosphate (cAMP) and activation of protein kinase A (PKA): (i) zaprinast stimulated intracellular cAMP accumulation; (ii) a cAMP antagonist (Rp-8-Br-cAMP) significantly reduced the zaprinast effect on adenosine; (iii) an inhibitor of phosphodiesterase (PDE)1 (vinpocetine) and an activator of adenylate cyclase (forskolin) mimicked the effect of zaprinast on adenosine. We also found that zaprinast had no effect on adenosine in astrocyte cultures, and tetrodotoxin completely blocked zaprinast-evoked adenosine accumulation in neuronal cultures, suggesting that neuronal activity was likely to be involved. Consistent with a dependence on neuronal activity, NMDA receptor antagonists (MK-801 and D-APV) and removal of extracellular glutamate by glutamate-pyruvate transaminase blocked the effect of zaprinast. In addition, zaprinast was shown to stimulate glutamate release. Thus, our data suggest that zaprinast-evoked adenosine accumulation is likely to be mediated by stimulation of glutamate release by a cAMP- and PKA-dependent mechanism, most likely by inhibition of PDE1 in neurons. Furthermore, regulation of cAMP, either by inhibiting cAMP-PDE activity or by stimulating adenylate cyclase activity, may play an important role in modulating neuronal excitability. These data suggest the existence of a homeostatic negative feedback loop in which increases in neuronal activity are damped by release of adenosine following activation of glutamate receptors.
Collapse
Affiliation(s)
- Yin Lu
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | |
Collapse
|
43
|
Frère SGA, Lüthi A. Pacemaker channels in mouse thalamocortical neurones are regulated by distinct pathways of cAMP synthesis. J Physiol 2004; 554:111-25. [PMID: 14678496 PMCID: PMC1664735 DOI: 10.1113/jphysiol.2003.050989] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A crucial aspect of pacemaker current (Ih) function is the regulation by cyclic nucleotides. To assess the endogenous mechanisms controlling cAMP levels in the vicinity of pacemaker channels, Ih regulation by G-protein-coupled neurotransmitter receptors was studied in mouse thalamocortical neurones. Activation of beta-adrenergic receptors with (-)-isoproterenol (Iso) led to a small steady enhancement of Ih amplitude, whereas activation of GABAB receptors with (+/-)-Baclofen (Bac) reduced Ih, consistent with an up- and down-regulation of basal cAMP levels, respectively. In contrast, a transient (taudecay, approximately 200 s), supralinear up-regulation of Ih was observed upon coapplication of Iso and Bac that was larger than that observed with Iso alone. This up-regulation appeared to involve a cAMP synthesis pathway distinct from that recruited by Iso, as it was associated with a reversible acceleration in Ih activation kinetics and an occlusion of modulation by photolytically released cAMP, yet showed an 11 mV as opposed to a 6 mV positive shift in the activation curve and an at least seven-fold increase in duration. GABA, in the presence of the GABAA antagonist picrotoxin, mimicked, whereas N-ethylmaleimide, an inhibitor of Gi-proteins, blocked the up-regulation, supporting a requirement for GABAB receptor activation in the potentiation. Activation of synaptic GABAB responses via stimulation of inhibitory afferents from the nucleus reticularis potentiated Iso-induced increments in Ih, suggesting that synaptically located receptors couple positively to cAMP synthesis induced by beta-adrenergic receptors. These findings indicate that distinct pathways of cAMP synthesis target the pacemaker current and the recruitment of these may be controlled by GABAergic activity within thalamic networks.
Collapse
Affiliation(s)
- Samuel G A Frère
- Section of Pharmacology and Neurobiology, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
| | | |
Collapse
|
44
|
Greene R, Siegel J. Sleep: a functional enigma. Neuromolecular Med 2004; 5:59-68. [PMID: 15001813 PMCID: PMC8802886 DOI: 10.1385/nmm:5:1:059] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2003] [Accepted: 12/01/2003] [Indexed: 11/11/2022]
Abstract
Although continued total sleep deprivation is fatal, the function of sleep remains a mystery. Shorter durations of sleep deprivation are followed by rebound increases in non-rapid eye movement (non-REM) sleep, suggesting a homeostatic control. Measurements of the power spectrum of the electroencephalograph (EEG) suggest that a more accurate marker of the homeostasis may be delta frequency power, because it most closely reflects the duration of the preceding sleep deprivation. Several lines of evidence suggest a link with complex metabolic processes. These include a local homeostatic factor, adenosine, that inhibits neuronal activity in response to increases in the ratio of energy demand to metabolite availability. Other evidence derives from the relationship of circadian genes, NPAS2 and Clock, to metabolism. Additionally, at a systems level, hypocretin/Orexin may coordinate motor activity with feeding. A loss of hypocretin neurons or a mutation of the genes controlling this peptide system can result in the sleep disorder narcolepsy. Finally, evidence for a role of non-REM sleep in developmental central nervous system (CNS) plasticity, as well as learning and memory, is discussed.
Collapse
Affiliation(s)
- Robert Greene
- Department of Psychiatry, VAMC Dallas & UTSW, Dallas, TX, USA.
| | | |
Collapse
|
45
|
Liu Z, Bunney EB, Appel SB, Brodie MS. Serotonin reduces the hyperpolarization-activated current (Ih) in ventral tegmental area dopamine neurons: involvement of 5-HT2 receptors and protein kinase C. J Neurophysiol 2003; 90:3201-12. [PMID: 12890794 DOI: 10.1152/jn.00281.2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dopaminergic neurons of the ventral tegmental area (VTA) have been implicated in the rewarding properties of drugs of abuse and in the etiology of schizophrenia; serotonin modulation of these neurons may play a role in these phenomena. Whole cell patch-in-the-slice recording in rat brain slices was used to investigate modulation of the hyperpolarization-activated cationic current Ih by serotonin in these neurons. Serotonin (50-500 microM) reduced the amplitude of Ih in a concentration-dependent manner; this effect was reversible after prolonged washout of serotonin. This effect was mimicked by the 5-HT2 agonist alpha-methylserotonin (25 microM) and reversed by the 5-HT2 antagonist ketanserin (25 microM). Serotonin reduced the maximal Ih current and conductance (measured at -130 mV) and caused a negative shift in the voltage dependence of Ih activation. The serotonin-induced reduction in Ih amplitude was antagonized by intracellular administration of the nonspecific protein kinase inhibitor H-7 (75 microM) and the selective protein kinase C inhibitor chelerythrine (25 microM). The protein kinase C activator phorbol 12, 13 diacetate (PDA, 2 microM) reduced Ih amplitude; when PDA and serotonin were applied together, the effect on Ih was less than additive. These data support the conclusion that serotonin reduces Ih in dopaminergic VTA neurons by acting at serotonin 5-HT2 receptors, which activate protein kinase C. This reduction of Ih may be physiologically important, as the selective inhibitor of Ih, ZD7288, significantly increased dopamine inhibition of firing rate of dopaminergic VTA neurons, an effect that we previously demonstrated with serotonin.
Collapse
Affiliation(s)
- Zhaoping Liu
- Departments of Physiology and Biophysics and Emergency Medicine, University of Illinois, Chicago, Illinois 60612, USA
| | | | | | | |
Collapse
|
46
|
Funahashi M, Mitoh Y, Kohjitani A, Matsuo R. Role of the hyperpolarization-activated cation current (Ih) in pacemaker activity in area postrema neurons of rat brain slices. J Physiol 2003; 552:135-48. [PMID: 12897173 PMCID: PMC2343317 DOI: 10.1113/jphysiol.2003.047191] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
To clarify the functional properties of the hyperpolarization-activated cation current (Ih) as a pacemaker current in area postrema neurons, whole-cell recordings were made in visually identified cells in rat brain slices. The activation of Ih was identified in approximately 62 % of area postrema neurons tested. The cells displaying Ih showed a depolarizing "sag" in responses to hyperpolarizing current injection in current-clamp mode. The reversal potential for the Ih was -36 mV, and this was shown to depend on the external concentration of Na+ and K+ ions. Extracellular Cs+ ions (2 mM) and ZD7288 (100 microM), a potent selective Ih channel antagonist, blocked Ih and induced a membrane potential hyperpolarization, suggesting the sustained activation of Ih near the resting potential and a contribution from Ih to membrane potential maintenance at more depolarized levels. In contrast, extracellular Ba2+ ions caused a depolarization of the membrane potential, suggesting the blockade of inward rectifier K+ currents. ZD7288 decreased the spontaneous discharge rate by prolonging the slow depolarization between two spikes, with minimal effect on the amplitude of the afterhyperpolarization or action potential waveforms. Ih stabilized the latency of rebound action potentials. Ih was weakly activated by external 8-bromoadenosine 3',5' cyclic monophosphate (1 mM) or forskolin (50-100 microM), indicating that the Ih channel subtypes in area postrema cells could be modulated by intracellular cAMP. Our findings indicate that Ih contributes to the subthreshold membrane and firing properties of rat area postrema neurons and may regulate their resting membrane potential and firing patterns.
Collapse
Affiliation(s)
- Makoto Funahashi
- Department of Oral Physiology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
| | | | | | | |
Collapse
|
47
|
Pan ZZ. Kappa-opioid receptor-mediated enhancement of the hyperpolarization-activated current (I(h)) through mobilization of intracellular calcium in rat nucleus raphe magnus. J Physiol 2003; 548:765-75. [PMID: 12651920 PMCID: PMC2342905 DOI: 10.1113/jphysiol.2002.037622] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The hyperpolarization-activated current (Ih) is important in the control of resting membrane potential, in the regulation of network firing pattern and in the modulation of presynaptic transmitter release in central neurons. Recent studies on native and cloned Ih channels have demonstrated that the Ih channel is commonly modulated by cAMP through a positive shift in its voltage dependence without a change in its maximum current. The present study demonstrates that activation of kappa-opioid receptors enhances Ih by increasing its maximum current in brainstem neurons in the nucleus raphe magnus. Agents that interfere with the release of intracellular calcium from calcium stores altered the maximum Ih and significantly attenuated the kappa-receptor-mediated enhancement of Ih. These results suggest that kappa-opioid receptors enhance the maximum Ih by mobilizing intracellular calcium from calcium stores. This provides a physiological function for kappa-receptor-stimulated calcium release and may suggest another Ih-regulating mechanism by intracellular calcium in central neurons.
Collapse
Affiliation(s)
- Zhizhong Z Pan
- Department of Symptom Research, University of Texas-MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
| |
Collapse
|
48
|
|
49
|
Goaillard JM, Vincent P. Serotonin suppresses the slow afterhyperpolarization in rat intralaminar and midline thalamic neurones by activating 5-HT(7) receptors. J Physiol 2002; 541:453-65. [PMID: 12042351 PMCID: PMC2290335 DOI: 10.1113/jphysiol.2001.013896] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
While the highest expression level of 5-HT(7) receptors in the brain is observed in intralaminar and midline thalamic neurones, the physiological role of these receptors in this structure is unknown. In vivo recordings have shown that stimulation of the serotonergic raphe nuclei can alter the response of these neurones to a nociceptive stimulus, suggesting that serotonin modulates their firing properties. Using the patch-clamp technique in rat thalamic brain slices, we demonstrate that activation of 5-HT(7) receptors can strongly modulate the excitability of intralaminar and midline thalamic neurones by inhibiting the calcium-activated potassium conductance that is responsible for the slow afterhyperpolarization (sAHP) following a spike discharge. This sAHP was inhibited after activation of the cAMP pathway, either by bath application of forskolin or intracellular perfusion with 8-bromo-cAMP. The inhibitory effect of 5-HT(7) receptors on sAHPs was blocked by the protein kinase A antagonist R(P)-cAMPS. Calcium-imaging experiments showed no change in intracellular calcium levels during the 5-HT(7) response, indicating that in these neurones, a global calcium signal was not necessary to activate the cAMP cascade. Finally, bath application of serotonin produced a strong increase in cytosolic cAMP concentration, as measured using the fluorescent probe FlCRhR, and an inhibition of the sAHP. Taken together, these results suggest that 5-HT(7) receptors are implicated in the effect of 5-HT on sAHP in intralaminar and midline thalamic neurones, an effect that is mediated by the cAMP second-messenger cascade.
Collapse
Affiliation(s)
- Jean-Marc Goaillard
- Equipe Neurobiologie Cellulaire, Neurobiologie des Processus Adaptatifs UMR 7102, CNRS Université Paris VI, F-75005 Paris, France
| | | |
Collapse
|
50
|
Takigawa T, Alzheimer C. Phasic and tonic attenuation of EPSPs by inward rectifier K+ channels in rat hippocampal pyramidal cells. J Physiol 2002; 539:67-75. [PMID: 11850502 PMCID: PMC2290130 DOI: 10.1113/jphysiol.2001.012883] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We made whole-cell recordings from CA1 pyramidal cells of hippocampal slices in combination with brief dendritic glutamate pulses to study the role of constitutive inwardly rectifying K+ channels (IRK, Kir2.0) and G-protein-activated inwardly rectifying K+ channels (GIRK, Kir3.0) in the processing of excitatory inputs. Phasic activation of GIRK channels by baclofen (20 microM) produced a reversible reduction of glutamate-evoked postsynaptic potentials (GPSPs), our equivalent of EPSPs, by about one-third. Conversely, tertiapin (30 nM), a selective inhibitor of GIRK channels, and Ba2+ (200 microM), a non-selective blocker of inwardly rectifying K+ channels, enhanced GPSPs and, in voltage-clamp experiments, reduced the underlying K+ conductances, indicating a functionally significant background GIRK conductance, in addition to constitutive IRK channel activity. When examined after suppression of endogenous adenosinergic inhibition, using either adenosine deaminase or the selective A1 receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine, tertiapin failed to influence either the GPSPs or the inwardly rectifying K+ conductance. Voltage-clamp recordings from acutely isolated CA1 pyramidal cells not exposed to ambient adenosine exhibited no response to tertiapin, whereas Ba2+ was still capable of reducing hyperpolarizing inward rectification. Our data indicate that in hippocampal pyramidal cells, two components of the inwardly rectifying K+ conductance can be identified, which together exert a tonic modulation of excitatory synaptic input: one arises from constitutive putative IRK channels, the other is mediated by the background activity of GIRK channels that results from the tonic activation of A1 receptors by ambient adenosine.
Collapse
Affiliation(s)
- Tomoko Takigawa
- Department of Physiology, University of Munich, Pettenkoferstr. 12, 80336 Munich, Germany
| | | |
Collapse
|