1
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Sitnikova E, Rutskova E, Smirnov K. Alpha2-Adrenergic Receptors as a Pharmacological Target for Spike-Wave Epilepsy. Int J Mol Sci 2023; 24:1477. [PMID: 36674992 PMCID: PMC9862736 DOI: 10.3390/ijms24021477] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Spike-wave discharges are the hallmark of idiopathic generalized epilepsy. They are caused by a disorder in the thalamocortical network. Commercially available anti-epileptic drugs have pronounced side effects (i.e., sedation and gastroenterological concerns), which might result from a low selectivity to molecular targets. We suggest a specific subtype of adrenergic receptors (ARs) as a promising anti-epileptic molecular target. In rats with a predisposition to absence epilepsy, alpha2 ARs agonists provoke sedation and enhance spike-wave activity during transitions from awake/sedation. A number of studies together with our own observations bring evidence that the sedative and proepileptic effects require different alpha2 ARs subtypes activation. Here we introduce a new concept on target pharmacotherapy of absence epilepsy via alpha2B ARs which are presented almost exclusively in the thalamus. We discuss HCN and calcium channels as the most relevant cellular targets of alpha2 ARs involved in spike-wave activity generation.
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Affiliation(s)
- Evgenia Sitnikova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
| | - Elizaveta Rutskova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
| | - Kirill Smirnov
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Bld. 1, Moscow 121205, Russia
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2
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Xu X, Wu G. Human C1orf27 protein interacts with α 2A-adrenergic receptor and regulates its anterograde transport. J Biol Chem 2022; 298:102021. [PMID: 35551911 PMCID: PMC9168726 DOI: 10.1016/j.jbc.2022.102021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
The molecular mechanisms underlying the anterograde surface transport of G protein–coupled receptors (GPCRs) after their synthesis in the endoplasmic reticulum (ER) are not well defined. In C. elegans, odorant response abnormal 4 has been implicated in the delivery of olfactory GPCRs to the cilia of chemosensory neurons. However, the function and regulation of its human homolog, C1orf27, in GPCR transport or in general membrane trafficking remain unknown. Here, we demonstrate that siRNA-mediated knockdown of C1orf27 markedly impedes the ER-to-Golgi export kinetics of newly synthesized α2A-adrenergic receptor (α2A-AR), a prototypic GPCR, with the half-time being prolonged by more than 65%, in mammalian cells in retention using the selective hooks assays. Using modified bioluminescence resonance energy transfer assays and ELISAs, we also show that C1orf27 knockdown significantly inhibits the surface transport of α2A-AR. Similarly, C1orf27 knockout by CRISPR-Cas9 markedly suppresses the ER–Golgi-surface transport of α2A-AR. In addition, we demonstrate that C1orf27 depletion attenuates the export of β2-AR and dopamine D2 receptor but not of epidermal growth factor receptor. We further show that C1orf27 physically associates with α2A-AR, specifically via its third intracellular loop and C terminus. Taken together, these data demonstrate an important role of C1orf27 in the trafficking of nascent GPCRs from the ER to the cell surface through the Golgi and provide novel insights into the regulation of the biosynthesis and anterograde transport of the GPCR family members.
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Affiliation(s)
- Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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3
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Joshi S, Gold JI. Context-dependent relationships between locus coeruleus firing patterns and coordinated neural activity in the anterior cingulate cortex. eLife 2022; 11:63490. [PMID: 34994344 PMCID: PMC8765756 DOI: 10.7554/elife.63490] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/16/2021] [Indexed: 01/30/2023] Open
Abstract
Ascending neuromodulatory projections from the locus coeruleus (LC) affect cortical neural networks via the release of norepinephrine (NE). However, the exact nature of these neuromodulatory effects on neural activity patterns in vivo is not well understood. Here, we show that in awake monkeys, LC activation is associated with changes in coordinated activity patterns in the anterior cingulate cortex (ACC). These relationships, which are largely independent of changes in firing rates of individual ACC neurons, depend on the type of LC activation: ACC pairwise correlations tend to be reduced when ongoing (baseline) LC activity increases but enhanced when external events evoke transient LC responses. Both relationships covary with pupil changes that reflect LC activation and arousal. These results suggest that modulations of information processing that reflect changes in coordinated activity patterns in cortical networks can result partly from ongoing, context-dependent, arousal-related changes in activation of the LC-NE system.
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Affiliation(s)
- Siddhartha Joshi
- Department of Neuroscience, University of Pennsylvania, Philadelphia, United States
| | - Joshua I Gold
- Department of Neuroscience, University of Pennsylvania, Philadelphia, United States
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4
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Li C, Wei Z, Fan Y, Huang W, Su Y, Li H, Dong Z, Fukuda M, Khater M, Wu G. The GTPase Rab43 Controls the Anterograde ER-Golgi Trafficking and Sorting of GPCRs. Cell Rep 2017; 21:1089-1101. [PMID: 29069590 PMCID: PMC6051424 DOI: 10.1016/j.celrep.2017.10.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/21/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) constitute the largest superfamily of cell-surface signaling proteins. However, mechanisms underlying their surface targeting and sorting are poorly understood. Here, we screen the Rab family of small GTPases in the surface transport of multiple GPCRs. We find that manipulation of Rab43 function significantly alters the surface presentation and signaling of all GPCRs studied without affecting non-GPCR membrane proteins. Rab43 specifically regulates the transport of nascent GPCRs from the endoplasmic reticulum (ER) to the Golgi. More interestingly, Rab43 directly interacts with GPCRs in an activation-dependent fashion. The Rab43-binding domain identified in the receptors effectively converts non-GPCR membrane protein transport into a Rab43-dependent pathway. These data reveal a crucial role for Rab43 in anterograde ER-Golgi transport of nascent GPCRs, as well as the ER sorting of GPCR members by virtue of its ability to interact directly.
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Affiliation(s)
- Chunman Li
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yi Fan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Wei Huang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yunchao Su
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Honglin Li
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Zheng Dong
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Mitsunori Fukuda
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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5
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Jabri MA, Wannes D, Hajji N, Sakly M, Marzouki L, Sebai H. Role of laxative and antioxidant properties of Malva sylvestris leaves in constipation treatment. Biomed Pharmacother 2017; 89:29-35. [DOI: 10.1016/j.biopha.2017.02.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 01/31/2017] [Accepted: 02/07/2017] [Indexed: 11/26/2022] Open
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6
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Beiranvand A, Nasehi M, Zarrindast MR, Moghaddasi M. Involvement of medial prefrontal cortex alpha-2 adrenoceptors on memory acquisition deficit induced by arachidonylcyclopropylamide, a cannabinoid CB1 receptor agonist, in rats; possible involvement of Ca2+ channels. J Psychopharmacol 2016; 30:945-54. [PMID: 27317021 DOI: 10.1177/0269881116652585] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Functional interactions between cannabinoid and alpha-2 adrenergic systems in cognitive control in the medial prefrontal cortex (mPFC) seem possible. The present study evaluated the possible role of alpha-2 adrenoceptors of the prefrontal cortex on effect of arachidonylcyclopropylamide (ACPA), a cannabinoid CB1 receptor (CB1R) agonist, in adult male Wistar rats. The animals were bilaterally implanted with chronic cannulae in the mPFC, trained in a step-through task, and tested 24 h after training to measure step-through latency. Results indicate that pre-training microinjection of ACPA (0.05 and 0.5 μg/rat) and clonidine (alpha-2 adrenoceptor agonist; 1 and 2 μg/rat) reduce memory acquisition. Pre-training subthreshold dose of clonidine (0.5 µg/rat) restored memory-impairing effect of ACPA (0.05 and 0.5 µg/rat). On the other hand, pre-training administration of the alpha-2 adrenoceptor antagonist yohimbine in all doses used (0.5, 1, and 2 μg/rat) did not affect memory acquisition by itself, while a subthreshold dose of yohimbine (2 µg/rat) potentiated memory impairment induced by ACPA (0.005 µg/rat). Finally, a subthreshold dose of SKF96365 (a Ca(2+) channel blocker) blocked clonidine and yohimbine effect of memory responses induced by ACPA. In conclusion, these data indicate that mPFC alpha-2 adrenoceptors play an important role in ACPA-induced amnesia and Ca(2+) channels have a critical role this phenomenon.
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Affiliation(s)
| | - Mohammad Nasehi
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad-Reza Zarrindast
- Institute for Cognitive Science Studies (ICSS), Tehran, Iran Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran Medical Genomics Research Center, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Mehrnoush Moghaddasi
- Razi Herbal Medicines Research Center, Department of Physiology, Lorestan University of Medical Sciences, Khorramabad, Iran
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7
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Schellenberger Costa M, Weigenand A, Ngo HVV, Marshall L, Born J, Martinetz T, Claussen JC. A Thalamocortical Neural Mass Model of the EEG during NREM Sleep and Its Response to Auditory Stimulation. PLoS Comput Biol 2016; 12:e1005022. [PMID: 27584827 PMCID: PMC5008627 DOI: 10.1371/journal.pcbi.1005022] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/17/2016] [Indexed: 11/18/2022] Open
Abstract
Few models exist that accurately reproduce the complex rhythms of the thalamocortical system that are apparent in measured scalp EEG and at the same time, are suitable for large-scale simulations of brain activity. Here, we present a neural mass model of the thalamocortical system during natural non-REM sleep, which is able to generate fast sleep spindles (12–15 Hz), slow oscillations (<1 Hz) and K-complexes, as well as their distinct temporal relations, and response to auditory stimuli. We show that with the inclusion of detailed calcium currents, the thalamic neural mass model is able to generate different firing modes, and validate the model with EEG-data from a recent sleep study in humans, where closed-loop auditory stimulation was applied. The model output relates directly to the EEG, which makes it a useful basis to develop new stimulation protocols. Sleep plays a pivotal role for the consolidation of memory. While REM sleep had originally been the focus of research due to its similarity with wakefulness, more recent studies suggest that different sleep stages are responsible for the consolidation of different types of memory. To better understand the changes in neuronal dynamics between the different sleep stages, neural mass models are a valuable tool, as they relate directly to the large-scale dynamics measured by an EEG. Here, we present a model of the sleeping thalamocortical system. We first show that the isolated thalamic submodule is able to generate different oscillatory behavior found in vivo. Furthermore, the full thalamocortical model reproduces the EEG of sleep stages N2 and N3 and preserves the temporal relationship between cortical K-complexes/slow oscillations and thalamic sleep spindles. A comparison with event related potential data from a recent sleep study in humans demonstrates its possible application in predicting the outcome of external stimulation on EEG rhythms. Our study shows, that a neural mass model incorporating few key mechanisms is sufficient to reproduce the complex brain dynamics observed during sleep.
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Affiliation(s)
- Michael Schellenberger Costa
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- * E-mail:
| | - Arne Weigenand
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
| | - Hong-Viet V. Ngo
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Lisa Marshall
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Jan Born
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Martinetz
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
| | - Jens Christian Claussen
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Computational Systems Biology, Jacobs University Bremen, Bremen, Germany
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8
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Modeling the effect of sleep regulation on a neural mass model. J Comput Neurosci 2016; 41:15-28. [DOI: 10.1007/s10827-016-0602-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 03/09/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
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9
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Zhang M, Davis JE, Li C, Gao J, Huang W, Lambert NA, Terry AV, Wu G. GGA3 Interacts with a G Protein-Coupled Receptor and Modulates Its Cell Surface Export. Mol Cell Biol 2016; 36:1152-63. [PMID: 26811329 PMCID: PMC4800796 DOI: 10.1128/mcb.00009-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 01/20/2016] [Indexed: 12/20/2022] Open
Abstract
Molecular mechanisms governing the anterograde trafficking of nascent G protein-coupled receptors (GPCRs) are poorly understood. Here, we have studied the regulation of cell surface transport of α2-adrenergic receptors (α2-ARs) by GGA3 (Golgi-localized, γ-adaptin ear domain homology, ADP ribosylation factor-binding protein 3), a multidomain clathrin adaptor protein that sorts cargo proteins at the trans-Golgi network (TGN) to the endosome/lysosome pathway. By using an inducible system, we demonstrated that GGA3 knockdown significantly inhibited the cell surface expression of newly synthesized α2B-AR without altering overall receptor synthesis and internalization. The receptors were arrested in the TGN. Furthermore, GGA3 knockdown attenuated α2B-AR-mediated signaling, including extracellular signal-regulated kinase 1/2 (ERK1/2) activation and cyclic AMP (cAMP) inhibition. More interestingly, GGA3 physically interacted with α2B-AR, and the interaction sites were identified as the triple Arg motif in the third intracellular loop of the receptor and the acidic motif EDWE in the VHS domain of GGA3. In contrast, α2A-AR did not interact with GGA3 and its cell surface export and signaling were not affected by GGA3 knockdown. These data reveal a novel function of GGA3 in export trafficking of a GPCR that is mediated via a specific interaction with the receptor.
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Affiliation(s)
- Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Chunman Li
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Jie Gao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Wei Huang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
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10
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Salgado H, Treviño M, Atzori M. Layer- and area-specific actions of norepinephrine on cortical synaptic transmission. Brain Res 2016; 1641:163-76. [PMID: 26820639 DOI: 10.1016/j.brainres.2016.01.033] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 12/20/2022]
Abstract
The cerebral cortex is a critical target of the central noradrenergic system. The importance of norepinephrine (NE) in the regulation of cortical activity is underscored by clinical findings that involve this catecholamine and its receptor subtypes in the regulation of a large number of emotional and cognitive functions and illnesses. In this review, we highlight diverse effects of the LC/NE system in the mammalian cortex. Indeed, electrophysiological, pharmacological, and behavioral studies in the last few decades reveal that NE elicits a mixed repertoire of excitatory, inhibitory, and biphasic effects on the firing activity and transmitter release of cortical neurons. At the intrinsic cellular level, NE can produce a series of effects similar to those elicited by other monoamines or acetylcholine, associated with systemic arousal. At the synaptic level, NE induces numerous acute changes in synaptic function, and ׳gates' the induction of long-term plasticity of glutamatergic synapses, consisting in an enhancement of engaged and relevant cortical synapses and/or depression of unengaged synapses. Equally important in shaping cortical function, in many cortical areas NE promotes a characteristic, most often reversible, increase in the gain of local inhibitory synapses, whose extent and temporal properties vary between different areas and sometimes even between cortical layers of the same area. While we are still a long way from a comprehensive theory of the function of the LC/NE system, its cellular, synaptic, and plastic effects are consistent with the hypothesis that noradrenergic modulation is critical in coordinating the activity of cortical and subcortical circuits for the integration of sensory activity and working memory. This article is part of a Special Issue entitled SI: Noradrenergic System.
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Affiliation(s)
| | | | - Marco Atzori
- Universidad Autónoma de San Luis Potosí, México.
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11
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Cold acclimation allows regulation of chloride secretion in a eurythermic teleost fish Fundulus heteroclitus. Comp Biochem Physiol A Mol Integr Physiol 2015; 180:68-74. [DOI: 10.1016/j.cbpa.2014.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/10/2014] [Accepted: 11/11/2014] [Indexed: 11/17/2022]
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12
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Weigenand A, Schellenberger Costa M, Ngo HVV, Claussen JC, Martinetz T. Characterization of K-complexes and slow wave activity in a neural mass model. PLoS Comput Biol 2014; 10:e1003923. [PMID: 25392991 PMCID: PMC4230734 DOI: 10.1371/journal.pcbi.1003923] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 09/19/2014] [Indexed: 11/18/2022] Open
Abstract
NREM sleep is characterized by two hallmarks, namely K-complexes (KCs) during sleep stage N2 and cortical slow oscillations (SOs) during sleep stage N3. While the underlying dynamics on the neuronal level is well known and can be easily measured, the resulting behavior on the macroscopic population level remains unclear. On the basis of an extended neural mass model of the cortex, we suggest a new interpretation of the mechanisms responsible for the generation of KCs and SOs. As the cortex transitions from wake to deep sleep, in our model it approaches an oscillatory regime via a Hopf bifurcation. Importantly, there is a canard phenomenon arising from a homoclinic bifurcation, whose orbit determines the shape of large amplitude SOs. A KC corresponds to a single excursion along the homoclinic orbit, while SOs are noise-driven oscillations around a stable focus. The model generates both time series and spectra that strikingly resemble real electroencephalogram data and points out possible differences between the different stages of natural sleep.
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Affiliation(s)
- Arne Weigenand
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
| | - Michael Schellenberger Costa
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Hong-Viet Victor Ngo
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jens Christian Claussen
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Computational Systems Biology, Jacobs University Bremen, Bremen, Germany
| | - Thomas Martinetz
- Institute for Neuro- and Bioinformatics, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Science, University of Lübeck, Lübeck, Germany
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13
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Nasrallah FA, Low SMA, Lew SK, Chen K, Chuang KH. Pharmacological insight into neurotransmission origins of resting-state functional connectivity: α2-adrenergic agonist vs antagonist. Neuroimage 2014; 103:364-373. [PMID: 25241086 DOI: 10.1016/j.neuroimage.2014.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 08/11/2014] [Accepted: 09/03/2014] [Indexed: 12/15/2022] Open
Abstract
Resting-state functional connectivity MRI has emerged as a powerful tool for mapping large-scale neural networks based on synchronous BOLD signal; however, the neurobiological mechanisms are still unknown. To understand its neural substrates, especially the underlying neurotransmission, we applied pharmacological modulation with a receptor specific agonist and antagonist. Resting and evoked electrophysiology and BOLD signals in rat brains were measured under infusion of α2-adrenergic receptor agonist, medetomidine, the antagonist, atipamezole, and the vehicle individually. Both somatosensory BOLD activation and evoked potential were increased significantly under medetomidine compared to the vehicle while atipamezole slightly decreased both. The interhemispheric correlation at the resting state, in contrast, was suppressed by medetomidine but increased by atipamezole in regions with high receptor densities including the somatosensory cortex and thalamus. No change was seen in the caudate putamen, where receptor occupancy is low. The regional difference in connectivity was not related to cerebral blood flow, indicating that BOLD signal correlation is unlikely due to the vascular effects of the drugs. Resting intracortical recording exhibited agonist/antagonist dependent changes in beta and gamma bands that correlated with the BOLD functional connectivity measure. Our results confirm an important role of the adrenergic system on functional connectivity and suggest a neurotransmission basis of the phenomenon.
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Affiliation(s)
- Fatima A Nasrallah
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore
| | - Si-Min Amanda Low
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore
| | - Si Kang Lew
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore
| | - Kaina Chen
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore
| | - Kai-Hsiang Chuang
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore; Clinical Imaging Research Centre, National University of Singapore, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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14
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O’Donnell J, Zeppenfeld D, McConnell E, Pena S, Nedergaard M. Norepinephrine: a neuromodulator that boosts the function of multiple cell types to optimize CNS performance. Neurochem Res 2012; 37:2496-512. [PMID: 22717696 PMCID: PMC3548657 DOI: 10.1007/s11064-012-0818-x] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 05/16/2012] [Accepted: 05/26/2012] [Indexed: 12/23/2022]
Abstract
Norepinephrine (NE) is a neuromodulator that in multiple ways regulates the activity of neuronal and non-neuronal cells. NE participates in the rapid modulation of cortical circuits and cellular energy metabolism, and on a slower time scale in neuroplasticity and inflammation. Of the multiple sources of NE in the brain, the locus coeruleus (LC) plays a major role in noradrenergic signaling. Processes from the LC primarily release NE over widespread brain regions via non-junctional varicosities. We here review the actions of NE in astrocytes, microglial cells, and neurons based on the idea that the overarching effect of signaling from the LC is to maximize brain power, which is accomplished via an orchestrated cellular response involving most, if not all cell types in CNS.
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Affiliation(s)
- John O’Donnell
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Douglas Zeppenfeld
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Evan McConnell
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Salvador Pena
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Lukhanina EP, Pil’kevich NA. Modulating Action of an α2Adrenoreceptor Agonist, Clonidine, on Neuronal Activity and Synaptic Transmission in the Rat Prefrontal Cortex. NEUROPHYSIOLOGY+ 2011. [DOI: 10.1007/s11062-011-9225-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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16
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Marzo A, Bai J, Otani S. Neuroplasticity regulation by noradrenaline in mammalian brain. Curr Neuropharmacol 2011; 7:286-95. [PMID: 20514208 PMCID: PMC2811862 DOI: 10.2174/157015909790031193] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/28/2009] [Accepted: 10/20/2009] [Indexed: 11/22/2022] Open
Abstract
The neuromodulator noradrenaline (NA) is released in almost all brain areas in a highly diffused manner. Its action is slow, as it acts through G protein-coupled receptors, but its wide release in the brain makes NA a crucial regulator for various fundamental brain functions such as arousal, attention and memory processes [102]. To understand how NA acts in the brain to promote such diverse actions, it is necessary to dissect the cellular actions of NA at the level of single neurons as well as at the level of neuronal networks. In the present article, we will provide a compact review of the main literatures concerning the NA actions on neuroplasticity processes. Depending on which subtype of adrenoceptor is activated, NA differently affects intrinsic membrane properties of postsynaptic neurons and synaptic plasticity. For example, beta-adrenoceptor activation is mainly related to the potentiation of synaptic responses and learning and memory processes. alpha2-adrenoceptor activation may contribute to a high-order information processing such as executive function, but currently the direction of synaptic plasticity modification by alpha2-adrenoceptors has not been clearly determined. The activation of alpha1-adrenoceptors appears to mainly induce synaptic depression in the brain. But its physiological roles are still unclear: while its activation has been described as beneficial for cognitive functions, it may also exert detrimental effects in some brain structures such as the prefrontal cortex.
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Affiliation(s)
- Aude Marzo
- INSERM UMRS 952, 9 Quai St Bernard, 75005, Paris, France
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Pandipati S, Gire DH, Schoppa NE. Adrenergic receptor-mediated disinhibition of mitral cells triggers long-term enhancement of synchronized oscillations in the olfactory bulb. J Neurophysiol 2010; 104:665-74. [PMID: 20538781 DOI: 10.1152/jn.00328.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Norepinephrine (NE) is widely implicated in various forms of associative olfactory learning in rodents, including early learning preference in neonates. Here we used patch-clamp recordings in rat olfactory bulb slices to assess cellular actions of NE, examining both acute, short-term effects of NE as well as the relationship between these acute effects and long-term cellular changes that could underlie learning. Our focus for long-term effects was on synchronized gamma frequency (30-70 Hz) oscillations, shown in prior studies to be enhanced for up to an hour after brief exposure of a bulb slice to NE and neuronal stimulation. In terms of acute effects, we found that a dominant action of NE was to reduce inhibitory GABAergic transmission from granule cells (GCs) to output mitral cells (MCs). This disinhibition was also induced by clonidine, an agonist specific for alpha(2) adrenergic receptors (ARs). Acute NE-induced disinhibition of MCs appeared to be linked to long-term enhancement of gamma oscillations, based, first, on the fact that clonidine, but not agonists specific for other AR subtypes, mimicked NE's long-term actions. In addition, the alpha(2) AR-specific antagonist yohimbine blocked the long-term enhancement of the oscillations due to NE. Last, brief exposure of the slice to the GABA(A) receptor antagonist gabazine, to block inhibitory synapses directly, also induced the long-term changes. Acute disinhibition is a plausible permissive effect of NE leading to olfactory learning, because, when combined with exposure to a specific odor, it should lead to neuron-specific increases in intracellular calcium of the type generally associated with long-term synaptic modifications.
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Affiliation(s)
- Sruthi Pandipati
- Neuroscience Program, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045, USA
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Delivoria-Papadopoulos M, Mishra OP. Mechanism of Post-Translational Modification by Tyrosine Phosphorylation of Apoptotic Proteins During Hypoxia in the Cerebral Cortex of Newborn Piglets. Neurochem Res 2009; 35:76-84. [DOI: 10.1007/s11064-009-0032-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 06/27/2009] [Indexed: 11/29/2022]
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19
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Dong C, Godwin DW, Brennan PA, Hegde AN. Protein kinase Calpha mediates a novel form of plasticity in the accessory olfactory bulb. Neuroscience 2009; 163:811-24. [PMID: 19580852 DOI: 10.1016/j.neuroscience.2009.06.069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 06/29/2009] [Accepted: 06/30/2009] [Indexed: 11/27/2022]
Abstract
Modification of synapses in the accessory olfactory bulb (AOB) is believed to underlie pheromonal memory that enables mate recognition in mice. The memory, which is acquired with single-trial learning, forms only with coincident noradrenergic and glutamatergic inputs to the AOB. The mechanisms by which glutamate and norepinephrine (NE) alter the AOB synapses are not well understood. Here we present results that not only reconcile the earlier, seemingly contradictory, observations on the role of glutamate and NE in changing the AOB synapses, but also reveal novel mechanisms of plasticity. Our studies suggest that initially, glutamate acting at Group II metabotropic receptors and NE acting at alpha(2)-adrenergic receptors inhibit N-type and R-type Ca(2+) channels in mitral cells via a G-protein. The N-type and R-type Ca(2+) channel inhibition is reversed by activation of alpha(1)-adrenergic receptors and protein kinase Calpha (PKCalpha). Based on these results, we propose a hypothetical model for a new kind of synaptic plasticity in the AOB that accounts for the previous behavioral data on pheromonal memory. According to this model, initial inhibition of the Ca(2+) channels suppresses the GABAergic inhibitory feedback to mitral cells, causing disinhibition and Ca(2+) influx. NE also activates phospholipase C (PLC) through alpha(1)-adrenergic receptors generating inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Calcium and DAG together activate PKCalpha which switches the disinhibition to increased inhibition of mitral cells. Thus, PKCalpha is likely to be a coincidence detector integrating glutamate and NE input in the AOB and bridging the short-term signaling to long-term structural changes resulting in enhanced inhibition of mitral cells that is thought to underlie memory formation.
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Affiliation(s)
- C Dong
- Department of Neurobiology and Anatomy, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157-0001, USA
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20
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Dinh L, Nguyen T, Salgado H, Atzori M. Norepinephrine homogeneously inhibits alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate- (AMPAR-) mediated currents in all layers of the temporal cortex of the rat. Neurochem Res 2009; 34:1896-906. [PMID: 19357950 DOI: 10.1007/s11064-009-9966-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 03/26/2009] [Indexed: 11/25/2022]
Abstract
The primary auditory cortex is subject to the modulation of numerous neurotransmitters including norepinephrine (NE), which has been shown to decrease cellular excitability by yet unclear mechanisms. We investigated the possibility that NE directly affects excitatory glutamatergic synapses. We found that bath applications of NE (20 microM) decreased glutamatergic excitatory post-synaptic currents (EPSCs) in all cortical layers. Changes in the kinetics of synaptic EPSCs, invariance of pair pulse ratio and of the coefficient-of-variation, together with the decrease of responses to pressure-application of AMPA (500 microM), indicated the postsynaptic nature of the adrenergic effect. Pharmacological experiments suggested that the NE-induced depression of EPSCs is caused by the activation of alpha1 adrenoceptors, PLC, and a Ca(2+)-independent PKC. We speculate that the decrease in temporal cortex excitability might promote a posterior-to-anterior shift in cortical activation together with a decrease in spontaneous background activity, resulting eventually in more effective sensory processing.
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Affiliation(s)
- Lu Dinh
- The University of Texas at Dallas, Richardson, TX 75080, USA
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21
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In vitro and in vivo profiling of fadolmidine, a novel potent α2-adrenoceptor agonist with local mode of action. Eur J Pharmacol 2008; 599:65-71. [DOI: 10.1016/j.ejphar.2008.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 09/12/2008] [Accepted: 10/02/2008] [Indexed: 11/22/2022]
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22
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Vibert YM, Ashraf QM, Mishra OP, Delivoria-Papadopoulos M. Mechanism of Ca2+-influx and Ca2+/calmodulin-dependent protein kinase IV activity during in utero hypoxia in cerebral cortical neuronal nuclei of the guinea pig fetus at term. Neurosci Lett 2008; 440:227-31. [PMID: 18571321 DOI: 10.1016/j.neulet.2008.05.095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 05/22/2008] [Accepted: 05/24/2008] [Indexed: 10/22/2022]
Abstract
Previously we showed that following hypoxia there is an increase in nuclear Ca(2+)-influx and Ca(2+)/calmodulin-dependent protein kinase IV activity (CaMK IV) in the cerebral cortex of term guinea pig fetus. The present study tests the hypothesis that clonidine administration will prevent hypoxia-induced increased neuronal nuclear Ca(2+)-influx and increased CaMK IV activity, by blocking high-affinity Ca(2+)-ATPase. Studies were conducted in 18 pregnant guinea pigs at term, normoxia (Nx, n=6), hypoxia (Hx, n=6) and clonidine with Hx (Hx+Clo, n=6). The pregnant guinea pig was exposed to a decreased FiO(2) of 0.07 for 60 min. Clonidine, an imidazoline inhibitor of high-affinity Ca(2+)-ATPase, was administered 12.5 microg/kg IP 30 min prior to hypoxia. Hypoxia was determined biochemically by ATP and phosphocreatine (PCr) levels. Nuclei were isolated and ATP-dependent (45)Ca(2+)-influx was determined. CaMK IV activity was determined by (33)P-incorporation into syntide 2 for 2 min at 37 degrees C in a medium containing 50mM HEPES (pH 7.5), 2mM DTT, 40muM syntide 2, 0.2mM (33)P-ATP, 10mM magnesium acetate, 5 microM PKI 5-24, 2 microM PKC 19-36 inhibitor peptides, 1 microM microcystine LR, 200 microM sodium orthovanadate and either 1mM EGTA (for CaMK IV-independent activity) or 0.8mM CaCl(2) and 1mM calmodulin (for total activity). ATP (mumoles/gbrain) values were significantly different in the Nx (4.62+/-0.2), Hx (1.65+/-0.2, p<0.05 vs. Nx), and Hx+Clo (1.92+/-0.6, p<0.05 vs. Nx). PCr (mumoles/g brain) values in the Nx (3.9+/-0.1), Hx (1.10+/-0.3, p<0.05 vs. Nx), and Hx+Clo (1.14+/-0.3, p<0.05 vs. Nx). There was a significant difference between nuclear Ca(2+)-influx (pmoles/mg protein/min) in Nx (3.98+/-0.4), Hx (10.38+/-0.7, p<0.05 vs. Nx), and Hx+Clo (7.35+/-0.9, p<0.05 vs. Nx, p<0.05 vs. Hx), and CaM KIV (pmoles/mg protein/min) in Nx (1314.00+/-195.4), Hx (2315.14+/-148.5, p<0.05 vs. Nx), and Hx+Clo (1686.75+/-154.3, p<0.05 vs. Nx, p<0.05 vs. Hx). We conclude that the mechanism of hypoxia-induced increased nuclear Ca(2+)-influx is mediated by high-affinity Ca(2+)-ATPase and that CaMK IV activity is nuclear Ca(2+)-influx-dependent. We speculate that hypoxia-induced alteration of high-affinity Ca(2+)-ATPase is a key step that triggers nuclear Ca(2+)-influx, leading to CREB protein-mediated increased expression of apoptotic proteins and hypoxic neuronal death.
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Affiliation(s)
- Yanick M Vibert
- Department of Pediatrics, Drexel University College of Medicine and St. Christopher's Hospital for Children, Philadelphia, PA 19102, United States.
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Effect of hypoxia on expression of apoptotic proteins in nuclear, mitochondrial and cytosolic fractions of the cerebral cortex of newborn piglets: the role of nuclear Ca++ -influx. Neurochem Res 2008; 33:1196-204. [PMID: 18293086 DOI: 10.1007/s11064-007-9568-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2007] [Indexed: 02/03/2023]
Abstract
We have shown that hypoxia results in increased influx of nuclear Ca++ and increased expression of nuclear apoptotic proteins. The present study tests the hypothesis that hypoxia alters the distribution of pro-apoptotic proteins Bad and Bax, and the anti-apoptotic proteins Bcl-xl, and Bcl-2 in the nuclear, mitochondrial and cytosolic compartments of the cerebral cortex of newborn piglets and the administration of Clonidine, an inhibitor of high affinity nuclear Ca++ -ATPase, will prevent the hypoxia-induced increase in apoptotic proteins' expression. Studies were conducted in 19 newborn piglets, 6 normoxic (Nx), 7 hypoxic and 6 Clonidine-treated hypoxic (Hx-Clo). Tissue hypoxia was documented biochemically by measuring cerebral tissue ATP and phosphocreatine (PCr) levels. Bax and Bad protein expression increased in all the three compartments during hypoxia, while there was no significant change in the expression of anti-apoptotic proteins Bcl-2 and Bcl-xl. In Clonidine pretreated hypoxic group, the hypoxia-induced increased expression of pro-apoptotic proteins Bad and Bax was prevented in all the three fractions. We conclude that hypoxia results in increased expression of pro-apoptotic proteins in nuclear, mitochondrial and cytosolic compartments and that the increased expression of pro-apoptotic proteins during hypoxia is nuclear Ca++ -influx-dependent. We propose that during hypoxia the increased ratio of (pro-apoptotic Bad and Bax/anti-apoptotic Bcl-xl and Bcl-2) in all the three compartments, will lead to altered mitochondrial and nuclear membrane permeability as well as caspase-9 activation in the cytosolic compartment.
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Bengtsson F, Jörntell H. Ketamine and xylazine depress sensory-evoked parallel fiber and climbing fiber responses. J Neurophysiol 2007; 98:1697-705. [PMID: 17615140 DOI: 10.1152/jn.00057.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The last few years have seen an increase in the variety of in vivo experiments used for studying cerebellar physiological mechanisms. A combination of ketamine and xylazine has become a particularly popular form of anesthesia. However, because nonanesthetized control conditions are lacking in these experiments, so far there has been no evaluation of the effects of these drugs on the physiological activity in the cerebellar neuronal network. In the present study, we used the mossy fiber, parallel fiber, and climbing fiber field potentials evoked in the nonanesthetized, decerebrated rat to serve as a control condition against which the effects of intravenous drug injections could be compared. All anesthetics were applied at doses required for normal maintenance of anesthesia. We found that ketamine substantially depressed the evoked N3 field potential, which is an indicator of the activity in the parallel fiber synapses (-40%), and nearly completely abolished evoked climbing fiber field potentials (-90%). Xylazine severely depressed the N3 field (-75%) and completely abolished the climbing fiber field (-100%). In a combination commonly used for general anesthesia (20:1), ketamine-xylazine injections also severely depressed the N3 field (-75%) and nearly completely abolished the climbing fiber field (-90%). We also observed that lowered body and surface temperatures (<34 degrees C) resulted in a substantial depression of the N3 field (-50%). These results urge for some caution in the interpretations of studies on cerebellar network physiology performed in animals anesthetized with these drugs.
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Affiliation(s)
- Fredrik Bengtsson
- Department of Experimental Medical Science, Section for Neuroscience, BMC F10, Lund University, Tornavägen 10, SE-221 84 Lund, Sweden
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Hornick K, Chang E, Zubrow AB, Mishra OP, Delivoria-Papadopoulos M. Mechanism of Ca(2+)/calmodulin-dependent protein kinase IV activation and of cyclic AMP response element binding protein phosphorylation during hypoxia in the cerebral cortex of newborn piglets. Brain Res 2007; 1150:40-5. [PMID: 17428448 DOI: 10.1016/j.brainres.2007.02.079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 02/15/2007] [Accepted: 02/28/2007] [Indexed: 11/30/2022]
Abstract
Previously we showed that hypoxia results in increased neuronal nuclear Ca(2+) influx, Ca(2+)/calmodulin-dependent protein kinase IV activity (CaM KIV) and phosphorylation of c-AMP response element binding (CREB) protein. The aim of the present study was to understand the importance of neuronal nuclear Ca(2+) in the role of CaM KIV activation and CREB protein phosphorylation associated with hypoxia. To accomplish this the present study tests the hypothesis that clonidine administration will block increased nuclear Ca(2+) influx by inhibiting high affinity Ca(2+)/ATPase and prevent increased CaM KIV activity and CREB phosphorylation in the neuronal nuclei of the cerebral cortex of hypoxic newborn piglets. To accomplish this piglets were divided in three groups: normoxic, hypoxic, and hypoxic-treated with clonidine. The piglets that were in the Hx+Cl group received clonidine 5 min prior to hypoxia. Cerebral tissue hypoxia was confirmed biochemically by tissue levels of ATP and phosphocreatine (PCr). The data show that clonidine prevents hypoxia-induced increase in CaM KIV activity and CREB protein phosphorylation. We conclude that the mechanism of hypoxia-induced activation of CaM KIV and CREB phosphorylation is nuclear Ca(2+) influx mediated. We speculate that nuclear Ca(2+) influx is a key step that triggers CREB mediated transcription of apoptotic proteins and hypoxic mediated neuronal death.
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Affiliation(s)
- Kristie Hornick
- Drexel University College of Medicine Division of Neonatology Department of Pediatrics Mail Stop 1029 245 N, 15th Street Philadelphia, PA 19102, USA.
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Halperin JM, Schulz KP. Revisiting the role of the prefrontal cortex in the pathophysiology of attention-deficit/hyperactivity disorder. Psychol Bull 2006; 132:560-81. [PMID: 16822167 DOI: 10.1037/0033-2909.132.4.560] [Citation(s) in RCA: 287] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Most neural models for the pathophysiology of attention-deficit/hyperactivity disorder (ADHD) have centered on the prefrontal cortex and its interconnections with the striatum and other subcortical structures. However, research only partially supports these models, and they do not correspond with the development of the prefrontal cortex and its interrelated neurocircuitry. The neural and functional development of the prefrontal cortex more closely parallels recovery from ADHD as indicated by the developmental remission of symptomatology. The authors hypothesize that ADHD is due to noncortical dysfunction that manifests early in ontogeny, remains static throughout the lifetime, and is not associated with the remission of symptomatology. Data supporting this neurodevelopmental model of prefrontal cortex function in ADHD are reviewed. Research and treatment implications are discussed.
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Affiliation(s)
- Jeffrey M Halperin
- Department of Psychology, Queens College of the City University of New York, Flushing, NY 11367, USA.
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