1
|
Kanigowski D, Urban-Ciecko J. Conditioning and pseudoconditioning differently change intrinsic excitability of inhibitory interneurons in the neocortex. Cereb Cortex 2024; 34:bhae109. [PMID: 38572735 PMCID: PMC10993172 DOI: 10.1093/cercor/bhae109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 04/05/2024] Open
Abstract
Many studies indicate a broad role of various classes of GABAergic interneurons in the processes related to learning. However, little is known about how the learning process affects intrinsic excitability of specific classes of interneurons in the neocortex. To determine this, we employed a simple model of conditional learning in mice where vibrissae stimulation was used as a conditioned stimulus and a tail shock as an unconditioned one. In vitro whole-cell patch-clamp recordings showed an increase in intrinsic excitability of low-threshold spiking somatostatin-expressing interneurons (SST-INs) in layer 4 (L4) of the somatosensory (barrel) cortex after the conditioning paradigm. In contrast, pseudoconditioning reduced intrinsic excitability of SST-LTS, parvalbumin-expressing interneurons (PV-INs), and vasoactive intestinal polypeptide-expressing interneurons (VIP-INs) with accommodating pattern in L4 of the barrel cortex. In general, increased intrinsic excitability was accompanied by narrowing of action potentials (APs), whereas decreased intrinsic excitability coincided with AP broadening. Altogether, these results show that both conditioning and pseudoconditioning lead to plastic changes in intrinsic excitability of GABAergic interneurons in a cell-specific manner. In this way, changes in intrinsic excitability can be perceived as a common mechanism of learning-induced plasticity in the GABAergic system.
Collapse
Affiliation(s)
- Dominik Kanigowski
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Joanna Urban-Ciecko
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093 Warsaw, Poland
| |
Collapse
|
2
|
Ye H, Liu ZX, He YJ, Wang X. Effects of M currents on the persistent activity of pyramidal neurons in mouse primary auditory cortex. J Neurophysiol 2022; 127:1269-1278. [PMID: 35294269 DOI: 10.1152/jn.00332.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuronal persistent activity (PA) is a common phenomenon observed in many types of neurons. PA can be induced in neurons in the mouse auditory nucleus by activating cholinergic receptors with carbachol (CCh), a dual muscarinic and nicotinic receptor agonist. PA is presumed to be associated with learning-related auditory plasticity at the cellular level. However, the mechanism is not clearly understood. Many studies have reported that muscarinic cholinergic receptor agonists inhibit muscarinic-sensitive potassium channels (M channels). Potassium influx through M channels produces potassium currents, called M currents, which play an essential role in regulating neural excitability and synaptic plasticity. Further study is needed to determine whether M currents affect the PA of auditory central neurons and provide additional analysis of the variations in electrophysiological properties. We used in vitro whole-cell patch-clamp recordings in isolated mouse brain slices to investigate the effects of M currents on the PA in pyramidal neurons in layer V of the primary auditory cortex (AI-L5). We found that blocking M currents with XE991 depolarized the AI-L5 pyramidal neurons, which significantly increased the input resistance. The active threshold and threshold intensity were significantly reduced, indicating that the intrinsic excitability was enhanced. Our results also showed that blocking M currents with XE991 switched the neuronal firing patterns in the AI-L5 pyramidal neurons from regular-spiking to intrinsic-bursting. Blocking M currents facilitated PA by increasing the plateau potential and enhancing intrinsic excitability. Our results suggested that blocking M currents might facilitate the PA in AI-L5 pyramidal neurons, which underlies auditory plasticity.
Collapse
Affiliation(s)
- Huan Ye
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Zhen-Xu Liu
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Ya-Jie He
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Xin Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| |
Collapse
|
3
|
Chronic Stress Induces Maladaptive Behaviors by Activating Corticotropin-Releasing Hormone Signaling in the Mouse Oval Bed Nucleus of the Stria Terminalis. J Neurosci 2020; 40:2519-2537. [PMID: 32054675 DOI: 10.1523/jneurosci.2410-19.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/16/2020] [Accepted: 01/16/2020] [Indexed: 12/21/2022] Open
Abstract
The bed nucleus of the stria terminalis (BNST) is a forebrain region highly responsive to stress that expresses corticotropin-releasing hormone (CRH) and is implicated in mood disorders, such as anxiety. However, the exact mechanism by which chronic stress induces CRH-mediated dysfunction in BNST and maladaptive behaviors remains unclear. Here, we first confirmed that selective acute optogenetic activation of the oval nucleus BNST (ovBNST) increases maladaptive avoidance behaviors in male mice. Next, we found that a 6 week chronic variable mild stress (CVMS) paradigm resulted in maladaptive behaviors and increased cellular excitability of ovBNST CRH neurons by potentiating mEPSC amplitude, altering the resting membrane potential, and diminishing M-currents (a voltage-gated K+ current that stabilizes membrane potential) in ex vivo slices. CVMS also increased c-fos+ cells in ovBNST following handling. We next investigated potential molecular mechanism underlying the electrophysiological effects and observed that CVMS increased CRH+ and pituitary adenylate cyclase-activating polypeptide+ (PACAP; a CRH upstream regulator) cells but decreased striatal-enriched protein tyrosine phosphatase+ (a STEP CRH inhibitor) cells in ovBNST. Interestingly, the electrophysiological effects of CVMS were reversed by CRHR1-selective antagonist R121919 application. CVMS also activated protein kinase A (PKA) in BNST, and chronic infusion of the PKA-selective antagonist H89 into ovBNST reversed the effects of CVMS. Coadministration of the PKA agonist forskolin prevented the beneficial effects of R121919. Finally, CVMS induced an increase in surface expression of phosphorylated GluR1 (S845) in BNST. Collectively, these findings highlight a novel and indispensable stress-induced role for PKA-dependent CRHR1 signaling in activating BNST CRH neurons and mediating maladaptive behaviors.SIGNIFICANCE STATEMENT Chronic stress and acute activation of oval bed nucleus of the stria terminalis (ovBNST) induces maladaptive behaviors in rodents. However, the precise molecular and electrophysiological mechanisms underlying these effects remain unclear. Here, we demonstrate that chronic variable mild stress activates corticotropin-releasing hormone (CRH)-associated stress signaling and CRH neurons in ovBNST by potentiating mEPSC amplitude and decreasing M-current in male mice. These electrophysiological alterations and maladaptive behaviors were mediated by BNST protein kinase A-dependent CRHR1 signaling. Our results thus highlight the importance of BNST CRH dysfunction in chronic stress-induced disorders.
Collapse
|
4
|
Ma Z, Gao F, Larsen B, Gao M, Luo Z, Chen D, Ma X, Qiu S, Zhou Y, Xie J, Xi ZX, Wu J. Mechanisms of cannabinoid CB 2 receptor-mediated reduction of dopamine neuronal excitability in mouse ventral tegmental area. EBioMedicine 2019; 42:225-237. [PMID: 30952618 PMCID: PMC6491419 DOI: 10.1016/j.ebiom.2019.03.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/24/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND We have recently reported that activation of cannabinoid type 2 receptors (CB2Rs) reduces dopamine (DA) neuron excitability in mouse ventral tegmental area (VTA). Here, we elucidate the underlying mechanisms. METHODS Patch-clamp recordings were performed in mouse VTA slices and dissociated single VTA DA neurons. FINDINGS Using cell-attached recording in VTA slices, bath-application of CB2R agonists (JWH133 or five other CB2R agonists) significantly reduced VTA DA neuron action potential (AP) firing rate. Under the patch-clamp whole-cell recording model, JWH133 (10 μM) mildly reduced the frequency of miniature excitatory postsynaptic currents (mEPSCs) but not miniature inhibitory postsynaptic currents (mIPSCs). JWH133 also did not alter evoked EPSCs or IPSCs. In freshly dissociated VTA DA neurons, JWH133 reduced AP firing rate, delayed AP initiation and enhanced AP after-hyperpolarization. In voltage-clamp recordings, JWH133 (1 μM) enhanced M-type K+ currents and this effect was absent in CB2-/- mice and abolished by co-administration of a selective CB2R antagonist (10 μM, AM630). CB2R-mediated inhibition in VTA DA neuron firing can be mimicked by M-current opener (10 μM retigabine) and blocked by M-current blocker (30 μM XE991). In addition, enhancement of neuronal cAMP by forskolin (10 μM) reduced M-current and increased DA neuron firing rate. Finally, pharmacological block of synaptic transmission by NBQX (10 μM), D-APV (50 μM) and picrotoxin (100 μM) in VTA slices failed to prevent CB2R-mediated inhibition, while intracellular infusion of guanosine 5'-O-2-thiodiphosphate (600 μM, GDP-β-S) through recording electrode to block postsynaptic G-protein function prevented JWH133-induced reduction in AP firing. INTERPRETATION Our results suggest that CB2Rs modulate VTA DA neuron excitability mainly through an intrinsic mechanism, including a CB2R-mediated reduction of intracellular cAMP, and in turn enhancement of M-type K+ currents. FUND: This research was supported by the Barrow Neuroscience Foundation, the BNI-BMS Seed Fund, and CNSF (81771437).
Collapse
Affiliation(s)
- Zegang Ma
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Fenfei Gao
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Brett Larsen
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Ming Gao
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Zhihua Luo
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China
| | - Dejie Chen
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong 527300, China
| | - Xiaokuang Ma
- Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Shenfeng Qiu
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Yu Zhou
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China
| | - Junxia Xie
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD 21224, USA
| | - Jie Wu
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao 266071, China; Department of Neurobiology, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong 210854, China; Department of Neurology, Yunfu People's Hospital, Yunfu, Guangdong 527300, China.
| |
Collapse
|
5
|
Paz RM, Tubert C, Stahl A, Díaz AL, Etchenique R, Murer MG, Rela L. Inhibition of striatal cholinergic interneuron activity by the Kv7 opener retigabine and the nonsteroidal anti-inflammatory drug diclofenac. Neuropharmacology 2018; 137:309-321. [PMID: 29758221 DOI: 10.1016/j.neuropharm.2018.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 04/26/2018] [Accepted: 05/07/2018] [Indexed: 11/18/2022]
Abstract
Striatal cholinergic interneurons provide modulation to striatal circuits involved in voluntary motor control and goal-directed behaviors through their autonomous tonic discharge and their firing "pause" responses to novel and rewarding environmental events. Striatal cholinergic interneuron hyperactivity was linked to the motor deficits associated with Parkinson's disease and the adverse effects of chronic antiparkinsonian therapy like l-DOPA-induced dyskinesia. Here we addressed whether Kv7 channels, which provide negative feedback to excitation in other neuron types, are involved in the control of striatal cholinergic interneuron tonic activity and response to excitatory inputs. We found that autonomous firing of striatal cholinergic interneurons is not regulated by Kv7 channels. In contrast, Kv7 channels limit the summation of excitatory postsynaptic potentials in cholinergic interneurons through a postsynaptic mechanism. Striatal cholinergic interneurons have a high reserve of Kv7 channels, as their opening using pharmacological tools completely silenced the tonic firing and markedly reduced their intrinsic excitability. A strong inhibition of striatal cholinergic interneurons was also observed in response to the anti-inflammatory drugs diclofenac and meclofenamic acid, however, this effect was independent of Kv7 channels. These data bring attention to new potential molecular targets and pharmacological tools to control striatal cholinergic interneuron activity in pathological conditions where they are believed to be hyperactive, including Parkinson's disease.
Collapse
Affiliation(s)
- Rodrigo Manuel Paz
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina
| | - Cecilia Tubert
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina
| | - Agostina Stahl
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina
| | - Analía López Díaz
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina
| | - Roberto Etchenique
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CONICET, Ciudad Universitaria Pabellón 2, AR1428EHA Buenos Aires, Argentina
| | - Mario Gustavo Murer
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina
| | - Lorena Rela
- Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisiología y Biofísica "Bernardo Houssay" (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Buenos Aires 1121, Argentina.
| |
Collapse
|
6
|
Urban KR, Valentino RJ. Age- and Sex-Dependent Impact of Repeated Social Stress on Intrinsic and Synaptic Excitability of the Rat Prefrontal Cortex. Cereb Cortex 2017; 27:244-253. [PMID: 28013234 PMCID: PMC5939192 DOI: 10.1093/cercor/bhw388] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 11/12/2016] [Indexed: 11/14/2022] Open
Abstract
Stress is implicated in psychiatric illnesses that are characterized by impairments in cognitive functions that are mediated by the medial prefrontal cortex (mPFC). Because sex and age determine stress vulnerability, the effects of repeated social stress occurring during early adolescence, mid-adolescence, or adulthood on the cellular properties of male and female rat mPFC Layer V neurons in vitro were examined. Repeated resident-intruder stress produced age- and sex-specific effects on mPFC intrinsic and synaptic excitability. Mid-adolescents were particularly vulnerable to effects on intrinsic excitability. The maximum number of action potentials (APs) evoked by increasing current intensity was robustly decreased in stressed male and female mid-adolescent rats compared with age-matched controls. These effects were associated with stress-induced changes in AP half-width, amplitude, threshold, and input resistance. Social stress at all ages generally decreased synaptic excitability by decreasing the amplitude of spontaneous excitatory postsynaptic potentials. The results suggest that whereas social stress throughout life can diminish the influence of afferents driving the mPFC, social stress during mid-adolescence additionally affects intrinsic characteristics of mPFC neurons that determine excitability. The depressant effects of social stress on intrinsic and synaptic mPFC neurons may underlie its ability to affect executive functions and emotional responses, particularly during adolescence.
Collapse
Affiliation(s)
- Kimberly R. Urban
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Rita J. Valentino
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| |
Collapse
|
7
|
Hu P, Liu J, Yasrebi A, Gotthardt JD, Bello NT, Pang ZP, Roepke TA. Gq Protein-Coupled Membrane-Initiated Estrogen Signaling Rapidly Excites Corticotropin-Releasing Hormone Neurons in the Hypothalamic Paraventricular Nucleus in Female Mice. Endocrinology 2016; 157:3604-20. [PMID: 27387482 PMCID: PMC5007888 DOI: 10.1210/en.2016-1191] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/01/2016] [Indexed: 02/07/2023]
Abstract
CRH neurons in the hypothalamic paraventricular nucleus (PVN) play a central role in regulating the hypothalamus-pituitary-adrenal (HPA) axis and are directly influenced by 17β-estradiol (E2). Although compelling evidence has suggested the existence of membrane-associated estrogen receptors (mERs) in hypothalamic and other central nervous system neurons, it remains unknown whether E2 impacts CRH neuronal excitability through this mechanism. The purpose of the current study is to examine the existence and function of mER signaling in PVN CRH neurons. Whole-cell recordings were made from CRH neurons identified by Alexa Fluor 594 labeling and post hoc immunostaining in ovariectomized female mice. E2 (100nM) rapidly suppressed the M-current (a voltage-dependent K(+) current) and potentiated glutamatergic excitatory postsynaptic currents. The putative Gq-coupled mER (Gq-mER) characterized in hypothalamic proopiomelanocortin neurons initiates a phospholipase C-protein kinase C-protein kinase A pathway; therefore, we examined the involvement of this pathway using selective inhibitors. Indeed, the ER antagonist ICI 182780 and inhibitors of Gq-phospholipase C-protein kinase C-protein kinase A blocked E2's actions, suggesting dependence on the Gq-mER. Furthermore, STX, a selective ligand for the Gq-mER, mimicked E2's actions. Finally, to examine the in vivo effect of Gq-mER activation, E2 or STX injection increased c-fos expression in CRH neurons in the PVN, suggesting CRH neuronal activation. This corresponded to an increase in plasma corticosterone. We conclude that the Gq-mER plays a critical role in the rapid regulation of CRH neuronal activity and the HPA axis. Our findings provide a potential underlying mechanism for E2's involvement in the pathophysiology of HPA-associated mood disorders.
Collapse
Affiliation(s)
- Pu Hu
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Ji Liu
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Ali Yasrebi
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Juliet D Gotthardt
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Nicholas T Bello
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Zhiping P Pang
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Troy A Roepke
- Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| |
Collapse
|
8
|
KV7 Channels Regulate Firing during Synaptic Integration in GABAergic Striatal Neurons. Neural Plast 2015; 2015:472676. [PMID: 26113994 PMCID: PMC4465714 DOI: 10.1155/2015/472676] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/07/2015] [Indexed: 11/17/2022] Open
Abstract
Striatal projection neurons (SPNs) process motor and cognitive information. Their activity is affected by Parkinson's disease, in which dopamine concentration is decreased and acetylcholine concentration is increased. Acetylcholine activates muscarinic receptors in SPNs. Its main source is the cholinergic interneuron that responds with a briefer latency than SPNs during a cortical command. Therefore, an important question is whether muscarinic G-protein coupled receptors and their signaling cascades are fast enough to intervene during synaptic responses to regulate synaptic integration and firing. One of the most known voltage dependent channels regulated by muscarinic receptors is the KV7/KCNQ channel. It is not known whether these channels regulate the integration of suprathreshold corticostriatal responses. Here, we study the impact of cholinergic muscarinic modulation on the synaptic response of SPNs by regulating KV7 channels. We found that KV7 channels regulate corticostriatal synaptic integration and that this modulation occurs in the dendritic/spines compartment. In contrast, it is negligible in the somatic compartment. This modulation occurs on sub- and suprathreshold responses and lasts during the whole duration of the responses, hundreds of milliseconds, greatly altering SPNs firing properties. This modulation affected the behavior of the striatal microcircuit.
Collapse
|
9
|
Springer SJ, Burkett BJ, Schrader LA. Modulation of BK channels contributes to activity-dependent increase of excitability through MTORC1 activity in CA1 pyramidal cells of mouse hippocampus. Front Cell Neurosci 2015; 8:451. [PMID: 25628536 PMCID: PMC4292769 DOI: 10.3389/fncel.2014.00451] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 12/13/2014] [Indexed: 11/15/2022] Open
Abstract
Memory acquisition and synaptic plasticity are accompanied by changes in the intrinsic excitability of CA1 pyramidal neurons. These activity-dependent changes in excitability are mediated by modulation of intrinsic currents which alters the responsiveness of the cell to synaptic inputs. The afterhyperpolarization (AHP), a major contributor to the regulation of neuronal excitability, is reduced in animals that have acquired several types of hippocampus-dependent memory tasks and also following synaptic potentiation by high frequency stimulation. BK channels underlie the fast AHP and contribute to spike repolarization, and this AHP is reduced in animals that successfully acquired trace-eyeblink conditioning. This suggests that BK channel function is activity-dependent, but the mechanisms are unknown. In this study, we found that blockade of BK channels with paxilline (10 μM) decreased IAHP amplitude and increased spike half-width and instantaneous frequency in response to a +100 pA depolarization. In addition, induction of long term potentiation (LTP) by theta burst stimulation (TBS) in CA1 pyramidal neurons reduced BK channel’s contribution to IAHP, spike repolarization, and instantaneous frequency. This result indicates that BK channel activity is decreased following synaptic potentiation. Interestingly, blockade of mammalian target of rapamycin (MTORC1) with rapamycin (400 nM) following synaptic potentiation restored BK channel function, suggesting a role for protein translation in signaling events which decreased postsynaptic BK channel activity following synaptic potentiation.
Collapse
Affiliation(s)
| | - Brian J Burkett
- Neuroscience Program, Tulane University New Orleans, LA, USA
| | - Laura A Schrader
- Neuroscience Program, Tulane University New Orleans, LA, USA ; Department of Cell and Molecular Biology, Tulane University New Orleans, LA, USA
| |
Collapse
|
10
|
Szücs A, Huerta R. Differential effects of static and dynamic inputs on neuronal excitability. J Neurophysiol 2015; 113:232-43. [PMID: 25274346 DOI: 10.1152/jn.00226.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The intrinsic excitability of neurons is known to be dynamically regulated by activity-dependent plasticity and homeostatic mechanisms. Such processes are commonly analyzed in the context of input-output functions that describe how neurons fire in response to constant levels of current. However, it is not well understood how changes of excitability as observed under static inputs translate to the function of the same neurons in their natural synaptic environment. Here we performed a computational study and hybrid experiments on rat bed nucleus of stria terminalis neurons to compare the two scenarios. The inward rectifying Kir current (IKir) and the hyperpolarization-activated cation current (Ih) were found to be considerably more effective in regulating the firing under synaptic inputs than under static stimuli. This prediction was experimentally confirmed by dynamic-clamp insertion of a synthetic inwardly rectifying Kir current into the biological neurons. At the same time, ionic currents that activate with depolarization were more effective regulating the firing under static inputs. When two intrinsic currents are concurrently altered such as those under homeostatic regulation, the effects in firing responses under static vs. dynamic inputs can be even more contrasting. Our results show that plastic or homeostatic changes of intrinsic membrane currents can shape the current step responses of neurons and their firing under synaptic inputs in a differential manner.
Collapse
Affiliation(s)
- Attila Szücs
- BioCircuits Institute, University of California, San Diego, La Jolla, California; and Balaton Limnological Institute, Center of Ecology of the Hungarian Academy of Sciences, Tihany, Hungary
| | - Ramon Huerta
- BioCircuits Institute, University of California, San Diego, La Jolla, California; and
| |
Collapse
|
11
|
Xu L, Zhang S, Fan H, Zhong Z, Li X, Jin X, Chang Q. ClC-3 chloride channel in hippocampal neuronal apoptosis. Neural Regen Res 2013; 8:3047-54. [PMID: 25206625 PMCID: PMC4146203 DOI: 10.3969/j.issn.1673-5374.2013.32.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/10/2013] [Indexed: 12/18/2022] Open
Abstract
Over-production of nitric oxide is pathogenic for neuronal apoptosis around the ischemic area fol-lowing ischemic brain injury. In this study, an apoptotic model in rat hippocampal neurons was tablished by 0.5 mmol/L 3-morpholinosyndnomine (SIN-1), a nitric oxide donor. The models were then cultured with 0.1 mmol/L of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; the chloride channel blocker) for 18 hours. Neuronal survival was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and apoptosis was assayed by Hoechst 33342-labeled neuronal DNA fluorescence staining. Western blot analysis and immunoche-nescence staining were applied to determine the changes of activated caspase-3 and CIC-3 channel proteins. Real-time PCR was used to detect the mRNA expression of CIC-3. The results showed that SIN-1 reduced the neuronal survival rate, induced neuronal apoptosis, and promoted ClC-3 chloride channel protein and mRNA expression in the apoptotic neurons. DIDS reversed the effect of SIN-1. Our findings indicate that the increased activities of the ClC-3 chloride channel may be involved in hippocampal neuronal apoptosis induced by nitric oxide.
Collapse
Affiliation(s)
- Lijuan Xu
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
- First Hospital of Putian City, Putian 351100, Fujian Province, China
| | - Shuling Zhang
- Department of Pediatrics, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| | - Hongling Fan
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| | - Zhichao Zhong
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| | - Xi Li
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| | - Xiaoxiao Jin
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| | - Quanzhong Chang
- Department of Physiology, Zhuhai Campus of Zunyi Medical College, Zhuhai 519041, Guangdong Province, China
| |
Collapse
|