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Dulko E, Jedrusiak M, Osuru HP, Atluri N, Illendula M, Davis EM, Beenhakker MP, Lunardi N. Sleep Fragmentation, Electroencephalographic Slowing, and Circadian Disarray in a Mouse Model for Intensive Care Unit Delirium. Anesth Analg 2023; 137:209-220. [PMID: 37192134 DOI: 10.1213/ane.0000000000006524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
BACKGROUND We aimed to further validate our previously published animal model for delirium by testing the hypothesis that in aged mice, Anesthesia, Surgery and simulated ICU conditions (ASI) induce sleep fragmentation, electroencephalographic (EEG) slowing, and circadian disarray consistent with intensive care unit (ICU) patients with delirium. METHODS A total of 41 mice were used. Mice were implanted with EEG electrodes and randomized to ASI or control groups. ASI mice received laparotomy, anesthesia, and simulated ICU conditions. Controls did not receive ASI. Sleep was recorded at the end of ICU conditions, and hippocampal tissue was collected on EEG recording. Arousals, EEG dynamics, and circadian gene expression were compared with t tests. Two-way repeated measures analysis of variance (RM ANOVA) was used to assess sleep according to light. RESULTS ASI mice experienced frequent arousals (36.6 ± 3.2 vs 26.5 ± 3.4; P = .044; 95% confidence interval [CI], 0.29-19.79; difference in mean ± SEM, 10.04 ± 4.62) and EEG slowing (frontal theta ratio, 0.223 ± 0.010 vs 0.272 ± 0.019; P = .026; 95% CI, -0.091 to -0.007; difference in mean ± SEM, -0.05 ± 0.02) relative to controls. In ASI mice with low theta ratio, EEG slowing was associated with a higher percentage of quiet wakefulness (38.2 ± 3.6 vs 13.4 ± 3.8; P = .0002; 95% CI, -35.87 to -13.84; difference in mean ± SEM, -24.86 ± 5.19). ASI mice slept longer during the dark phases of the circadian cycle (nonrapid eye movement [NREM], dark phase 1 [D1]: 138.9 ± 8.1 minutes vs 79.6 ± 9.6 minutes, P = .0003, 95% CI, -95.87 to -22.69, predicted mean difference ± SE: -59.28 ± 13.89; NREM, dark phase 2 (D2): 159.3 ± 7.3 minutes vs 112.6 ± 15.5 minutes, P = .006, 95% CI, -83.25 to -10.07, mean difference ± SE, -46.66 ± 13.89; rapid eye movement (REM), D1: 20.5 ± 2.1 minutes vs 5.8 ± 0.8 minutes, P = .001, 95% CI, -24.60 to -4.71, mean difference ± SE, -14. 65 ± 3.77; REM, D2: 21.0 ± 2.2 minutes vs 10.3 ± 1.4 minutes, P = .029, 95% CI, -20.64 to -0.76, mean difference ± SE, -10.70 ± 3.77). The expression of essential circadian genes was also lower in ASI mice (basic helix-loop-helix ARNT like [BMAL1] : -1.3 fold change; circadian locomotor output cycles protein kaput [CLOCK] : -1.2). CONCLUSIONS ASI mice experienced EEG and circadian changes mimicking those of delirious ICU patients. These findings support further exploration of this mouse approach to characterize the neurobiology of delirium.
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Affiliation(s)
| | | | | | | | | | | | - Mark P Beenhakker
- Pharmacology, University of Virginia Health, Charlottesville, Virginia
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Kilianski S, Beenhakker MP. Patterns of Pathology. Epilepsy Curr 2023; 23:56-57. [PMID: 36923347 PMCID: PMC10009130 DOI: 10.1177/15357597221137212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy Madar AD, Pfammatter JA, Bordenave J, Plumley EI, Ravi S, Cowie M, Wallace EP, Hermann BP, Maganti RK, Jones MV. J Neurosci . 2021;41(46):9669-9686. doi:10.1523/JNEUROSCI.2439-20.2021 In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.
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Gancayco CA, Gerding MR, Breault DT, Beenhakker MP, Barrett PQ, Guagliardo NA. Intrinsic Adrenal TWIK-Related Acid-Sensitive TASK Channel Dysfunction Produces Spontaneous Calcium Oscillations Sufficient to Drive AngII (Angiotensin II)-Unresponsive Hyperaldosteronism. Hypertension 2022; 79:2552-2564. [PMID: 36129175 PMCID: PMC10167771 DOI: 10.1161/hypertensionaha.122.19557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Ion channel mutations in calcium regulating genes strongly associate with AngII (angiotensin II)-independent aldosterone production. Here, we used an established mouse model of in vivo aldosterone autonomy,
Cyp11b2
-driven deletion of TWIK-related acid-sensitive potassium channels (TASK-1 and TASK-3, termed zona glomerulosa [zG]-TASK-loss-of-function), and selective pharmacological TASK channel inhibition to determine whether channel dysfunction in native, electrically excitable zG cell rosette-assemblies: (1) produces spontaneous calcium oscillatory activity and (2) is sufficient to drive substantial aldosterone autonomy.
Methods:
We imaged calcium activity in adrenal slices expressing a zG-specific calcium reporter (GCaMP3), an in vitro experimental approach that preserves the native rosette assembly and removes potentially confounding extra-adrenal contributions. In parallel experiments, we measured acute aldosterone production from adrenal slice cultures.
Results:
Absent from untreated WT slices, we find that either adrenal-specific genetic deletion or acute pharmacological TASK channel inhibition produces spontaneous oscillatory bursting behavior and steroidogenic activity (2.4-fold) that are robust, sustained, and equivalent to activities evoked by 3 nM AngII in WT slices. Moreover, spontaneous activity in zG-TASK-loss-of-function slices and inhibitor-evoked activity in WT slices are unresponsive to AngII regulation over a wide range of concentrations (50 pM to 3 µM).
Conclusions:
We provide proof of principle that spontaneous activity of zG cells within classic rosette assemblies evoked solely by a change in an intrinsic, dominant resting-state conductance can be a significant source of AngII-independent aldosterone production from native tissue.
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Affiliation(s)
| | - Molly R. Gerding
- Department of Pharmacology (M.R.G., M.P.B., P.Q.B., N.A.G.), University of Virginia, Charlottesville
| | - David T. Breault
- Division of Endocrinology, Boston Children’s Hospital, MA (D.T.B.)
- Harvard Stem Cell Institute, Cambridge, MA (D.T.B.)
| | - Mark P. Beenhakker
- Department of Pharmacology (M.R.G., M.P.B., P.Q.B., N.A.G.), University of Virginia, Charlottesville
| | - Paula Q. Barrett
- Department of Pharmacology (M.R.G., M.P.B., P.Q.B., N.A.G.), University of Virginia, Charlottesville
| | - Nick A. Guagliardo
- Department of Pharmacology (M.R.G., M.P.B., P.Q.B., N.A.G.), University of Virginia, Charlottesville
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Beenhakker MP. ThalaMS: New Evidence Linking Epilepsy, Multiple Sclerosis, and the Thalamus. Epilepsy Curr 2022; 22:246-248. [PMID: 36187140 PMCID: PMC9483751 DOI: 10.1177/15357597221097592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Modulation of Pacemaker Channel Function in a Model of Thalamocortical
Hyperexcitability by Demyelination and Cytokines Chaudhary R, Albrecht S, Datunashvili M, Cerina M, Lüttjohann A, Han Y, Narayanan V,
Chetkovich DM, Ruck T, Kuhlmann T, Pape HC, Meuth SG, Zobeiri M, Budde T.
Cerebral Cortex. 2022 Jan 25;bhab491. doi:10.1093/cercor/bhab491. A consensus is yet to be reached regarding the exact prevalence of epileptic seizures
or epilepsy in multiple sclerosis (MS). In addition, the underlying pathophysiological
basis of the reciprocal interaction among neuroinflammation, demyelination, and
epilepsy remains unclear. Therefore, a better understanding of cellular and network
mechanisms linking these pathologies is needed. Cuprizone-induced general
demyelination in rodents is a valuable model for studying MS pathologies. Here, we
studied the relationship among epileptic activity, loss of myelin, and
pro-inflammatory cytokines by inducing acute, generalized demyelination in a genetic
mouse model of human absence epilepsy, C3H/HeJ mice. Both cellular and network
mechanisms were studied using in vivo and in vitro electrophysiological techniques. We
found that acute, generalized demyelination in C3H/HeJ mice resulted in a lower number
of spike-wave discharges, increased cortical theta oscillations, and reduction of slow
rhythmic intrathalamic burst activity. In addition, generalized demyelination resulted
in a significant reduction in the amplitude of the hyperpolarization-activated inward
current (Ih) in thalamic relay cells, which was accompanied by lower surface
expression of hyperpolarization-activated, cyclic nucleotide-gated channels, and the
phosphorylated form of TRIP8b (pS237-TRIP8b). We suggest that demyelination-related
changes in thalamic Ih may be one of the factors defining the prevalence of seizures
in MS.
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Salvati KA, Souza GMPR, Lu AC, Ritger ML, Guyenet P, Abbott SB, Beenhakker MP. Respiratory alkalosis provokes spike-wave discharges in seizure-prone rats. eLife 2022; 11:72898. [PMID: 34982032 PMCID: PMC8860449 DOI: 10.7554/elife.72898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 01/03/2022] [Indexed: 12/13/2022] Open
Abstract
Hyperventilation reliably provokes seizures in patients diagnosed with absence epilepsy. Despite this predictable patient response, the mechanisms that enable hyperventilation to powerfully activate absence seizure-generating circuits remain entirely unknown. By utilizing gas exchange manipulations and optogenetics in the WAG/Rij rat, an established rodent model of absence epilepsy, we demonstrate that absence seizures are highly sensitive to arterial carbon dioxide, suggesting that seizure-generating circuits are sensitive to pH. Moreover, hyperventilation consistently activated neurons within the intralaminar nuclei of the thalamus, a structure implicated in seizure generation. We show that intralaminar thalamus also contains pH-sensitive neurons. Collectively, these observations suggest that hyperventilation activates pH-sensitive neurons of the intralaminar nuclei to provoke absence seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia, Charlottesville, United States.,Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, United States
| | - Adam C Lu
- Department of Pharmacology, University of Virginia, Charlottesville, United States.,Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
| | - Matthew L Ritger
- Department of Pharmacology, University of Virginia, Charlottesville, United States.,Neuroscience Graduate Program, University of Virginia, Charlottesville, United States
| | - Patrice Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, United States
| | - Stephen B Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, United States
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia, Charlottesville, United States
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6
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Salvati KA, Ritger ML, Davoudian PA, O’Dell F, Wyskiel DR, Souza GMPR, Lu AC, Perez-Reyes E, Drake JC, Yan Z, Beenhakker MP. OUP accepted manuscript. Brain 2022; 145:2332-2346. [PMID: 35134125 PMCID: PMC9337815 DOI: 10.1093/brain/awac037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 12/20/2021] [Accepted: 12/26/2021] [Indexed: 11/21/2022] Open
Abstract
Metabolism regulates neuronal activity and modulates the occurrence of epileptic seizures. Here, using two rodent models of absence epilepsy, we show that hypoglycaemia increases the occurrence of spike-wave seizures. We then show that selectively disrupting glycolysis in the thalamus, a structure implicated in absence epilepsy, is sufficient to increase spike-wave seizures. We propose that activation of thalamic AMP-activated protein kinase, a sensor of cellular energetic stress and potentiator of metabotropic GABAB-receptor function, is a significant driver of hypoglycaemia-induced spike-wave seizures. We show that AMP-activated protein kinase augments postsynaptic GABAB-receptor-mediated currents in thalamocortical neurons and strengthens epileptiform network activity evoked in thalamic brain slices. Selective thalamic AMP-activated protein kinase activation also increases spike-wave seizures. Finally, systemic administration of metformin, an AMP-activated protein kinase agonist and common diabetes treatment, profoundly increased spike-wave seizures. These results advance the decades-old observation that glucose metabolism regulates thalamocortical circuit excitability by demonstrating that AMP-activated protein kinase and GABAB-receptor cooperativity is sufficient to provoke spike-wave seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Epilepsy Research Laboratory and Weil Institute for Neurosciences, Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Matthew L Ritger
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Pasha A Davoudian
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- MD-PhD Program, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Finnegan O’Dell
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Daniel R Wyskiel
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Adam C Lu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joshua C Drake
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- The Robert M. Berne Center for Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Zhen Yan
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- The Robert M. Berne Center for Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mark P Beenhakker
- Correspondence to: Mark P. Beenhakker Department of Pharmacology University of Virginia School of Medicine Charlottesville, VA, 22908, USA E-mail:
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7
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Salvati KA, Mason AJ, Gailey CD, Wang EJ, Fu Z, Beenhakker MP. Mice Harboring a Non-Functional CILK1/ICK Allele Fail to Model the Epileptic Phenotype in Patients Carrying Variant CILK1/ICK. Int J Mol Sci 2021; 22:ijms22168875. [PMID: 34445580 PMCID: PMC8396347 DOI: 10.3390/ijms22168875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/15/2021] [Accepted: 08/15/2021] [Indexed: 11/16/2022] Open
Abstract
CILK1 (ciliogenesis associated kinase 1)/ICK (intestinal cell kinase) is a highly conserved protein kinase that regulates primary cilia structure and function. CILK1 mutations cause a wide spectrum of human diseases collectively called ciliopathies. While several CILK1 heterozygous variants have been recently linked to juvenile myoclonic epilepsy (JME), it remains unclear whether these mutations cause seizures. Herein, we investigated whether mice harboring either a heterozygous null Cilk1 (Cilk1+/−) mutation or a heterozygous loss-of-function Cilk1 mutation (Cilk1R272Q/+) have epilepsy. We first evaluated the spontaneous seizure phenotype of Cilk1+/− and Cilk1R272Q/+ mice relative to wildtype littermates. We observed no electrographic differences among the three mouse genotypes during prolonged recordings. We also evaluated electrographic and behavioral responses of mice recovering from isoflurane anesthesia, an approach recently used to measure seizure-like activity. Again, we observed no electrographic or behavioral differences in control versus Cilk1+/− and Cilk1R272Q/+ mice upon isoflurane recovery. These results indicate that mice bearing a non-functional copy of Cilk1 fail to produce electrographic patterns resembling those of JME patients with a variant CILK1 copy. Our findings argue against CILK1 haploinsufficiency being the mechanism that links CILK1 variants to JME.
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Affiliation(s)
- Kathryn A. Salvati
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
- Department of Neurological Surgery and Weill Institute for Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Ashley J. Mason
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
| | - Casey D. Gailey
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
| | - Eric J. Wang
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
| | - Zheng Fu
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
- UVA Cancer Center, Cancer Biology Program, University of Virginia, Charlottesville, VA 22908, USA
- Correspondence: (Z.F.); (M.P.B.)
| | - Mark P. Beenhakker
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; (K.A.S.); (A.J.M.); (C.D.G.); (E.J.W.)
- UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA
- Correspondence: (Z.F.); (M.P.B.)
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Salvati KA, Beenhakker MP. Lost in Space: How a Single, Directionless Protein Can Cause So Much Mayhem. Epilepsy Curr 2021; 20:381-383. [PMID: 34025260 PMCID: PMC7818206 DOI: 10.1177/1535759720955169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
An Epilepsy-Associated SV2A Mutation Disrupts Synaptotagmin-1 Expression and
Activity-Dependent Trafficking Harper CB, Small C, Davenport EC, Davenport EC, Low DW, Smillie KJ, Martínez-Mármol
R, Meunier FA, Cousin MA. J Neurosci. 2020;40(23):4586-4595. doi:
10.1523/JNEUROSCI.0210-20.2020 The epilepsy-linked gene SV2A has a number of potential roles in the synaptic vesicle
(SV) life cycle. However, how loss of SV2A function translates into presynaptic
dysfunction and ultimately seizure activity is still undetermined. In this study, we
examined whether the first SV2A mutation identified in human disease (R383Q) could
provide information, regarding which SV2A-dependent events are critical in the
translation to epilepsy. We utilized a molecular replacement strategy in which
exogenous SV2A was expressed in mouse neuronal cultures of either sex, which had been
depleted of endogenous SV2A to mimic the homozygous human condition. We found that the
R383Q mutation resulted in a mislocalization of SV2A from SVs to the plasma membrane
but had no effect on its activity-dependent trafficking. This SV2A mutant displayed
reduced mobility when stranded on the plasma membrane and reduced binding to its
interaction partner synaptotagmin-1 (Syt1). Furthermore, the R383Q mutant failed to
rescue reduced expression and dysfunctional activity-dependent trafficking of Syt1 in
the absence of endogenous SV2A. This suggests that the inability to control Syt1
expression and trafficking at the presynapse may be key in the transition from loss of
SV2A function to seizure activity.
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Lu AC, Lee CK, Kleiman-Weiner M, Truong B, Wang M, Huguenard JR, Beenhakker MP. Nonlinearities between inhibition and T-type calcium channel activity bidirectionally regulate thalamic oscillations. eLife 2020; 9:e59548. [PMID: 32902384 PMCID: PMC7529462 DOI: 10.7554/elife.59548] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022] Open
Abstract
Absence seizures result from 3 to 5 Hz generalized thalamocortical oscillations that depend on highly regulated inhibitory neurotransmission in the thalamus. Efficient reuptake of the inhibitory neurotransmitter GABA is essential, and reuptake failure worsens human seizures. Here, we show that blocking GABA transporters (GATs) in acute rat brain slices containing key parts of the thalamocortical seizure network modulates epileptiform activity. As expected, we found that blocking either GAT1 or GAT3 prolonged oscillations. However, blocking both GATs unexpectedly suppressed oscillations. Integrating experimental observations into single-neuron and network-level computational models shows how a non-linear dependence of T-type calcium channel gating on GABAB receptor activity regulates network oscillations. Receptor activity that is either too brief or too protracted fails to sufficiently open T-type channels necessary for sustaining oscillations. Only within a narrow range does prolonging GABAB receptor activity promote channel opening and intensify oscillations. These results have implications for therapeutics that modulate inhibition kinetics.
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Affiliation(s)
- Adam C Lu
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | | | | | - Brian Truong
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Megan Wang
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - John R Huguenard
- Department of Neurology, Stanford UniversityPalo AltoUnited States
| | - Mark P Beenhakker
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
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Guagliardo NA, Klein PM, Gancayco CA, Lu A, Leng S, Makarem RR, Cho C, Rusin CG, Breault DT, Barrett PQ, Beenhakker MP. Angiotensin II induces coordinated calcium bursts in aldosterone-producing adrenal rosettes. Nat Commun 2020; 11:1679. [PMID: 32245948 PMCID: PMC7125102 DOI: 10.1038/s41467-020-15408-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 02/28/2020] [Indexed: 12/15/2022] Open
Abstract
Aldosterone-producing zona glomerulosa (zG) cells of the adrenal gland arrange in distinct multi-cellular rosettes that provide a structural framework for adrenal cortex morphogenesis and plasticity. Whether this cyto-architecture also plays functional roles in signaling remains unexplored. To determine if structure informs function, we generated mice with zG-specific expression of GCaMP3 and imaged zG cells within their native rosette structure. Here we demonstrate that within the rosette, angiotensin II evokes periodic Cav3-dependent calcium events that form bursts that are stereotypic in form. Our data reveal a critical role for angiotensin II in regulating burst occurrence, and a multifunctional role for the rosette structure in activity-prolongation and coordination. Combined our data define the calcium burst as the fundamental unit of zG layer activity evoked by angiotensin II and highlight a novel role for the rosette as a facilitator of cell communication.
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Affiliation(s)
| | - Peter M Klein
- Departments of Pharmacology, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | | | - Adam Lu
- Departments of Pharmacology, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | - Sining Leng
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, USA
| | | | - Chelsea Cho
- Departments of Pharmacology, Charlottesville, VA, USA
| | - Craig G Rusin
- Department of Pediatrics-Cardiology, Baylor College of Medicine, and Harvard Stem Cell Institute, Cambridge, MA, USA
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, USA
| | | | - Mark P Beenhakker
- Departments of Pharmacology, Charlottesville, VA, USA.
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA.
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Abstract
Whole-Brain Neuronal Activity Displays Crackling Noise Dynamics Ponce-Alvarez A, Jouary A, Privat M, Deco G, Sumbre G. Neuron. 2018;100(6):1446-1459.e6. doi:10.1016/j.neuron.2018.10.045 Previous studies suggest that the brain operates at a critical point in which phases of order and disorder coexist, producing emergent patterned dynamics at all scales and optimizing several brain functions. Here, we combined light-sheet microscopy with GCaMP zebrafish larvae to study whole-brain dynamics in vivo at near single-cell resolution. We show that spontaneous activity propagates in the brain’s 3-dimensional space, generating scale-invariant neuronal avalanches with time courses and recurrence times that exhibit statistical self-similarity at different magnitude, temporal, and frequency scales. This suggests that the nervous system operates close to a nonequilibrium phase transition, where a large repertoire of spatial, temporal, and interactive modes can be supported. Finally, we show that gap junctions contribute to the maintenance of criticality and that, during interactions with the environment (sensory inputs and self-generated behaviors), the system is transiently displaced to a more ordered regime, conceivably to limit the potential sensory representations and motor outcomes.
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12
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Newmyer BA, Whindleton CM, Klein PM, Beenhakker MP, Jones MK, Scott MM. VIPergic neurons of the infralimbic and prelimbic cortices control palatable food intake through separate cognitive pathways. JCI Insight 2019; 5:126283. [PMID: 30939126 PMCID: PMC6538359 DOI: 10.1172/jci.insight.126283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/27/2019] [Indexed: 11/17/2022] Open
Abstract
The prefrontal cortex controls food reward seeking and ingestion, playing important roles in directing attention, regulating motivation towards reward pursuit, and the assignment of reward salience and value. The cell types that mediate these behavioral functions, however, are not well described. We report here that optogenetic activation of vasoactive peptide expressing (VIP) interneurons in both the infralimbic (IL) and prelimbic (PL) divisions of the medial prefrontal cortex in mice is sufficient to reduce acute, binge-like intake of high calorie palatable food in the absence of any effect on low calorie rodent chow intake in the sated animal. In addition, we discovered that the behavioral mechanisms associated with these changes in feeding differed between animals that underwent either IL or PL VIPergic stimulation. While IL VIP neurons showed the ability to reduce palatable food intake, this effect was dependent upon the novelty and relative value of the food source. In addition, IL VIP neuron activation significantly reduced novel object- and novel social investigative behavior. Activation of PL VIP neurons, however, produced a reduction in high calorie palatable food intake that was independent of food novelty. Neither IL nor PL VIP excitation changed motivation to obtain food reward. Our data show how neurochemically-defined populations of cortical interneurons can regulate specific aspects of food reward-driven behavior, resulting in a selective reduction in intake of highly valued food.
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Affiliation(s)
| | | | | | | | - Marieke K. Jones
- Health Sciences Library, University of Virginia, Charlottesville, Virginia, USA
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13
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Joksimovic SM, Osuru HP, Oklopcic A, Beenhakker MP, Jevtovic-Todorovic V, Todorovic SM. Histone Deacetylase Inhibitor Entinostat (MS-275) Restores Anesthesia-induced Alteration of Inhibitory Synaptic Transmission in the Developing Rat Hippocampus. Mol Neurobiol 2019; 55:222-228. [PMID: 28840475 DOI: 10.1007/s12035-017-0735-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent evidence strongly supports the idea that common general anesthetics (GAs) such as isoflurane (Iso) and nitrous oxide (N2O; laughing gas), as well as sedative drugs such as midazolam are neurotoxic for the developing mammalian brain having deleterious effects on neural circuits involved in cognition, learning and memory. However, to date, very little is known about epigenetic mechanisms involved in GA-induced plasticity of synaptic transmission in the hippocampus, the main memory-processing region in the brain. Here, we used patch-clamp recordings of miniature inhibitory post-synaptic currents (mIPSCs) from hippocampal neurons in slice cultures exposed to the clinically relevant GA combination. We found that in vitro exposure to a combination of midazolam, 0.75% Iso, and 70% N2O for 6 h leads to lasting increase in frequency of mIPSCs, while amplitudes and kinetics of the events were spared. Importantly, co-application of entinostat (MS-275), a selective inhibitor of class I histone deacetylases (HDAC), completely reversed GA-induced synaptic plasticity. Furthermore, when given in vivo to P7 pups exposed to GA with midazolam, Iso and N2O for 6 h, MS-275 reversed GA-induced histone-3 hypoacetylation as shown by an increase in Ac-H3 protein expression in the hippocampus. We conclude that exposure to a combination of Iso with N2O and midazolam causes plasticity of mIPSCs in hippocampal neurons by epigenetic mechanisms that target presynaptic sites. We hypothesize that GA-induced epigenetic alterations in inhibitory synaptic transmission in the hippocampus may contribute to altered neuronal excitability and consequently abnormal learning and memory later in life.
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Affiliation(s)
- Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Hari Prasad Osuru
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Azra Oklopcic
- Clinical Trial Office, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA. .,Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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14
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Harbom LJ, Rudisill TL, Michel N, Litwa KA, Beenhakker MP, McConnell MJ. The effect of rho kinase inhibition on morphological and electrophysiological maturity in iPSC-derived neurons. Cell Tissue Res 2018; 375:641-654. [PMID: 30406823 DOI: 10.1007/s00441-018-2942-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/05/2018] [Indexed: 02/07/2023]
Abstract
Induced pluripotent stem cell (iPSC)-derived neurons permit the study of neurogenesis and neurological disease in a human setting. However, the electrophysiological properties of iPSC-derived neurons are consistent with those observed in immature cortical neurons, including a high membrane resistance depolarized resting membrane potential and immature firing properties, limiting their use in modeling neuronal activity in adult cells. Based on the proven association between inhibiting rho kinase (ROCK) and increased neurite complexity, we seek to determine if short-term ROCK inhibition during the first 1-2 weeks of differentiation would increase morphological complexity and electrophysiological maturity after several weeks of differentiation. While inhibiting ROCK resulted in increased neurite formation after 24 h, this effect did not persist at 3 and 6 weeks of age. Additionally, there was no effect of ROCK inhibition on electrophysiological properties at 2-3, 6, or 12 weeks of age, despite an increase in evoked and spontaneous firing and a more hyperpolarized resting membrane potential over time. These results indicate that while there is a clear effect of time on electrophysiological maturity, ROCK inhibition did not accelerate maturity.
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Affiliation(s)
- Lise J Harbom
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Department of Biochemistry and Molecular Genetics and Neuroscience, Centers for Brain Immunology and Glia, Public Health Genomics, and Children's Health Research, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Neuroscience Graduate Program, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Taylor L Rudisill
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Nadine Michel
- Department of Biochemistry and Molecular Genetics and Neuroscience, Centers for Brain Immunology and Glia, Public Health Genomics, and Children's Health Research, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Neuroscience Graduate Program, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Karen A Litwa
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.
| | - Michael J McConnell
- Department of Biochemistry and Molecular Genetics and Neuroscience, Centers for Brain Immunology and Glia, Public Health Genomics, and Children's Health Research, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.
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15
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Klein PM, Lu AC, Harper ME, McKown HM, Morgan JD, Beenhakker MP. Tenuous Inhibitory GABAergic Signaling in the Reticular Thalamus. J Neurosci 2018; 38:1232-1248. [PMID: 29273603 PMCID: PMC5792478 DOI: 10.1523/jneurosci.1345-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/20/2017] [Accepted: 11/03/2017] [Indexed: 11/21/2022] Open
Abstract
Maintenance of a low intracellular Cl- concentration ([Cl-]i) is critical for enabling inhibitory neuronal responses to GABAA receptor-mediated signaling. Cl- transporters, including KCC2, and extracellular impermeant anions ([A]o) of the extracellular matrix are both proposed to be important regulators of [Cl-]i Neurons of the reticular thalamic (RT) nucleus express reduced levels of KCC2, indicating that GABAergic signaling may produce excitation in RT neurons. However, by performing perforated patch recordings and calcium imaging experiments in rats (male and female), we find that [Cl-]i remains relatively low in RT neurons. Although we identify a small contribution of [A]o to a low [Cl-]i in RT neurons, our results also demonstrate that reduced levels of KCC2 remain sufficient to maintain low levels of Cl- Reduced KCC2 levels, however, restrict the capacity of RT neurons to rapidly extrude Cl- following periods of elevated GABAergic signaling. In a computational model of a local RT network featuring slow Cl- extrusion kinetics, similar to those we found experimentally, model RT neurons are predisposed to an activity-dependent switch from GABA-mediated inhibition to excitation. By decreasing the activity threshold required to produce excitatory GABAergic signaling, weaker stimuli are able to propagate activity within the model RT nucleus. Our results indicate the importance of even diminished levels of KCC2 in maintaining inhibitory signaling within the RT nucleus and suggest how this important activity choke point may be easily overcome in disorders such as epilepsy.SIGNIFICANCE STATEMENT Precise regulation of intracellular Cl- levels ([Cl-]i) preserves appropriate, often inhibitory, GABAergic signaling within the brain. However, there is disagreement over the relative contribution of various mechanisms that maintain low [Cl-]i We found that the Cl- transporter KCC2 is an important Cl- extruder in the reticular thalamic (RT) nucleus, despite this nucleus having remarkably low KCC2 immunoreactivity relative to other regions of the adult brain. We also identified a smaller contribution of fixed, impermeant anions ([A]o) to lowering [Cl-]i in RT neurons. Inhibitory signaling among RT neurons is important for preventing excessive activation of RT neurons, which can be responsible for generating seizures. Our work suggests that KCC2 critically restricts the spread of activity within the RT nucleus.
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Affiliation(s)
- Peter M Klein
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Adam C Lu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Megan E Harper
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Hannah M McKown
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Jessica D Morgan
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
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16
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Abstract
Voluntary hyperventilation triggers seizures in the vast majority of people with absence epilepsy. The mechanisms that underlie this phenomenon remain unknown. Herein, we review observations - many made long ago - that provide insight into the relationship between breathing and absence seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States.
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17
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Filiano AJ, Xu Y, Tustison NJ, Marsh RL, Baker W, Smirnov I, Overall CC, Gadani SP, Turner SD, Weng Z, Peerzade SN, Chen H, Lee KS, Scott MM, Beenhakker MP, Litvak V, Kipnis J. Unexpected role of interferon-γ in regulating neuronal connectivity and social behaviour. Nature 2016; 535:425-9. [PMID: 27409813 PMCID: PMC4961620 DOI: 10.1038/nature18626] [Citation(s) in RCA: 442] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 06/03/2016] [Indexed: 12/31/2022]
Abstract
Immune dysfunction is commonly associated with several neurological and mental disorders. Although the mechanisms by which peripheral immunity may influence neuronal function are largely unknown, recent findings implicate meningeal immunity influencing behavior, such as spatial learning and memory1. Here we show that meningeal immunity is also critical for social behavior; mice deficient in adaptive immunity exhibit social deficits and hyper-connectivity of fronto-cortical brain regions. Associations between rodent transcriptomes from brain and cellular transcriptomes in response to T cell–derived cytokines suggest a strong interaction between social behavior and interferon-gamma (IFN-γ) driven responses. Concordantly, we demonstrate that inhibitory neurons respond to IFN-γ and increase GABAergic currents in projection neurons, suggesting that IFN-γ is a molecular link between meningeal immunity and neural circuits recruited for social behavior. Meta-analysis on the transcriptomes of a range of organisms revealed that rodents, fish, and flies elevate IFN-γ/JAK-STAT–dependent gene signatures in a social context, suggesting that the IFN-γ signaling pathway could mediate a co-evolutionary link between social/aggregation behavior and an efficient anti-pathogen response. This study implicates adaptive immune dysfunction, in particular IFN-γ, in disorders characterized by social dysfunction and suggests a co-evolutionary link between social behavior and an anti-pathogen immune response driven by IFN-γ signaling.
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18
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Barrett PQ, Guagliardo NA, Klein PM, Hu C, Breault DT, Beenhakker MP. Role of voltage-gated calcium channels in the regulation of aldosterone production from zona glomerulosa cells of the adrenal cortex. J Physiol 2016; 594:5851-5860. [PMID: 26845064 DOI: 10.1113/jp271896] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 11/28/2015] [Indexed: 11/08/2022] Open
Abstract
Zona glomerulosa cells (ZG) of the adrenal gland constantly integrate fluctuating ionic, hormonal and paracrine signals to control the synthesis and secretion of aldosterone. These signals modulate Ca2+ levels, which provide the critical second messenger to drive steroid hormone production. Angiotensin II is a hormone known to modulate the activity of voltage-dependent L- and T-type Ca2+ channels that are expressed on the plasma membrane of ZG cells in many species. Because the ZG cell maintains a resting membrane voltage of approximately -85 mV and has been considered electrically silent, low voltage-activated T-type Ca2+ channels are assumed to provide the primary Ca2+ signal that drives aldosterone production. However, this view has recently been challenged by human genetic studies identifying somatic gain-of-function mutations in L-type CaV 1.3 channels in aldosterone-producing adenomas of patients with primary hyperaldosteronism. We provide a review of these assumptions and challenges, and update our understanding of the state of the ZG cell in a layer in which native cellular associations are preserved. This updated view of Ca2+ signalling in ZG cells provides a unifying mechanism that explains how transiently activating CaV 3.2 channels can generate a significant and recurring Ca2+ signal, and how CaV 1.3 channels may contribute to the Ca2+ signal that drives aldosterone production.
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Affiliation(s)
- Paula Q Barrett
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22947, USA
| | - Nick A Guagliardo
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22947, USA
| | - Peter M Klein
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22947, USA
| | - Changlong Hu
- Department of Physiology and Biophysics, School of Life Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200433, China
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22947, USA.
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19
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Wang G, Bochorishvili G, Chen Y, Salvati KA, Zhang P, Dubel SJ, Perez-Reyes E, Snutch TP, Stornetta RL, Deisseroth K, Erisir A, Todorovic SM, Luo JH, Kapur J, Beenhakker MP, Zhu JJ. CaV3.2 calcium channels control NMDA receptor-mediated transmission: a new mechanism for absence epilepsy. Genes Dev 2015. [PMID: 26220996 PMCID: PMC4526737 DOI: 10.1101/gad.260869.115] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CaV3.2 T-type calcium channels, encoded by CACNA1H, are expressed throughout the brain, yet their general function remains unclear. We discovered that CaV3.2 channels control NMDA-sensitive glutamatergic receptor (NMDA-R)-mediated transmission and subsequent NMDA-R-dependent plasticity of AMPA-R-mediated transmission at rat central synapses. Interestingly, functional CaV3.2 channels primarily incorporate into synapses, replace existing CaV3.2 channels, and can induce local calcium influx to control NMDA transmission strength in an activity-dependent manner. Moreover, human childhood absence epilepsy (CAE)-linked hCaV3.2(C456S) mutant channels have a higher channel open probability, induce more calcium influx, and enhance glutamatergic transmission. Remarkably, cortical expression of hCaV3.2(C456S) channels in rats induces 2- to 4-Hz spike and wave discharges and absence-like epilepsy characteristic of CAE patients, which can be suppressed by AMPA-R and NMDA-R antagonists but not T-type calcium channel antagonists. These results reveal an unexpected role of CaV3.2 channels in regulating NMDA-R-mediated transmission and a novel epileptogenic mechanism for human CAE.
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Affiliation(s)
- Guangfu Wang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Genrieta Bochorishvili
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yucai Chen
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kathryn A Salvati
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Peng Zhang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Steve J Dubel
- Laboratoire de Génomique Fonctionnelle, Département de Physiologie, Unité Propre de Recherche 2580, Centre National de la Recherche Scientifique, 34396 Montpellier, France
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Terrance P Snutch
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, California 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Virginia, Charlottesville, Virginia 22908, USA; Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jian-Hong Luo
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - J Julius Zhu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA; Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, USA
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20
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Lee AJ, Wang G, Jiang X, Johnson SM, Hoang ET, Lanté F, Stornetta RL, Beenhakker MP, Shen Y, Julius Zhu J. Canonical Organization of Layer 1 Neuron-Led Cortical Inhibitory and Disinhibitory Interneuronal Circuits. Cereb Cortex 2014; 25:2114-26. [PMID: 24554728 DOI: 10.1093/cercor/bhu020] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Interneurons play a key role in cortical function and dysfunction, yet organization of cortical interneuronal circuitry remains poorly understood. Cortical Layer 1 (L1) contains 2 general GABAergic interneuron groups, namely single bouquet cells (SBCs) and elongated neurogliaform cells (ENGCs). SBCs predominantly make unidirectional inhibitory connections (SBC→) with L2/3 interneurons, whereas ENGCs frequently form reciprocal inhibitory and electric connections (ENGC↔) with L2/3 interneurons. Here, we describe a systematic investigation of the pyramidal neuron targets of L1 neuron-led interneuronal circuits in the rat barrel cortex with simultaneous octuple whole-cell recordings and report a simple organizational scheme of the interneuronal circuits. Both SBCs→ and ENGC ↔ L2/3 interneuronal circuits connect to L2/3 and L5, but not L6, pyramidal neurons. SBC → L2/3 interneuronal circuits primarily inhibit the entire dendritic-somato-axonal axis of a few L2/3 and L5 pyramidal neurons located within the same column. In contrast, ENGC ↔ L2/3 interneuronal circuits generally inhibit the distal apical dendrite of many L2/3 and L5 pyramidal neurons across multiple columns. Finally, L1 interneuron-led circuits target distinct subcellular compartments of L2/3 and L5 pyramidal neurons in a L2/3 interneuron type-dependent manner. These results suggest that L1 neurons form canonical interneuronal circuits to control information processes in both supra- and infragranular cortical layers.
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Affiliation(s)
- Alice J Lee
- Department of Pharmacology Department of Biology
| | | | | | | | - Elizabeth T Hoang
- Department of Pharmacology Department of Psychology, School of Medicine and College of Arts and Sciences, University of Virginia, Charlottesville, VA 22908, USA
| | | | | | | | - Ying Shen
- Department of Neurobiology and Key Laboratory of Medical Neurobiology of Chinese Ministry of Health, Zhejiang University School of Medicine, 388 Yu Hang Tang Road, Hangzhou 310058, PR China
| | - J Julius Zhu
- Department of Pharmacology Department of Neuroscience
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21
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DeLong ND, Beenhakker MP, Nusbaum MP. Presynaptic inhibition selectively weakens peptidergic cotransmission in a small motor system. J Neurophysiol 2009; 102:3492-504. [PMID: 19828722 DOI: 10.1152/jn.00833.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The presence and influence of neurons containing multiple neurotransmitters is well established, including the ability of coreleased transmitters to influence the same or different postsynaptic targets. Little is known, however, regarding whether presynaptic regulation of multitransmitter neurons influences all transmission from these neurons. Using the identified neurons and motor networks in the crab stomatogastric ganglion, we document the ability of presynaptic inhibition to selectively inhibit peptidergic cotransmission. Specifically, we determine that the gastropyloric receptor (GPR) proprioceptor neuron uses presynaptic inhibition to selectively regulate peptidergic cotransmission from the axon terminals of MCN1, a projection neuron that drives the biphasic (retraction, protraction) gastric mill (chewing) rhythm. MCN1 drives this rhythm via fast GABAergic excitation of the retraction neuron Int1 and slow peptidergic excitation of the lateral gastric (LG) protraction neuron. We first demonstrate that GPR inhibition of the MCN1 axon terminals is serotonergic and then establish that this serotonergic inhibition weakens MCN1 peptidergic excitation of LG without altering MCN1 GABAergic excitation of Int1. At the circuit level, we show that this selective regulation of MCN1 peptidergic cotransmission is necessary for the normal GPR regulation of the gastric mill rhythm. This is the first demonstration, at the level of individual identified neurons, that a presynaptic input can selectively regulate a subset of coreleased transmitters. This selective regulation changes the balance of cotransmitter actions by the target multitransmitter neuron, thereby enabling this neuron to have state-dependent actions on its target network. This finding reveals additional flexibility afforded by the ability of neurons to corelease multiple neurotransmitters.
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Affiliation(s)
- Nicholas D DeLong
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6074, USA
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22
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Bryant AS, Li B, Beenhakker MP, Huguenard JR. Maintenance of thalamic epileptiform activity depends on the astrocytic glutamate-glutamine cycle. J Neurophysiol 2009; 102:2880-8. [PMID: 19741104 DOI: 10.1152/jn.00476.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The generation of prolonged neuronal activity depends on the maintenance of synaptic neurotransmitter pools. The astrocytic glutamate-glutamine cycle is a major mechanism for recycling the neurotransmitters GABA and glutamate. Here we tested the effect of disrupting the glutamate-glutamine cycle on two types of neuronal activity patterns in the thalamus: sleep-related spindles and epileptiform oscillations. In recording conditions believed to induce glutamine scarcity, epileptiform oscillations showed a progressive reduction in duration that was partially reversible by the application of exogenous glutamine (300 muM). Blocking uptake of glutamine into neurons with alpha-(methylamino) isobutyric acid (5 mM) caused a similar reduction in oscillation duration, as did blocking neuronal GABA synthesis with 3-mercaptoproprionic acid (10 muM). However, comparable manipulations did not affect sleep spindles. Together, these results support a crucial role for the glutamate-glutamine cycle in providing the neurotransmitters necessary for the generation of epileptiform activity and suggest potential therapeutic approaches that selectively reduce seizure activity but maintain normal neuronal activity.
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Affiliation(s)
- Astra S Bryant
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305-5122, USA
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23
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Beenhakker MP, Huguenard JR. Neurons that fire together also conspire together: is normal sleep circuitry hijacked to generate epilepsy? Neuron 2009; 62:612-32. [PMID: 19524522 PMCID: PMC2748990 DOI: 10.1016/j.neuron.2009.05.015] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 02/02/2023]
Abstract
Brain circuits oscillate during sleep. The same circuits appear to generate pathological oscillations. In this review, we discuss recent advances in our understanding of how epilepsy co-opts normal, sleep-related circuits to generate seizures.
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Affiliation(s)
- Mark P Beenhakker
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford University, Stanford, CA 94305, USA
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24
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Kleiman-Weiner M, Beenhakker MP, Segal WA, Huguenard JR. Synergistic roles of GABAA receptors and SK channels in regulating thalamocortical oscillations. J Neurophysiol 2009; 102:203-13. [PMID: 19386752 DOI: 10.1152/jn.91158.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rhythmic oscillations throughout the cortex are observed during physiological and pathological states of the brain. The thalamus generates sleep spindle oscillations and spike-wave discharges characteristic of absence epilepsy. Much has been learned regarding the mechanisms underlying these oscillations from in vitro brain slice preparations. One widely used model to understand the epileptiform oscillations underlying absence epilepsy involves application of bicuculline methiodide (BMI) to brain slices containing the thalamus. BMI is a well-known GABAA receptor blocker that has previously been discovered to also block small-conductance, calcium-activated potassium (SK) channels. Here we report that the robust epileptiform oscillations observed during BMI application rely synergistically on both GABAA receptor and SK channel antagonism. Neither application of picrotoxin, a selective GABAA receptor antagonist, nor application of apamin, a selective SK channel antagonist, alone yielded the highly synchronized, long-lasting oscillations comparable to those observed during BMI application. However, partial blockade of SK channels by subnanomolar concentrations of apamin combined with picrotoxin sufficiently replicated BMI oscillations. We found that, at the cellular level, apamin enhanced the intrinsic excitability of reticular nucleus (RT) neurons but had no effect on relay neurons. This work suggests that regulation of RT excitability by SK channels can influence the excitability of thalamocortical networks and may illuminate possible pharmacological treatments for absence epilepsy. Finally, our results suggest that changes in the intrinsic properties of individual neurons and changes at the circuit level can robustly modulate these oscillations.
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Affiliation(s)
- Max Kleiman-Weiner
- Department of Biological Sciences, Rm. M030 Alway Bldg., Stanford University, School of Medicine, Stanford, CA 94305-5122, USA
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Beenhakker MP, DeLong ND, Saideman SR, Nadim F, Nusbaum MP. Proprioceptor regulation of motor circuit activity by presynaptic inhibition of a modulatory projection neuron. J Neurosci 2006; 25:8794-806. [PMID: 16177049 PMCID: PMC6510986 DOI: 10.1523/jneurosci.2663-05.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Phasically active sensory systems commonly influence rhythmic motor activity via synaptic actions on the relevant circuit and/or motor neurons. Using the crab stomatogastric nervous system (STNS), we identified a distinct synaptic action by which an identified proprioceptor, the gastropyloric muscle stretch receptor (GPR) neuron, regulates the gastric mill (chewing) motor rhythm. Previous work showed that rhythmically stimulating GPR in a gastric mill-like pattern, in the isolated STNS, elicits the gastric mill rhythm via its activation of two identified projection neurons, modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2, in the commissural ganglia. Here, we determine how activation of GPR with a behaviorally appropriate pattern (active during each gastric mill retractor phase) influences an ongoing gastric mill rhythm via actions in the stomato gastric ganglion, where the gastric mill circuit is located. Stimulating GPR during each retractor phase selectively prolongs that phase and thereby slows the ongoing rhythm. This selective action on the retractor phase results from two distinct GPR actions. First, GPR presynaptically inhibits the axon terminals of MCN1, reducing MCN1 excitation of all gastric mill neurons. Second, GPR directly excites the retractor phase neurons. Because MCN1 transmitter release occurs during each retractor phase, these parallel GPR actions selectively reduce the buildup of excitatory drive to the protractor phase neurons, delaying each protractor burst. Thus, rhythmic proprioceptor feedback to a motor circuit can result from a global reduction in excitatory drive to that circuit, via presynaptic inhibition, coupled with a phase-specific excitatory input that prolongs the excited phase by delaying the onset of the subsequent phase.
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Affiliation(s)
- Mark P Beenhakker
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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26
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Abstract
Individual neuronal circuits can generate multiple activity patterns because of the influence of different projection neurons. However, in most systems it has been difficult to identify and assess the relative contribution of all upstream neurons responsible for the activation of any single activity pattern by a behaviorally relevant stimulus. To elucidate this issue, we used the stomatogastric nervous system (STNS) of the crab. The STNS includes the gastric mill (chewing) motor circuit in the stomatogastric ganglion (STG) and no more than 20 projection neurons that innervate the STG. We previously identified at least some (four) of the projection neurons that are activated directly by the ventral cardiac neuron (VCN) system, a population of mechanosensory neurons that activates the gastric mill circuit. Here we show that two of these projection neurons, the previously identified modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2 (CPN2), are necessary and likely sufficient for the initiation/maintenance of the VCN-elicited gastric mill rhythm. Selective inactivation of either MCN1 or CPN2 still enabled a VCN-elicited gastric mill rhythm. However, because MCN1 and CPN2 have different actions on gastric mill neurons, these manipulations resulted in rhythms distinct from each other and from that occurring in the intact system. After removal of both MCN1 and CPN2, VCN stimulation failed to activate the gastric mill rhythm. Selective conjoint stimulation of MCN1 and CPN2, approximating their VCN-elicited activity patterns and firing frequencies, elicited a VCN-like gastric mill rhythm. Thus the VCN mechanosensory system elicits the gastric mill rhythm via its activation of a subset of the relevant projection neurons.
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Affiliation(s)
- Mark P Beenhakker
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA
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27
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Blitz DM, Beenhakker MP, Nusbaum MP. Different sensory systems share projection neurons but elicit distinct motor patterns. J Neurosci 2004; 24:11381-90. [PMID: 15601944 PMCID: PMC6494448 DOI: 10.1523/jneurosci.3219-04.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/08/2004] [Accepted: 11/08/2004] [Indexed: 11/21/2022] Open
Abstract
Considerable research has focused on issues pertaining to sensorimotor integration, but in most systems precise information remains unavailable regarding the specific pathways by which different sensory systems regulate any single central pattern-generating circuit. We address this issue by determining how two muscle stretch-sensitive neurons, the gastropyloric receptor neurons (GPRs), influence identified projection neurons that regulate the gastric mill circuit in the stomatogastric nervous system of the crab and then comparing these actions with those of the ventral cardiac neuron (VCN) mechanosensory system. Here, we show that the GPR neurons activate the gastric mill rhythm in the stomatogastric ganglion (STG) via their excitation of two identified projection neurons, modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2 (CPN2), in the commissural ganglion. Support for this conclusion comes from the ability of the modulatory proctolin neuron (MPN), a projection neuron that suppresses the gastric mill rhythm via its inhibitory actions on MCN1 and CPN2, to inhibit the GPR-elicited gastric mill rhythm. Selective elimination of MCN1 and CPN2 access to the STG also prevents GPR activation of this rhythm. The VCN neurons also elicit the gastric mill rhythm by coactivating MCN1 and CPN2, but the GPR-elicited gastric mill rhythm is distinct. These distinct rhythms are likely to result partly from different MCN1 activity levels under these two conditions and partly from the presence of additional GPR actions in the STG. These results support the hypothesis that different sensory systems differentially regulate neuronal circuit activity despite their convergent actions on a single subpopulation of projection neurons.
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Affiliation(s)
- Dawn M Blitz
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA
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Beenhakker MP, Blitz DM, Nusbaum MP. Long-lasting activation of rhythmic neuronal activity by a novel mechanosensory system in the crustacean stomatogastric nervous system. J Neurophysiol 2003; 91:78-91. [PMID: 14523066 PMCID: PMC6494456 DOI: 10.1152/jn.00741.2003] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sensory neurons enable neural circuits to generate behaviors appropriate for the current environmental situation. Here, we characterize the actions of a population (about 60) of bilaterally symmetric bipolar neurons identified within the inner wall of the cardiac gutter, a foregut structure in the crab Cancer borealis. These neurons, called the ventral cardiac neurons (VCNs), project their axons through the crab stomatogastric nervous system to influence neural circuits associated with feeding. Brief pressure application to the cardiac gutter transiently modulated the filtering motor pattern (pyloric rhythm) generated by the pyloric circuit within the stomatogastric ganglion (STG). This modulation included an increased speed of the pyloric rhythm and a concomitant decrease in the activity of the lateral pyloric neuron. Furthermore, 2 min of rhythmic pressure application to the cardiac gutter elicited a chewing motor pattern (gastric mill rhythm) generated by the gastric mill circuit in the STG that persisted for < or =30 min. These sensory actions on the pyloric and gastric mill circuits were mimicked by either ventral cardiac nerve or dorsal posterior esophageal nerve stimulation. VCN actions on the STG circuits required the activation of projection neurons in the commissural ganglia. A subset of the VCN actions on these projection neurons appeared to be direct and cholinergic. We propose that the VCN neurons are mechanoreceptors that are activated when food stored in the foregut applies an outward force, leading to the long-lasting activation of projection neurons required to initiate chewing and modify the filtering of chewed food.
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Affiliation(s)
- Mark P Beenhakker
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Abstract
How neuronal networks enable animals, humans included, to make coordinated movements is a continuing goal of neuroscience research. The stomatogastric nervous system of decapod crustaceans, which contains a set of distinct but interacting motor circuits, has contributed significantly to the general principles guiding our present understanding of how rhythmic motor circuits operate at the cellular level. This results from a detailed documentation of the circuit dynamics underlying motor pattern generation in this system as well as its modulation by individual transmitters and neurons.
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Affiliation(s)
- Michael P Nusbaum
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia 19104-6074, USA.
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