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Ingram R, Volianskis R, Georgiou J, Jane DE, Michael-Titus AT, Collingridge GL, Volianskis A. Incremental induction of NMDAR-STP and NMDAR-LTP in the CA1 area of ventral hippocampal slices relies on graded activation of discrete NMDA receptors. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230239. [PMID: 38853568 DOI: 10.1098/rstb.2023.0239] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 04/12/2024] [Indexed: 06/11/2024] Open
Abstract
N-methyl-d-aspartate receptor (NMDAR)-dependent short- and long-term types of potentiation (STP and LTP, respectively) are frequently studied in the CA1 area of dorsal hippocampal slices (DHS). Far less is known about the NMDAR dependence of STP and LTP in ventral hippocampal slices (VHS), where both types of potentiation are smaller in magnitude than in the DHS. Here, we first briefly review our knowledge about the NMDAR dependence of STP and LTP and some other forms of synaptic plasticity. We then show in new experiments that the decay of NMDAR-STP in VHS, similar to dorsal hippocampal NMDAR-STP, is not time- but activity-dependent. We also demonstrate that the induction of submaximal levels of NMDAR-STP and NMDAR-LTP in VHS differs from the induction of saturated levels of plasticity in terms of their sensitivity to subunit-preferring NMDAR antagonists. These data suggest that activation of distinct NMDAR subtypes in a population of neurons results in an incremental increase in the induction of different phases of potentiation with changing sensitivity to pharmacological agents. Differences in pharmacological sensitivity, which arise due to differences in the levels of agonist-evoked biological response, might explain the disparity of the results concerning NMDAR subunit involvement in the induction of NMDAR-dependent plasticity.This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Rachael Ingram
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Rasa Volianskis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - David E Jane
- Hello Bio Limited, Cabot Park, Avonmouth, Bristol, UK
| | - Adina T Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Graham L Collingridge
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Arturas Volianskis
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
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Tsotsokou G, Trompoukis G, Papatheodoropoulos C. Muscarinic Modulation of Synaptic Transmission and Short-Term Plasticity in the Dorsal and Ventral Hippocampus. Mol Cell Neurosci 2024; 129:103935. [PMID: 38703973 DOI: 10.1016/j.mcn.2024.103935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
Muscarinic neurotransmission is fundamentally involved in supporting several brain functions by modulating flow of information in brain neural circuits including the hippocampus which displays a remarkable functional segregation along its longitudinal axis. However, how muscarinic neuromodulation contributes to the functional segregation along the hippocampus remains unclear. In this study we show that the nonselective muscarinic receptor agonist carbachol similarly suppresses basal synaptic transmission in the dorsal and ventral CA1 hippocampal field, in a concentration-depended manner. Furthermore, using a ten-pulse stimulation train of varying frequency we found that carbachol changes the frequency filtering properties more in ventral than dorsal hippocampus by facilitating synaptic inputs at a wide range of input frequencies in the ventral compared with dorsal hippocampus. Using the M2 receptor antagonist gallamine and the M4 receptor antagonist tropicamide, we found that M2 receptors are involved in controlling basal synaptic transmission and short-term synaptic plasticity (STSP) in the ventral but not the dorsal hippocampus, while M4 receptors participate in modulating basal synaptic transmission and STSP in both segments of the hippocampus. These results were corroborated by the higher protein expression levels of M2 receptors in the ventral compared with dorsal hippocampus. We conclude that muscarinic transmission modulates excitatory synaptic transmission and short-term synaptic plasticity along the entire rat hippocampus by acting through M4 receptors and recruiting M2 receptors only in the ventral hippocampus. Furthermore, M4 receptors appear to exert a permissive role on the actions of M2 receptors on STSP in the ventral hippocampus. This dorsoventral differentiation of muscarinic modulation is expected to have important implications in information processing along the endogenous hippocampal circuitry.
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Affiliation(s)
- Giota Tsotsokou
- Laboratory of Physiology, University of Patras, Department of Medicine, Rion, Greece
| | - George Trompoukis
- Laboratory of Physiology, University of Patras, Department of Medicine, Rion, Greece
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3
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Anvari S, Javan M, Mirnajafi-Zadeh J, Fathollahi Y. Repeated Morphine Exposure Alters Temporoamonic-CA1 Synaptic Plasticity in Male Rat Hippocampus. Neuroscience 2024; 545:148-157. [PMID: 38513764 DOI: 10.1016/j.neuroscience.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 03/23/2024]
Abstract
In this study, the electrophysiological and biochemical consequences of repeated exposure to morphine in male rats on glutamatergic synaptic transmission, synaptic plasticity, the expression of GABA receptors and glutamate receptors at the temporoammonic-CA1 synapse along the longitudinal axis of the hippocampus (dorsal, intermediate, ventral, DH, IH, VH, respectively) were investigated. Slice electrophysiological methods, qRT-PCR, and western blotting techniques were used to characterize synaptic plasticity properties. We showed that repeated morphine exposure (RME) reduced excitatory synaptic transmission and ability for long-term potentiation (LTP) in the VH as well as eliminated the dorsoventral difference in paired-pulse responses. A decreased expression of NR2B subunit in the VH and an increased expression GABAA receptor of α1 and α5 subunits in the DH were observed following RME. Furthermore, RME did not affect the expression of NR2A, AMPA receptor subunits, and γ2GABAA and GABAB receptors in either segment of the hippocampus. In sum, the impact of morphine may differ depending on the region of the hippocampus studied. A distinct change in the short- and long-term synaptic plasticity along the hippocampus long axis due to repeated morphine exposure, partially mediated by a change in the expression profile of glutamatergic receptor subunits. These findings can be useful in further understanding the cellular mechanism underlying deficits in information storage and, more generally, cognitive processes resulting from chronic opioid abuse.
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Affiliation(s)
- Sohrab Anvari
- Department of Physiology, School of Medical Sciences, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran
| | - Mohammad Javan
- Department of Physiology, School of Medical Sciences, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, School of Medical Sciences, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Physiology, School of Medical Sciences, Tarbiat Modares University, PO Box 14115-111, Tehran, Iran.
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Ahmadi M, Rouhi N, Fathollahi Y, Shojaei A, Rezaei M, Rostami S, Saab BJ, Mirnajafi-Zadeh J. A Dual Effect of Dopamine on Hippocampal LTP and Cognitive Functions in Control and Kindled Mice. J Neurosci 2024; 44:e0926212023. [PMID: 38124004 PMCID: PMC10860576 DOI: 10.1523/jneurosci.0926-21.2023] [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: 05/01/2021] [Revised: 11/02/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
The impact of dopamine on synaptic plasticity and cognitive function following seizure is not well understood. Here, using optogenetics in the freely behaving animal, we examined exploratory behavior and short-term memory in control and kindled male mice during tonic stimulation of dopaminergic neurons within the ventral tegmental area (VTA). Furthermore, using field potential recording, we compared the effect of dopamine on synaptic plasticity in stratum radiatum and stratum oriens layers of both ventral and dorsal hippocampal CA1 regions, and again in both control and kindled male mice. Our results demonstrate that tonic stimulation of VTA dopaminergic neurons enhances novelty-driven exploration and short-term spatial memory in kindled mice, essentially rescuing the seizure-induced cognitive impairment. In addition, we found that dopamine has a dual effect on LTP in control versus kindled mice, such that application of dopamine prevented LTP induction in slices from control mice, but rescued LTP in slices taken from the kindled animal. Taken together, our results highlight the potential for dopaminergic modulation in improving synaptic plasticity and cognitive function following seizure.
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Affiliation(s)
- Mahboubeh Ahmadi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Nahid Rouhi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Yaghoub Fathollahi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Mahmoud Rezaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Sareh Rostami
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Bechara J Saab
- Preclinical Laboratory for Translational Research into Affective Disorders, DPPP, Psychiatric Hospital, University of Zurich, Zurich CH-8008, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH, Zurich 8057, Switzerland
- Mobio Interactive Pte. Ltd., 389637, Singapore, Republic of Singapore
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
- Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran 1411713116, Iran
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Tsotsokou G, Kouri V, Papatheodoropoulos C. α7 nicotinic acetylcholine receptors induce long-term synaptic enhancement in the dorsal but not ventral hippocampus. Synapse 2024; 78:e22285. [PMID: 38287475 DOI: 10.1002/syn.22285] [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: 08/08/2023] [Revised: 11/08/2023] [Accepted: 12/04/2023] [Indexed: 01/31/2024]
Abstract
Agents that positively modulate the activity of α7nAChRs are used as cognitive enhancers and for the treatment of hippocampus-dependent functional decline. However, it is not known whether the expression and the effects of α7nAChRs apply to the entire longitudinal axis of the hippocampus equally. Given that cholinergic system-involving hippocampal functions are not equally distributed along the hippocampus, we comparatively examined the expression and the effects of α7nAChRs on excitatory synaptic transmission between the dorsal and the ventral hippocampal slices from adult rats. We found that α7nAChRs are equally expressed in the CA1 field of the two segments of the hippocampus. However, activation of α7nAChRs by their highly selective agonist PNU 282987 induced a gradually developing increase in field excitatory postsynaptic potential only in the dorsal hippocampus. This long-term potentiation was not reversed upon application of nonselective nicotinic receptor antagonist mecamylamine, but the induction of potentiation was prevented by prior blockade of α7nAChRs by their antagonist MG 624. In contrast to the long-term synaptic plasticity, we found that α7nAChRs did not modulate short-term synaptic plasticity in either the dorsal or the ventral hippocampus. These results may have implications for the role that α7nAChRs play in specifically modulating functions that depend on the normal function of the dorsal hippocampus. We propose that hippocampal functions that rely on a direct α7 nAChR-mediated persistent enhancement of glutamatergic synaptic transmission are preferably supported by dorsal but not ventral hippocampal synapses.
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Affiliation(s)
- Giota Tsotsokou
- Department of Medicine, Laboratory of Physiology, University of Patras, Rion, Greece
| | - Vasiliki Kouri
- Department of Medicine, Laboratory of Physiology, University of Patras, Rion, Greece
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Mosleh M, Javan M, Fathollahi Y. The properties of long-term potentiation at SC-CA1/ TA-CA1 hippocampal synaptic pathways depends upon their input pathway activation patterns. IBRO Neurosci Rep 2023; 14:358-365. [PMID: 37020855 PMCID: PMC10067737 DOI: 10.1016/j.ibneur.2023.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/25/2023] [Indexed: 03/30/2023] Open
Abstract
Long-term potentiation (LTP) has been considered as a cellular mechanism of memory. Since the Schaffer collateral (SC) and temporoammonic (TA) inputs to CA1 are distinct synaptic pathways that could mediate different cognitive functions, this study was therefore aimed to separately study and compare the properties of LTP of these two synaptic pathways. In the current study we used slice electrophysiological methods to compare various properties of these two synaptic pathways in response to single, paired pulse stimulation, and to three standard protocols for inducing LTP: the high frequency electrical stimulation (HFS), theta-burst (TBS), and primed burst (PBs) stimulation. We found that the SC-CA1 synapses could produce bigger maximum synaptic responses than TA-CA1 synapses. In addition, we showed that paired-pulse ratios of the SC-CA1 synapses were higher than TA-CA1 synapses at certain inter-pulses intervals. Finally, we showed a higher LTP% was induced by PBs or TBS at the SC-CA1 synapse than the TA-CA1 synapse. Briefly, our findings suggest the differential basal synaptic transmission, paired-pulse evoked synaptic responses, and LTP exhibition of the hippocampal SC-CA1/ TA-CA1 synaptic pathways, which may rely on spontaneous and evoked activity pattern at the local circuit level.
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Anvari S, Foolad F, Javan M, Mirnajafi-Zadeh J, Fathollahi Y. A distinct impact of repeated morphine exposure on synaptic plasticity at Schaffer collateral-CA1, temporoammonic-CA1, and perforant pathway-dentate gyrus synapses along the longitudinal axis of the hippocampus. Hippocampus 2023; 33:47-62. [PMID: 36514833 DOI: 10.1002/hipo.23488] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022]
Abstract
We aimed to study how morphine affects synaptic transmission in the dentate gyrus and CA1 regions along the hippocampal long axis. For this, recording and measuring of field excitatory postsynaptic potentials (fEPSPs) were utilized to test the effects of repeated morphine exposure on paired-pulse evoked responses and long-term potentiation (LTP) at Schaffer collateral-CA1 (Sch-CA1), temporoammonic-CA1 (TA-CA1) and perforant pathway-dentate gyrus (PP-DG) synapses in transverse slices from the dorsal (DH), intermediate (IH), and ventral (VH) hippocampus in adult male rats. After repeated morphine exposure, the expression of opioid receptors and the α1 and α5 GABAA subunits were also examined. We found that repeated morphine exposure blunt the difference between the DH and the VH in their basal levels of synaptic transmission at Sch-CA1 synapses that were seen in the control groups. Significant paired-pulse facilitation of excitatory synaptic transmission was observed at Sch-CA1 synapses in slices taken from all three hippocampal segments as well as at PP-DG synapses in slices taken from the VH segment in the morphine-treated groups as compared to the control groups. Interestingly, significant paired-pulse inhibition of excitatory synaptic transmission was observed at TA-CA1 synapses in the DH slices from the morphine-treated group as compared to the control group. While primed-burst stimulation (a protocol reflecting normal neuronal firing) induced a robust LTP in hippocampal subfields in all control groups, resulting in a decaying LTP at TA-CA1 synapses in the VH slices and at PP-DG synapses in both the IH and VH slices taken from the morphine-treated rats. In the DH of morphine-treated rats, we found increased levels of the mRNAs encoding the α1 and α5 GABAA subunits as compared to the control group. Taken together, these findings suggest the potential mechanisms through which repeated morphine exposure causes differential changes in circuit excitability and synaptic plasticity in the dentate gyrus and CA1 regions along the hippocampal long axis.
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Affiliation(s)
- Sohrab Anvari
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Forough Foolad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Javan
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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A. Samara M, Oikonomou GD, Trompoukis G, Madarou G, Adamopoulou M, Papatheodoropoulos C. Septotemporal variation in modulation of synaptic transmission, paired-pulse ratio and frequency facilitation/depression by adenosine and GABA B receptors in the rat hippocampus. Brain Neurosci Adv 2022; 6:23982128221106315. [PMID: 35782711 PMCID: PMC9240614 DOI: 10.1177/23982128221106315] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 05/19/2022] [Indexed: 11/26/2022] Open
Abstract
Short-term synaptic plasticity represents a fundamental mechanism in
neural information processing and is regulated by neuromodulators.
Here, using field recordings from the CA1 region of adult rat
hippocampal slices, we show that excitatory synaptic transmission is
suppressed by strong but not moderate activation of adenosine
A1 receptors by
2-Chloro-N6-cyclopentyladenosine (CCPA) more in the dorsal
than the ventral hippocampus; in contrast, both mild and strong
activation of GABAB receptors by baclofen (1 μM, 10 μM)
suppress synaptic transmission more in the ventral than the dorsal
hippocampus. Using a 10-pulse stimulation train of variable frequency,
we found that CCPA modulates short-term synaptic plasticity
independently of the suppression of synaptic transmission in both
segments of the hippocampus and at stimulation frequencies greater
than 10 Hz. However, specifically regarding the paired-pulse ratio
(PPR) and frequency facilitation/depression (FF/D) we found
significant drug action before but not after adjusting conditioning
responses to control levels. Activation of GABABRs by
baclofen suppressed synaptic transmission more in the ventral than the
dorsal hippocampus. Furthermore, relatively high (10 μM) but not low
(1 μM) baclofen concentration enhanced both PPR and FF in both
hippocampal segments at stimulation frequencies greater than 1 Hz,
independently of the suppression of synaptic transmission by baclofen.
These results show that A1Rs and GABABRs control
synaptic transmission more effectively in the dorsal and the ventral
hippocampus, respectively, and suggest that these receptors modulate
PPR and FF/D at different frequency bands of afferent input, in both
segments of the hippocampus.
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Affiliation(s)
- Maria A. Samara
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - George D. Oikonomou
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - George Trompoukis
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - Georgia Madarou
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - Maria Adamopoulou
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
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de Siqueira Mendes FDCC, de Almeida MNF, Falsoni M, Andrade MLF, Felício APG, da Paixão LTVB, Júnior FLDA, Anthony DC, Brites D, Diniz CWP, Sosthenes MCK. The Sedentary Lifestyle and Masticatory Dysfunction: Time to Review the Contribution to Age-Associated Cognitive Decline and Astrocyte Morphotypes in the Dentate Gyrus. Int J Mol Sci 2022; 23:ijms23116342. [PMID: 35683023 PMCID: PMC9180988 DOI: 10.3390/ijms23116342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 02/01/2023] Open
Abstract
As aging and cognitive decline progresses, the impact of a sedentary lifestyle on the appearance of environment-dependent cellular morphologies in the brain becomes more apparent. Sedentary living is also associated with poor oral health, which is known to correlate with the rate of cognitive decline. Here, we will review the evidence for the interplay between mastication and environmental enrichment and assess the impact of each on the structure of the brain. In previous studies, we explored the relationship between behavior and the morphological features of dentate gyrus glial fibrillary acidic protein (GFAP)-positive astrocytes during aging in contrasting environments and in the context of induced masticatory dysfunction. Hierarchical cluster and discriminant analysis of GFAP-positive astrocytes from the dentate gyrus molecular layer revealed that the proportion of AST1 (astrocyte arbors with greater complexity phenotype) and AST2 (lower complexity) are differentially affected by environment, aging and masticatory dysfunction, but the relationship is not straightforward. Here we re-evaluated our previous reconstructions by comparing dorsal and ventral astrocyte morphologies in the dentate gyrus, and we found that morphological complexity was the variable that contributed most to cluster formation across the experimental groups. In general, reducing masticatory activity increases astrocyte morphological complexity, and the effect is most marked in the ventral dentate gyrus, whereas the effect of environment was more marked in the dorsal dentate gyrus. All morphotypes retained their basic structural organization in intact tissue, suggesting that they are subtypes with a non-proliferative astrocyte profile. In summary, the increased complexity of astrocytes in situations where neuronal loss and behavioral deficits are present is counterintuitive, but highlights the need to better understand the role of the astrocyte in these conditions.
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Affiliation(s)
- Fabíola de Carvalho Chaves de Siqueira Mendes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
- Curso de Medicina, Centro Universitário do Estado do Pará, Belém 66613-903, PA, Brazil
| | - Marina Negrão Frota de Almeida
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Manoela Falsoni
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Marcia Lorena Ferreira Andrade
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - André Pinheiro Gurgel Felício
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Luisa Taynah Vasconcelos Barbosa da Paixão
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Fábio Leite do Amaral Júnior
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Daniel Clive Anthony
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK;
| | - Dora Brites
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-004 Lisbon, Portugal;
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, 1649-004 Lisbon, Portugal
| | - Cristovam Wanderley Picanço Diniz
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Marcia Consentino Kronka Sosthenes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
- Correspondence:
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10
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Danan D, Todder D, Zohar J, Cohen H. Is PTSD-Phenotype Associated with HPA-Axis Sensitivity? Feedback Inhibition and Other Modulating Factors of Glucocorticoid Signaling Dynamics. Int J Mol Sci 2021; 22:ijms22116050. [PMID: 34205191 PMCID: PMC8200046 DOI: 10.3390/ijms22116050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 01/12/2023] Open
Abstract
Previously, we found that basal corticosterone pulsatility significantly impacts the vulnerability for developing post-traumatic stress disorder (PTSD). Rats that exhibited PTSD-phenotype were characterized by blunted basal corticosterone pulsatility amplitude and a blunted corticosterone response to a stressor. This study sought to identify the mechanisms underlining both the loss of pulsatility and differences in downstream responses. Serial blood samples were collected manually via jugular vein cannula at 10-min intervals to evaluate suppression of corticosterone following methylprednisolone administration. The rats were exposed to predator scent stress (PSS) after 24 h, and behavioral responses were assessed 7 days post-exposure for retrospective classification into behavioral response groups. Brains were harvested for measurements of the glucocorticoid receptor, mineralocorticoid receptor, FK506-binding protein-51 and arginine vasopressin in specific brain regions to assess changes in hypothalamus–pituitary–adrenal axis (HPA) regulating factors. Methylprednisolone produced greater suppression of corticosterone in the PTSD-phenotype group. During the suppression, the PTSD-phenotype rats showed a significantly more pronounced pulsatile activity. In addition, the PTSD-phenotype group showed distinct changes in the ventral and dorsal CA1, dentate gyrus as well as in the paraventricular nucleus and supra-optic nucleus. These results demonstrate a pre-trauma vulnerability state that is characterized by an over-reactivity of the HPA and changes in its regulating factors.
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Affiliation(s)
- Dor Danan
- Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84170, Israel; (D.D.); (D.T.)
| | - Doron Todder
- Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84170, Israel; (D.D.); (D.T.)
| | - Joseph Zohar
- Post-Trauma Center, Sheba Medical Center, Tel Aviv 52621, Israel;
| | - Hagit Cohen
- Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84170, Israel; (D.D.); (D.T.)
- Correspondence: ; Tel.: +972-544-369106
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11
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Hammoud H, Netsyk O, Tafreshiha AS, Korol SV, Jin Z, Li J, Birnir B. Insulin differentially modulates GABA signalling in hippocampal neurons and, in an age-dependent manner, normalizes GABA-activated currents in the tg-APPSwe mouse model of Alzheimer's disease. Acta Physiol (Oxf) 2021; 232:e13623. [PMID: 33559388 DOI: 10.1111/apha.13623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023]
Abstract
AIM We examined if tonic γ-aminobutyric acid (GABA)-activated currents in primary hippocampal neurons were modulated by insulin in wild-type and tg-APPSwe mice, an Alzheimer's disease (AD) model. METHODS GABA-activated currents were recorded in dentate gyrus (DG) granule cells and CA3 pyramidal neurons in hippocampal brain slices, from 8 to 10 weeks old (young) wild-type mice and in dorsal DG granule cells in adult, 5-6 and 10-12 (aged) months old wild-type and tg-APPSwe mice, in the absence or presence of insulin, by whole-cell patch-clamp electrophysiology. RESULTS In young mice, insulin (1 nmol/L) enhanced the total spontaneous inhibitory postsynaptic current (sIPSCT ) density in both dorsal and ventral DG granule cells. The extrasynaptic current density was only increased by insulin in dorsal CA3 pyramidal neurons. In absence of action potentials, insulin enhanced DG granule cells and dorsal CA3 pyramidal neurons miniature IPSC (mIPSC) frequency, consistent with insulin regulation of presynaptic GABA release. sIPSCT densities in DG granule cells were similar in wild-type and tg-APPSwe mice at 5-6 months but significantly decreased in aged tg-APPSwe mice where insulin normalized currents to wild-type levels. The extrasynaptic current density was increased in tg-APPSwe mice relative to wild-type littermates but, only in aged tg-APPSwe mice did insulin decrease and normalize the current. CONCLUSION Insulin effects on GABA signalling in hippocampal neurons are selective while multifaceted and context-based. Not only is the response to insulin related to cell-type, hippocampal axis-location, age of animals and disease but also to the subtype of neuronal inhibition involved, synaptic or extrasynaptic GABAA receptors-activated currents.
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Affiliation(s)
- Hayma Hammoud
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Olga Netsyk
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | | | - Sergiy V. Korol
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Zhe Jin
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Jin‐Ping Li
- Department of Medical Biochemistry and Microbiology Uppsala University Uppsala Sweden
| | - Bryndis Birnir
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
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12
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Albrecht A, Redavide E, Regev-Tsur S, Stork O, Richter-Levin G. Hippocampal GABAergic interneurons and their co-localized neuropeptides in stress vulnerability and resilience. Neurosci Biobehav Rev 2020; 122:229-244. [PMID: 33188820 DOI: 10.1016/j.neubiorev.2020.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/05/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Studies in humans and rodents suggest a critical role for the hippocampal formation in cognition and emotion, but also in the adaptation to stressful events. Successful stress adaptation promotes resilience, while its failure may lead to stress-induced psychopathologies such as depression and anxiety disorders. Hippocampal architecture and physiology is shaped by its strong control of activity via diverse classes of inhibitory interneurons that express typical calcium binding proteins and neuropeptides. Celltype-specific opto- and chemogenetic intervention strategies that take advantage of these biochemical markers have bolstered our understanding of the distinct role of different interneurons in anxiety, fear and stress adaptation. Moreover, some of the signature proteins of GABAergic interneurons have a potent impact on emotion and cognition on their own, making them attractive targets for interventions. In particular, neuropeptide Y is a promising endogenous agent for mediating resilience against severe stress. In this review, we evaluate the role of the major types of interneurons across hippocampal subregions in the adaptation to chronic and acute stress and to emotional memory formation.
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Affiliation(s)
- Anne Albrecht
- Institute of Anatomy, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany; Center for Behavioral Brain Science, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Elisa Redavide
- Institute of Anatomy, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany; Center for Behavioral Brain Science, Universitätsplatz 2, 39106 Magdeburg, Germany; Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany; Institute of Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
| | - Stav Regev-Tsur
- Sagol Department of Neurobiology, University of Haifa, 199 Aba-Hushi Avenue, 3498838 Haifa, Israel; The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, 199 Aba-Hushi Avenue, 3498838 Haifa, Israel.
| | - Oliver Stork
- Center for Behavioral Brain Science, Universitätsplatz 2, 39106 Magdeburg, Germany; Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
| | - Gal Richter-Levin
- Sagol Department of Neurobiology, University of Haifa, 199 Aba-Hushi Avenue, 3498838 Haifa, Israel; The Integrated Brain and Behavior Research Center (IBBR), University of Haifa, 199 Aba-Hushi Avenue, 3498838 Haifa, Israel; Psychology Department, University of Haifa199 Aba-Hushi Avenue, 3498838 Haifa, Israel.
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13
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Rattner A, Terrillion CE, Jou C, Kleven T, Hu SF, Williams J, Hou Z, Aggarwal M, Mori S, Shin G, Goff LA, Witter MP, Pletnikov M, Fenton AA, Nathans J. Developmental, cellular, and behavioral phenotypes in a mouse model of congenital hypoplasia of the dentate gyrus. eLife 2020; 9:62766. [PMID: 33084572 PMCID: PMC7577738 DOI: 10.7554/elife.62766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 09/29/2020] [Indexed: 01/03/2023] Open
Abstract
In the hippocampus, a widely accepted model posits that the dentate gyrus improves learning and memory by enhancing discrimination between inputs. To test this model, we studied conditional knockout mice in which the vast majority of dentate granule cells (DGCs) fail to develop – including nearly all DGCs in the dorsal hippocampus – secondary to eliminating Wntless (Wls) in a subset of cortical progenitors with Gfap-Cre. Other cells in the Wlsfl/-;Gfap-Cre hippocampus were minimally affected, as determined by single nucleus RNA sequencing. CA3 pyramidal cells, the targets of DGC-derived mossy fibers, exhibited normal morphologies with a small reduction in the numbers of synaptic spines. Wlsfl/-;Gfap-Cre mice have a modest performance decrement in several complex spatial tasks, including active place avoidance. They were also modestly impaired in one simpler spatial task, finding a visible platform in the Morris water maze. These experiments support a role for DGCs in enhancing spatial learning and memory.
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Affiliation(s)
- Amir Rattner
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Chantelle E Terrillion
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Claudia Jou
- Department of Physiology and Pharmacology, Robert F. Furchgott Center for Behavioral Neuroscience, State University of New York, Downstate Medical Center, Brooklyn, United States
| | - Tina Kleven
- Kavli Institute for Systems Neuroscience and Center for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Shun Felix Hu
- Department of Physiology and Pharmacology, Robert F. Furchgott Center for Behavioral Neuroscience, State University of New York, Downstate Medical Center, Brooklyn, United States
| | - John Williams
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Zhipeng Hou
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Manisha Aggarwal
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Susumu Mori
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Gloria Shin
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Loyal A Goff
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Menno P Witter
- Kavli Institute for Systems Neuroscience and Center for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Mikhail Pletnikov
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, United States
| | - André A Fenton
- Department of Physiology and Pharmacology, Robert F. Furchgott Center for Behavioral Neuroscience, State University of New York, Downstate Medical Center, Brooklyn, United States.,Center for Neural Science, New York University, New York, United States.,Neuroscience Institute at the New York University Langone Medical Center, New York University, New York, United States
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, United States
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14
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Trompoukis G, Papatheodoropoulos C. Dorsal-Ventral Differences in Modulation of Synaptic Transmission in the Hippocampus. Front Synaptic Neurosci 2020; 12:24. [PMID: 32625076 PMCID: PMC7316154 DOI: 10.3389/fnsyn.2020.00024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/14/2020] [Indexed: 11/17/2022] Open
Abstract
Functional diversification along the longitudinal axis of the hippocampus is a rapidly growing concept. Modulation of synaptic transmission by neurotransmitter receptors may importantly contribute to specialization of local intrinsic network function along the hippocampus. In the present study, using transverse slices from the dorsal and the ventral hippocampus of adult rats and recordings of evoked field postsynaptic excitatory potentials (fEPSPs) from the CA1 stratum radiatum, we aimed to compare modulation of synaptic transmission between the dorsal and the ventral hippocampus. We found that transient heterosynaptic depression (tHSD, <2 s), a physiologically relevant phenomenon of regulation of excitatory synaptic transmission induced by paired stimulation of two independent inputs to stratum radiatum of CA1 field, has an increased magnitude and duration in the ventral hippocampus, presumably contributing to increased input segregation in this segment of the hippocampus. GABAB receptors, GABAA receptors, adenosine A1 receptors and L-type voltage-gated calcium channels appear to contribute differently to tHSD in the two hippocampal segments; GABABRs play a predominant role in the ventral hippocampus while both GABABRs and A1Rs play important roles in the dorsal hippocampus. Activation of GABAB receptors by an exogenous agonist, baclofen, robustly and reversibly modulated both the initial fast and the late slow components of excitatory synaptic transmission, expressed by the fEPSPslope and fEPSP decay time constant (fEPSPτ), respectively. Specifically, baclofen suppressed fEPSP slope more in the ventral than in the dorsal hippocampus and enhanced fEPSPτ more in the dorsal than in the ventral hippocampus. Also, baclofen enhanced paired-pulse facilitation in the two hippocampal segments similarly. Blockade of GABAB receptors did not affect basal paired-pulse facilitation in either hippocampal segment. We propose that the revealed dorsal-ventral differences in modulation of synaptic transmission may provide a means for specialization of information processing in the local neuronal circuits, thereby significantly contributing to diversifying neuronal network functioning along the dorsal-ventral axis of hippocampus.
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Affiliation(s)
- George Trompoukis
- Laboratory of Physiology, Department of Medicine, University of Patras, Patras, Greece
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15
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Netsyk O, Hammoud H, Korol SV, Jin Z, Tafreshiha AS, Birnir B. Tonic
GABA
‐activated synaptic and extrasynaptic currents in dentate gyrus granule cells and
CA3
pyramidal neurons along the mouse hippocampal dorsoventral axis. Hippocampus 2020; 30:1146-1157. [DOI: 10.1002/hipo.23245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Olga Netsyk
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Hayma Hammoud
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Sergiy V. Korol
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Zhe Jin
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | | | - Bryndis Birnir
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
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16
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Koutsoumpa A, Papatheodoropoulos C. Short-term dynamics of input and output of CA1 network greatly differ between the dorsal and ventral rat hippocampus. BMC Neurosci 2019; 20:35. [PMID: 31331291 PMCID: PMC6647178 DOI: 10.1186/s12868-019-0517-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 07/12/2019] [Indexed: 12/13/2022] Open
Abstract
Background The functional heterogeneity of the hippocampus along its longitudinal axis at the level of behavior is an established concept; however, the neurobiological mechanisms are still unknown. Diversifications in the functioning of intrinsic hippocampal circuitry including short-term dynamics of synaptic inputs and neuronal output, that are important determinants of information processing in the brain, may profoundly contribute to functional specializations along the hippocampus. The objectives of the present study were the examination of the role of the GABAA receptor-mediated inhibition, the μ-opioid receptors and the effect of stimulation intensity on the dynamics of both synaptic input and neuronal output of CA1 region in the dorsal and ventral hippocampus. We used recordings of field potentials from adult rat hippocampal slices evoked by brief repetitive activation of Schaffer collaterals. Results We find that the local CA1 circuit of the dorsal hippocampus presents a remarkably increased dynamic range of frequency-dependent short-term changes in both input and output, ranging from strong facilitation to intense depression at low and high stimulation frequencies respectively. Furthermore, the input–output relationship in the dorsal CA1 circuit is profoundly influenced by frequency and time of presynaptic activation. Strikingly, the ventral hippocampus responds mostly with depression, displaying a rather monotonous input–output relationship over frequency and time. Partial blockade of GABAA receptor-mediated transmission (by 5 μM picrotoxin) profoundly influences input and output dynamics in the dorsal hippocampus but affected only the neuronal output in the ventral hippocampus. M-opioid receptors control short-term dynamics of input and output in the dorsal hippocampus but they play no role in the ventral hippocampus. Conclusion The results demonstrate that information processing by CA1 local network is highly diversified between the dorsal and ventral hippocampus. Transient detection of incoming patterns of activity and frequency-dependent sustained signaling of amplified neuronal information may be assigned to the ventral and dorsal hippocampal circuitry respectively. This disparity should have profound implications for the functional roles ascribed to distinct segments along the long axis of the hippocampus. Electronic supplementary material The online version of this article (10.1186/s12868-019-0517-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andriana Koutsoumpa
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, 26504, Rion, Greece.,Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
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17
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β-adrenergic receptors reduce the threshold for induction and stabilization of LTP and enhance its magnitude via multiple mechanisms in the ventral but not the dorsal hippocampus. Neurobiol Learn Mem 2018; 151:71-84. [PMID: 29653257 DOI: 10.1016/j.nlm.2018.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 03/19/2018] [Accepted: 04/07/2018] [Indexed: 12/27/2022]
Abstract
The hippocampus is a functionally heterogeneous structure with the cognitive and emotional signal processing ascribed to the dorsal (DH) and the ventral hippocampus (VH) respectively. However, the underlying mechanisms are poorly understood. Noradrenaline is released in hippocampus during emotional arousal modulating synaptic plasticity and memory consolidation through activation of β adrenergic receptors (β-ARs). Using recordings of field excitatory postsynaptic potentials from the CA1 field of adult rat hippocampal slices we demonstrate that long-term potentiation (LTP) induced either by theta-burst stimulation (TBS) that mimics a physiological firing pattern of hippocampal neurons or by high-frequency stimulation is remarkably more sensitive to β-AR activation in VH than in DH. Thus, pairing of subthreshold primed burst stimulation with activation of β-ARs by their agonist isoproterenol (1 μM) resulted in a reliable induction of NMDA receptor-dependent LTP in the VH without affecting LTP in the DH. Activation of β-ARs by isoproterenol during application of intense TBS increased the magnitude of LTP in both hippocampal segments but facilitated voltage-gated calcium channel-dependent LTP in VH only. Endogenous β-AR activation contributed to the stabilization and the magnitude of LTP in VH but not DH as demonstrated by the effects of the β-ARs antagonist propranolol (10 μM). Exogenous (but not endogenous) β-AR activation strongly increased TBS-induced facilitation of postsynaptic excitability in VH. In DH, isoproterenol only produced a moderate and GABAergic inhibition-dependent enhancement in the facilitation of synaptic burst responses. Paired-pulse facilitation did not change with LTP at any experimental condition suggesting that expression of LTP does not involve presynaptic mechanisms. These findings suggest that β-AR may act as a switch that selectively promotes synaptic plasticity in VH through multiple ways and provide thus a first clue to mechanisms that underlie VH involvement in emotionality.
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18
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Papaleonidopoulos V, Trompoukis G, Koutsoumpa A, Papatheodoropoulos C. A gradient of frequency-dependent synaptic properties along the longitudinal hippocampal axis. BMC Neurosci 2017; 18:79. [PMID: 29233091 PMCID: PMC5727934 DOI: 10.1186/s12868-017-0398-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/05/2017] [Indexed: 12/29/2022] Open
Abstract
Background The hippocampus is a functionally heterogeneous brain structure and specializations of the intrinsic neuronal network may crucially support the functional segregation along the longitudinal axis of the hippocampus. Short-term synaptic plasticity plays fundamental roles in information processing and may be importantly involved in diversifying the properties of local neuronal network along the hippocampus long axis. Therefore, we aimed to examine the properties of the cornu ammonis 1 (CA1) synapses along the entire dorsoventral axis of the rat hippocampus using field excitatory postsynaptic potentials from transverse rat hippocampal slices and a frequency stimulation paradigm. Results Applying a ten-pulse stimulus train at frequencies from 0.1 to 100 Hz to the Schaffer collaterals we found a gradually diversified pattern of frequency-dependent synaptic effects along the dorsoventral hippocampus axis. The first conditioned response was facilitated along the whole hippocampus for stimulus frequencies 10–40 Hz. However, steady-state responses or averaged responses generally ranged from maximum synaptic facilitation in the most dorsal segment of the hippocampus to maximum synaptic depression in the most ventral segment of the hippocampus. In particular, dorsal synapses facilitated for stimulus frequency up to 50 Hz while they depressed at higher frequencies (75–100 Hz). Facilitation at dorsal synapses was maximal at stimulus frequency of 20 Hz. On the contrary, the most ventral synapses showed depression regardless of the stimulus frequency, only displaying a transient facilitation at the beginning of 10–50 Hz stimulation. Importantly, the synapses in the medial hippocampus displayed a transitory behavior. Finally, as a whole the hippocampal synapses maximally facilitated at 20 Hz and increasingly depressed at 50–100 Hz. Conclusion The short-term synaptic dynamics change gradually along the hippocampal long axis in a frequency-dependent fashion conveying distinct properties of information processing to successive segments of the structure, thereby crucially supporting functional segregation along the dorsoventral axis of the hippocampus.
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Affiliation(s)
| | - George Trompoukis
- Department of Medicine, Laboratory of Physiology, University of Patras, 26504, Rion, Greece
| | - Andriana Koutsoumpa
- Department of Medicine, Laboratory of Physiology, University of Patras, 26504, Rion, Greece
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19
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Prominent differences in sharp waves, ripples and complex spike bursts between the dorsal and the ventral rat hippocampus. Neuroscience 2017; 352:131-143. [DOI: 10.1016/j.neuroscience.2017.03.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/17/2022]
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20
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Differential Regulation of NMDA Receptor-Mediated Transmission by SK Channels Underlies Dorsal-Ventral Differences in Dynamics of Schaffer Collateral Synaptic Function. J Neurosci 2017; 37:1950-1964. [PMID: 28093473 DOI: 10.1523/jneurosci.3196-16.2017] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/27/2016] [Accepted: 01/07/2017] [Indexed: 11/21/2022] Open
Abstract
Behavioral, physiological, and anatomical evidence indicates that the dorsal and ventral zones of the hippocampus have distinct roles in cognition. How the unique functions of these zones might depend on differences in synaptic and neuronal function arising from the strikingly different gene expression profiles exhibited by dorsal and ventral CA1 pyramidal cells is unclear. To begin to address this question, we investigated the mechanisms underlying differences in synaptic transmission and plasticity at dorsal and ventral Schaffer collateral (SC) synapses in the mouse hippocampus. We find that, although basal synaptic transmission is similar, SC synapses in the dorsal and ventral hippocampus exhibit markedly different responses to θ frequency patterns of stimulation. In contrast to dorsal hippocampus, θ frequency stimulation fails to elicit postsynaptic complex-spike bursting and does not induce LTP at ventral SC synapses. Moreover, EPSP-spike coupling, a process that strongly influences information transfer at synapses, is weaker in ventral pyramidal cells. Our results indicate that all these differences in postsynaptic function are due to an enhanced activation of SK-type K+ channels that suppresses NMDAR-dependent EPSP amplification at ventral SC synapses. Consistent with this, mRNA levels for the SK3 subunit of SK channels are significantly higher in ventral CA1 pyramidal cells. Together, our findings indicate that a dorsal-ventral difference in SK channel regulation of NMDAR activation has a profound effect on the transmission, processing, and storage of information at SC synapses and thus likely contributes to the distinct roles of the dorsal and ventral hippocampus in different behaviors.SIGNIFICANCE STATEMENT Differences in short- and long-term plasticity at Schaffer collateral (SC) synapses in the dorsal and ventral hippocampus likely contribute importantly to the distinct roles of these regions in cognition and behavior. Although dorsal and ventral CA1 pyramidal cells exhibit markedly different gene expression profiles, how these differences influence plasticity at SC synapses is unclear. Here we report that increased mRNA levels for the SK3 subunit of SK-type K+ channels in ventral pyramidal cells is associated with an enhanced activation of SK channels that strongly suppresses NMDAR activation at ventral SC synapses. This leads to striking differences in multiple aspects of synaptic transmission at dorsal and ventral SC synapses and underlies the reduced ability of ventral SC synapses to undergo LTP.
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21
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Kouvaros S, Papatheodoropoulos C. Theta burst stimulation-induced LTP: Differences and similarities between the dorsal and ventral CA1 hippocampal synapses. Hippocampus 2016; 26:1542-1559. [DOI: 10.1002/hipo.22655] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Stylianos Kouvaros
- Laboratory of Physiology, Department of Medicine; School of Health Sciences, University of Patras; Rion Greece
| | - Costas Papatheodoropoulos
- Laboratory of Physiology, Department of Medicine; School of Health Sciences, University of Patras; Rion Greece
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22
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Papatheodoropoulos C, Kouvaros S. High-frequency stimulation-induced synaptic potentiation in dorsal and ventral CA1 hippocampal synapses: the involvement of NMDA receptors, mGluR5, and (L-type) voltage-gated calcium channels. ACTA ACUST UNITED AC 2016; 23:460-4. [PMID: 27531836 PMCID: PMC4986856 DOI: 10.1101/lm.042531.116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/24/2016] [Indexed: 11/24/2022]
Abstract
The ability of the ventral hippocampus (VH) for long-lasting long-term potentiation (LTP) and the mechanisms underlying its lower ability for short-lasting LTP compared with the dorsal hippocampus (DH) are unknown. Using recordings of field excitatory postsynaptic potentials (EPSPs) from the CA1 field of adult rat hippocampal slices, we found that 200-Hz stimulation induced nondecremental LTP that was maintained for at least 7 h and was greater in the DH than in the VH. The interaction of NMDA receptors with L-type voltage-dependent calcium channels appeared to be more effective in the DH than in the VH. Furthermore, the LTP was significantly enhanced in the DH only, between 2 and 5 h post-tetanus. Furthermore, the mGluR5 contributed to the post-tetanic potentiation more in the VH than in the DH.
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Affiliation(s)
| | - Stylianos Kouvaros
- Laboratory of Physiology, Department of Medicine, University of Patras, 26504, Rion, Greece
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23
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Kouvaros S, Papatheodoropoulos C. Major dorsoventral differences in the modulation of the local CA1 hippocampal network by NMDA, mGlu5, adenosine A2A and cannabinoid CB1 receptors. Neuroscience 2016; 317:47-64. [PMID: 26762803 DOI: 10.1016/j.neuroscience.2015.12.059] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/23/2015] [Accepted: 12/30/2015] [Indexed: 11/29/2022]
Abstract
Recent research points to diversification in the local neuronal circuitry between dorsal (DH) and ventral (VH) hippocampus that may be involved in the large-scale functional segregation along the long axis of the hippocampus. Here, using CA1 field recordings from rat hippocampal slices, we show that activation of N-methyl-d-aspartate receptors (NMDARs) reduced excitatory transmission more in VH than in DH, with an adenosine A1 receptor-independent mechanism, and reduced inhibition and enhanced postsynaptic excitability only in DH. Strikingly, co-activation of metabotropic glutamate receptor-5 (mGluR5) with NMDAR, by CHPG and NMDA respectively, strongly potentiated the effects of NMDAR in DH but had not any potentiating effect in VH. Furthermore, the synergistic actions in DH were occluded by blockade of adenosine A2A receptors (A2ARs) by their antagonist ZM 241385 demonstrating a tonic action of these receptors in DH. Exogenous activation of A2ARs by 4-[2-[[6-amino-9-(N-ethyl-β-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680) did not change the effects of mGluR5-NMDAR co-activation in either hippocampal pole. Importantly, blockade of cannabinoid CB1 receptors (CB1Rs) by their antagonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide (AM 281) restricted the synergistic actions of mGluR5-NMDARs on excitatory synaptic transmission and postsynaptic excitability and abolished their effect on inhibition. Furthermore, AM 281 increased the excitatory transmission only in DH indicating that CB1Rs were tonically active in DH but not VH. Removing the magnesium ions from the perfusion medium neither stimulated the interaction between mGluR5 and NMDAR in VH nor augmented the synergy of the two receptors in DH. These findings show that the NMDAR-dependent modulation of fundamental parameters of the local neuronal network, by mGluR5, A2AR and CB1R, markedly differs between DH and VH. We propose that the higher modulatory role of A2AR and mGluR5, in combination with the role of CB1Rs, provide DH with higher functional flexibility of its NMDARs, compared with VH.
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Affiliation(s)
- S Kouvaros
- Laboratory of Physiology, Department of Medicine, School of Health Sciences, University of Patras, 26504 Rion, Greece
| | - C Papatheodoropoulos
- Laboratory of Physiology, Department of Medicine, School of Health Sciences, University of Patras, 26504 Rion, Greece.
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Papatheodoropoulos C. Higher intrinsic network excitability in ventral compared with the dorsal hippocampus is controlled less effectively by GABAB receptors. BMC Neurosci 2015; 16:75. [PMID: 26556486 PMCID: PMC4641374 DOI: 10.1186/s12868-015-0213-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/04/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Elucidating specializations of the intrinsic neuronal network between the dorsal and the ventral hippocampus is a recently emerging area of research that is expected to help us understand the mechanisms underlying large scale functional diversification along the hippocampus. The aim of this study was to characterize spontaneous network activity between the dorsal and the ventral hippocampus induced under conditions of partial or complete blockade of GABAergic inhibition (i.e. disinhibition). RESULTS Using field recordings from the CA3 and CA1 fields of hippocampal slices from adult rats I found that ventral compared with dorsal hippocampus slices displayed higher propensity for and higher frequency of occurrence of spontaneous field potentials (spfps) at every level of disinhibition. Also NMDA receptor-depended spfps (spfps(-nmda)) occurred with higher probability more frequently and were larger in the ventral compared with the dorsal hippocampus. Importantly, blockade of GABA(B) receptors produced a stronger effect in enhancing the probability of generation of spfps and spfps(-nmda) in the dorsal compared with the ventral hippocampal slices and increased spfps(-nmda) only in dorsal slices. CONCLUSION These results demonstrate a higher intrinsic neuronal excitability of the ventral compared with the dorsal local circuitry with the considerable contribution of NMDA receptors. Furthermore, the GABA(B) receptors control the total and the NMDA receptor-dependent excitation much less effectively in the ventral part of the hippocampus. It is proposed that NMDA and GABA(B) receptors significantly contribute to differentiate local network dynamics between the dorsal and the ventral hippocampus with important implications in the information processing performed along the long hippocampal axis.
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Affiliation(s)
- Costas Papatheodoropoulos
- Laboratory of Physiology, Department of Medicine, School of Health Sciences, University of Patras, Rion, 26504, Patras, Greece.
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