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Beckmann D, Feldmann M, Shchyglo O, Manahan-Vaughan D. Hippocampal Synaptic Plasticity, Spatial Memory, and Neurotransmitter Receptor Expression Are Profoundly Altered by Gradual Loss of Hearing Ability. Cereb Cortex 2020; 30:4581-4596. [PMID: 32202614 PMCID: PMC7325716 DOI: 10.1093/cercor/bhaa061] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/20/2020] [Accepted: 02/12/2020] [Indexed: 12/27/2022] Open
Abstract
Sensory information comprises the substrate from which memories are created. Memories of spatial sensory experience are encoded by means of synaptic plasticity in the hippocampus. Hippocampal dependency on sensory information is highlighted by the fact that sudden and complete loss of a sensory modality results in an impairment of hippocampal function that persists for months. Effects are accompanied by extensive changes in the expression of neurotransmitter receptors in cortex and hippocampus, consistent with a substantial adaptive reorganization of cortical function. Whether gradual sensory loss affects hippocampal function is unclear. Progressive age-dependent hearing loss (presbycusis) is a risk factor for cognitive decline. Here, we scrutinized C57BL/6 mice that experience hereditary and cumulative deafness starting in young adulthood. We observed that 2–4 months postnatally, increases in the cortical and hippocampal expression of GluN2A and GluN2B subunits of the N-methyl-D-aspartate receptor occurred compared to control mice that lack sensory deficits. Furthermore, GABA and metabotropic glutamate receptor expression were significantly altered. Hippocampal synaptic plasticity was profoundly impaired and mice exhibited significant deficits in spatial memory. These data show that during cortical adaptation to cumulative loss of hearing, plasticity-related neurotransmitter expression is extensively altered in the cortex and hippocampus. Furthermore, cumulative sensory loss compromises hippocampal function.
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Affiliation(s)
- Daniela Beckmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Mirko Feldmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
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2
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Cho KH, Lee SY, Joo K, Rhie DJ. Layer-specific cholinergic modulation of synaptic transmission in layer 2/3 pyramidal neurons of rat visual cortex. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:317-328. [PMID: 31496869 PMCID: PMC6717785 DOI: 10.4196/kjpp.2019.23.5.317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/28/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
It is known that top-down associative inputs terminate on distal apical dendrites in layer 1 while bottom-up sensory inputs terminate on perisomatic dendrites of layer 2/3 pyramidal neurons (L2/3 PyNs) in primary sensory cortex. Since studies on synaptic transmission in layer 1 are sparse, we investigated the basic properties and cholinergic modulation of synaptic transmission in layer 1 and compared them to those in perisomatic dendrites of L2/3 PyNs of rat primary visual cortex. Using extracellular stimulations of layer 1 and layer 4, we evoked excitatory postsynaptic current/potential in synapses in distal apical dendrites (L1-EPSC/L1-EPSP) and those in perisomatic dendrites (L4-EPSC/L4-EPSP), respectively. Kinetics of L1-EPSC was slower than that of L4-EPSC. L1-EPSC showed presynaptic depression while L4-EPSC was facilitating. In contrast, inhibitory postsynaptic currents showed similar paired-pulse ratio between layer 1 and layer 4 stimulations with depression only at 100 Hz. Cholinergic stimulation induced presynaptic depression by activating muscarinic receptors in excitatory and inhibitory synapses to similar extents in both inputs. However, nicotinic stimulation enhanced excitatory synaptic transmission by ~20% in L4-EPSC. Rectification index of AMPA receptors and AMPA/NMDA ratio were similar between synapses in distal apical and perisomatic dendrites. These results provide basic properties and cholinergic modulation of synaptic transmission between distal apical and perisomatic dendrites in L2/3 PyNs of the visual cortex, which might be important for controlling information processing balance depending on attentional state.
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Affiliation(s)
- Kwang-Hyun Cho
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Seul-Yi Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Kayoung Joo
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Duck-Joo Rhie
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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3
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Li DK, Zhang C, Gu Y, Zhang SH, Shi J, Chen XH. The spatial-temporal interaction in the LTP induction between layer IV to layer II/III and layer II/III to layer II/III connections in rats' visual cortex during the development. Neuroscience 2017; 350:39-53. [PMID: 28336410 DOI: 10.1016/j.neuroscience.2017.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 03/09/2017] [Accepted: 03/12/2017] [Indexed: 11/29/2022]
Abstract
During the early developmental period, long-term potentiation (LTP) can be induced in both vertical and horizontal connections in the rat visual cortex. However, the temporal difference in LTP change between the two pathways during animal development remains unclear. In this study, LTP in vertical (from layer IV to layer II/III) and horizontal (from layer II/III to layer II/III) synaptic connections were recorded in brain slices from the same rats, and the developmental changes of LTP in both directions were compared within the animals' eye-opening period. The results showed that the LTP amplitudes declined to unobservable levels on P16 in the horizontal connections and on P20 in the vertical synaptic connections. Meanwhile, V-LTP (LTP induced in the vertical direction) was always stronger than H-LTP (LTP induced in the horizontal direction) under the same conditions of pairing stimulus (PS). Next, H-LTP and V-LTP were induced from the same neuron in layer II/III to determine the spatiotemporal interactions between layer II/III horizontal inputs and ascending synaptic inputs during the maturation of rat visual cortex. The data show that the weak PS, which failed to induce H-LTP alone, was able to induce H-LTP effectively while V-LTP was performed on P10. Our results suggest that V-LTP can strengthen H-LTP induction in the visual cortex during the early developmental period. In contrast, the regulatory effect of H-LTP on V-LTP was much weaker.
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Affiliation(s)
- Da-Ke Li
- Department of Neurology, Huashan Hospital, Fudan University, China
| | - Chao Zhang
- Center for Brain Science Research, School of Life Sciences, Fudan University, China
| | - Yu Gu
- Center for Brain Science Research, School of Life Sciences, Fudan University, China
| | - She-Hong Zhang
- Department of Rehabilitation, Huashan Hospital, Fudan University, China
| | - Jian Shi
- Center for Brain Science Research, School of Life Sciences, Fudan University, China.
| | - Xian-Hua Chen
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, China.
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Age-Dependent Switch of the Role of Serotonergic 5-HT1A Receptors in Gating Long-Term Potentiation in Rat Visual Cortex In Vivo. Neural Plast 2016; 2016:6404082. [PMID: 27247804 PMCID: PMC4877497 DOI: 10.1155/2016/6404082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 11/30/2022] Open
Abstract
The rodent primary visual cortex (V1) is densely innervated by serotonergic axons and previous in vitro work has shown that serotonin (5-HT) can modulate plasticity (e.g., long-term potentiation (LTP)) at V1 synapses. However, little work has examined the effects of 5-HT on LTP under in vivo conditions. We examined the role of 5-HT on LTP in V1 elicited by theta burst stimulation (TBS) of the lateral geniculate nucleus in urethane-anesthetized (adult and juvenile) rats. Thalamic TBS consistently induced potentiation of field postsynaptic potentials (fPSPs) recorded in V1. While 5-HT application (0.1–10 mM) itself did not alter LTP levels, the broad-acting 5-HT receptor antagonists methiothepin (1 mM) resulted in a clear facilitation of LTP in adult animals, an effect that was mimicked by the selective 5-HT1A receptor antagonist WAY 100635 (1 mM). Interestingly, in juvenile rats, WAY 100635 application inhibited LTP, indicative of an age-dependent switch in the role of 5-HT1A receptors in gating V1 plasticity. Analyses of spontaneous electrocorticographic (ECoG) activity in V1 indicated that the antagonist-induced LTP enhancement was not related to systematic changes in oscillatory activity in V1. Together, these data suggest a facilitating role of 5-HT1A receptor activation on LTP in the juvenile V1, which switches to a tonic, inhibitory influence in adulthood.
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5
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Jang HJ, Cho KH, Joo K, Kim MJ, Rhie DJ. Differential modulation of phasic and tonic inhibition underlies serotonergic suppression of long-term potentiation in the rat visual cortex. Neuroscience 2015; 301:351-62. [PMID: 26086544 DOI: 10.1016/j.neuroscience.2015.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/07/2015] [Accepted: 06/09/2015] [Indexed: 01/22/2023]
Abstract
GABA receptor type A (GABA(A)R)-mediated inhibition is divided into phasic and tonic inhibition. GABA(A)Rs mediating the two inhibitory modalities exhibit differences in subcellular localization and subunit composition. We previously demonstrated that phasic and tonic inhibition are independently regulated by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA), respectively. Since modulation of GABA(A)Rs by phosphorylation differs depending on subunit composition and protein kinases, phasic and tonic inhibition might be differentially regulated by a single neuromodulator activating multiple protein kinases. However, the neuromodulatory control for phasic and tonic inhibition is largely unknown. Thus, in the present study, we concurrently investigated the serotonin (5-HT) regulation of phasic and tonic inhibition and its functional implication in the pyramidal neurons of the rat visual cortex. Interestingly, 5-HT enhanced phasic inhibition but suppressed tonic inhibition. Increase in phasic inhibition was mediated by 5-HT2 receptor and CaMKII, whereas decrease in tonic inhibition depended on 5-HT1A receptor and PKA. Thus, phasic and tonic inhibition might be independently regulated even by a single neuromodulator. Functionally, the opposite modulation of phasic and tonic inhibition decreased the summation of consecutive excitatory postsynaptic potentials (EPSPs) without affecting the shape of single EPSPs, which might underlie the suppression of the induction of long-term potentiation by 5-HT. These results suggest that the integrative regulation of phasic and tonic inhibition provides mechanisms for elaborate modulation of shape and summation of EPSPs and long-term synaptic plasticity.
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Affiliation(s)
- H-J Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea; Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - K-H Cho
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - K Joo
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - M-J Kim
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - D-J Rhie
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea; Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
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6
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Lee C, Joo K, Kim MJ, Rhie DJ, Jang HJ. GluN2B-containing N-methyl-D-aspartate receptors compensate for the inhibitory control of synaptic plasticity during the early critical period in the rat visual cortex. J Neurosci Res 2015; 93:1405-12. [PMID: 26013955 DOI: 10.1002/jnr.23604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 11/11/2022]
Abstract
In the visual cortex, synaptic plasticity is very high during the early developmental stage known as the critical period and declines with development after the critical period. Changes in the properties of N-methyl-D-aspartate receptor (NMDAR) and γ-aminobutyric acid type A receptor (GABAA R) have been suggested to underlie the changes in the characteristics of plasticity. However, it is largely unknown how the changes in the two receptors interact to regulate synaptic plasticity. The present study investigates the changes in the properties of NMDAR and GABAA R from 3 to 5 weeks of age in layer 2/3 pyramidal neurons of the rat visual cortex. The impact of these changes on the characteristics of long-term potentiation (LTP) is also investigated. The amplitude and decay time constant of GABAA R-mediated currents increased during this period. However, the decay time constant of NMDAR-mediated currents decreased as a result of the decrease in the proportion of the GluN2B subunit-mediated component. Induction of NMDAR-dependent LTP at 3 weeks depended on the GluN2B subunit, but LTP at 5 weeks did not. Enhancement of GABAA R-mediated inhibition suppressed the induction of LTP only at 5 weeks. However, partial inhibition of the GluN2B subunit with a low concentration of ifenprodil allowed the GABAA R-mediated suppression of LTP at 3 weeks. These results suggest that changes in the properties of NMDAR- and GABAA R-mediated synaptic transmission interact to determine the characteristics of synaptic plasticity during the critical period in the visual cortex.
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Affiliation(s)
- Changik Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kayoung Joo
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Myung-Jun Kim
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Duck-Joo Rhie
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hyun-Jong Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, The Catholic University of Korea, Seoul, Republic of Korea
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7
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Joo K, Yoon SH, Rhie DJ, Jang HJ. Phasic and Tonic Inhibition are Maintained Respectively by CaMKII and PKA in the Rat Visual Cortex. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 18:517-24. [PMID: 25598667 PMCID: PMC4296042 DOI: 10.4196/kjpp.2014.18.6.517] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/16/2014] [Accepted: 10/31/2014] [Indexed: 12/05/2022]
Abstract
Phasic and tonic γ-aminobutyric acidA (GABAA) receptor-mediated inhibition critically regulate neuronal information processing. As these two inhibitory modalities have distinctive features in their receptor composition, subcellular localization of receptors, and the timing of receptor activation, it has been thought that they might exert distinct roles, if not completely separable, in the regulation of neuronal function. Inhibition should be maintained and regulated depending on changes in network activity, since maintenance of excitation-inhibition balance is essential for proper functioning of the nervous system. In the present study, we investigated how phasic and tonic inhibition are maintained and regulated by different signaling cascades. Inhibitory postsynaptic currents were measured as either electrically evoked events or spontaneous events to investigate regulation of phasic inhibition in layer 2/3 pyramidal neurons of the rat visual cortex. Tonic inhibition was assessed as changes in holding currents by the application of the GABAA receptor blocker bicuculline. Basal tone of phasic inhibition was maintained by intracellular Ca2+ and Ca2+/calmodulin-dependent protein kinase II (CaMKII). However, maintenance of tonic inhibition relied on protein kinase A activity. Depolarization of membrane potential (5 min of 0 mV holding) potentiated phasic inhibition via Ca2+ and CaMKII but tonic inhibition was not affected. Thus, phasic and tonic inhibition seem to be independently maintained and regulated by different signaling cascades in the same cell. These results suggest that neuromodulatory signals might differentially regulate phasic and tonic inhibition in response to changes in brain states.
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Affiliation(s)
- Kayoung Joo
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
| | - Shin Hee Yoon
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
| | - Duck-Joo Rhie
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea. ; Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 137-701, Korea
| | - Hyun-Jong Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea. ; Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 137-701, Korea
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8
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Dringenberg HC, Branfield Day LR, Choi DH. Chronic fluoxetine treatment suppresses plasticity (long-term potentiation) in the mature rodent primary auditory cortex in vivo. Neural Plast 2014; 2014:571285. [PMID: 24719772 PMCID: PMC3956292 DOI: 10.1155/2014/571285] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 01/13/2023] Open
Abstract
Several recent studies have provided evidence that chronic treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine can facilitate synaptic plasticity (e.g., ocular dominance shifts) in the adult central nervous system. Here, we assessed whether fluoxetine enhances long-term potentiation (LTP) in the thalamocortical auditory system of mature rats, a developmentally regulated form of plasticity that shows a characteristic decline during postnatal life. Adult rats were chronically treated with fluoxetine (administered in the drinking water, 0.2 mg/mL, four weeks of treatment). Electrophysiological assessments were conducted using an anesthetized (urethane) in vivo preparation, with LTP of field potentials in the primary auditory cortex (A1) induced by theta-burst stimulation of the medial geniculate nucleus. We find that, compared to water-treated control animals, fluoxetine-treated rats did not express higher levels of LTP and, in fact, exhibited reduced levels of potentiation at presumed intracortical A1 synapses. Bioactivity of fluoxetine was confirmed by a reduction of weight gain and fluid intake during the four-week treatment period. We conclude that chronic fluoxetine treatment fails to enhance LTP in the mature rodent thalamocortical auditory system, results that bring into question the notion that SSRIs act as general facilitators of synaptic plasticity in the mammalian forebrain.
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Affiliation(s)
- Hans C. Dringenberg
- Department of Psychology, Queen's University, Kingston, ON, Canada K7L 3N6
- Center for Neuroscience Studies, Queen's University, Kingston, ON, Canada K7L 3N6
| | | | - Deanna H. Choi
- Department of Psychology, Queen's University, Kingston, ON, Canada K7L 3N6
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9
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Gu Y, Huang S, Chang MC, Worley P, Kirkwood A, Quinlan EM. Obligatory role for the immediate early gene NARP in critical period plasticity. Neuron 2013; 79:335-46. [PMID: 23889936 DOI: 10.1016/j.neuron.2013.05.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2013] [Indexed: 11/25/2022]
Abstract
The immediate early gene neuronal activity-regulated pentraxin (NARP) is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) binding protein that is specifically enriched at excitatory synapses onto fast-spiking parvalbumin-positive interneurons (FS [PV] INs). Here, we show that transgenic deletion of NARP decreases the number of excitatory synaptic inputs onto FS (PV) INs and reduces net excitatory synaptic drive onto FS (PV) INs. Accordingly, the visual cortex of NARP(-/-) mice is hyperexcitable and unable to express ocular dominance plasticity, although many aspects of visual function are unimpaired. Importantly, the number and strength of inhibitory synaptic contacts from FS (PV) INs onto principle neurons in the visual cortex is normal in NARP(-/-) mice, and enhancement of this output recovers the expression of experience-dependent synaptic plasticity. Thus the recruitment of inhibition from FS (PV) INs plays a central role in enabling the critical period for ocular dominance plasticity.
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Affiliation(s)
- Yu Gu
- Neuroscience and Cognitive Sciences Program, University of Maryland, College Park, MD 20742, USA
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10
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Liu Y, Shi X, Li Y, Zhao K. The influences of dark rearing on the transmission characteristics of layer II/III pyramidal cells during the critical period. Brain Res 2012; 1457:26-32. [PMID: 22534484 DOI: 10.1016/j.brainres.2012.03.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 02/19/2012] [Accepted: 03/27/2012] [Indexed: 11/25/2022]
Abstract
The characteristics of synaptic plasticity on layer II/III pyramidal cells in different ages of rats have been studied extensively, and dark rearing is one of the important impact factors. To systematically analyze the influence of dark rearing on synaptic plasticity during the critical period of visual development, we studied the characteristics of short-term and long-term synaptic plasticities of layer II/III pyramidal cells of rats in three rearing conditions during P14 to P37. The paired-pulse ratio (PPR) of inhibitory postsynaptic currents (IPSCs) of layer II/III pyramidal cells was effected by both ages and rearing conditions, but the PPR of excitatory postsynaptic currents (EPSCs) did not change obviously. Moreover, long-term synaptic plasticity of rats in the dark rearing condition did not significantly change with age, while it was elevated during P16 and P21 for rats in the normal rearing condition. These results suggest that visual experience can affect the characteristics of short-term and long-term synaptic plasticities. The IPSC/EPSC ratio increased gradually with aging for NR rats, but the ratio slightly decreased for DR rats, which indicates the relative increase of inhibitory components during the critical period of visual development. The characteristics during P35 and P37 of the 30-day dark-reared (30D×N) group had similar trends with the normal-reared rats during P16 and P21, which emphasizes that dark rearing can postpone the timing of the critical period.
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Affiliation(s)
- Yuyan Liu
- Tianjin Medical University, Tianjin, 300070, China
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Park SW, Jang HJ, Cho KH, Kim MJ, Yoon SH, Rhie DJ. Developmental Switch of the Serotonergic Role in the Induction of Synaptic Long-term Potentiation in the Rat Visual Cortex. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2012; 16:65-70. [PMID: 22416222 PMCID: PMC3298828 DOI: 10.4196/kjpp.2012.16.1.65] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/08/2012] [Accepted: 02/16/2012] [Indexed: 11/15/2022]
Abstract
Synaptic long-term potentiation (LTP) and long-term depression (LTD) have been studied as mechanisms of ocular dominance plasticity in the rat visual cortex. Serotonin (5-hydroxytryptamine, 5-HT) inhibits the induction of LTP and LTD during the critical period of the rat visual cortex (postnatal 3~5 weeks). However, in adult rats, the increase in 5-HT level in the brain by the administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine reinstates ocular dominance plasticity and LTP in the visual cortex. Here, we investigated the effect of 5-HT on the induction of LTP in the visual cortex obtained from 3- to 10-week-old rats. Field potentials in layer 2/3, evoked by the stimulation of underlying layer 4, was potentiated by theta-burst stimulation (TBS) in 3- and 5-week-old rats, then declined to the baseline level with aging to 10 weeks. Whereas 5-HT inhibited the induction of LTP in 5-week-old rats, it reinstated the induction of N-methyl-D-aspartate receptor (NMDA)-dependent LTP in 8- and 10-week-old rats. Moreover, the selective SSRI citalopram reinstated LTP. The potentiating effect of 5-HT at 8 weeks of age was mediated by the activation of 5-HT2 receptors, but not by the activation of either 5-HT1A or 5-HT3 receptors. These results suggested that the effect of 5-HT on the induction of LTP switches from inhibitory in young rats to facilitatory in adult rats.
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Affiliation(s)
- Sung-Won Park
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
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12
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Jang HJ, Cho KH, Park SW, Kim MJ, Yoon SH, Rhie DJ. Layer-specific serotonergic facilitation of IPSC in layer 2/3 pyramidal neurons of the visual cortex. J Neurophysiol 2011; 107:407-16. [PMID: 22013240 DOI: 10.1152/jn.00535.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) inhibits the induction of long-term synaptic plasticity in layer 2/3 of the visual cortex at the end of its critical period in rats. However, the cellular and molecular mechanisms remain unclear. Since inhibitory influence is crucial in the induction of synaptic plasticity, the effect of 5-HT on inhibitory transmission was investigated in layer 2/3 pyramidal neurons of the primary visual cortex. The amplitude of inhibitory postsynaptic current (IPSC), but not excitatory postsynaptic current, evoked by stimulation of the underlying layer 4, was increased by ∼20% with a bath application of 5-HT. The amplitude of miniature IPSC was also increased by the application of 5-HT, while the paired-pulse ratio was not changed. The facilitating effect of 5-HT on IPSC was mediated by the activation of 5-HT(2) receptors. An increase in intracellular Ca(2+) via release from inositol 1,4,5-trisphosphate (IP(3))-sensitive stores, which was confirmed by confocal Ca(2+) imaging, and activation of Ca(2+)/calmodulin-dependent kinase II (CaMKII) were involved in the facilitation of IPSC by 5-HT. However, 5-HT failed to facilitate IPSC evoked by the stimulation of layer 1. These results suggest that activation of 5-HT(2) receptors releases intracellular Ca(2+) via IP(3)-sensitive stores, which facilitates GABA(A)ergic transmission via the activation of CaMKII in layer 2/3 pyramidal neurons of the visual cortex in a layer-specific manner. Thus facilitation of inhibitory transmission by 5-HT might be involved in regulating the information flow and the induction of long-term synaptic plasticity, in a pathway-specific manner.
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Affiliation(s)
- Hyun-Jong Jang
- Dept. of Physiology, College of Medicine, Catholic Univ. of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Republic of Korea
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13
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Tchekalarova J, Kubová H, Mareš P. Transient changes of cortical interhemispheric responses after repeated caffeine administration in immature rats. Physiol Res 2011; 60:961-9. [PMID: 21995906 DOI: 10.33549/physiolres.932147] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Repeated postnatal caffeine treatment of rat pups led to transient developmental changes in cortical epileptic afterdischarges. To know if physiological cortical functions are also affected transcallosal evoked potentials were studied. Rat pups of the Wistar strain were injected daily with caffeine (10 or 20 mg/kg s.c.) from postnatal day (P) 7 to P11, control siblings received saline. Cortical interhemispheric responses were tested at P12, 18, 25 and in young adult rats. Amplitude of initial monosynaptic components was evaluated in averaged responses. Single pulses as well as paired and frequency (five pulses) stimulations were used. Developmental rules - highest amplitude of responses in 25-day-old rats, potentiation with paired and frequency stimulation present since P18 - were confirmed. Caffeine-treated rats exhibited transient changes: single responses were augmented in P25 if high stimulation intensity was used, paired-pulse and frequency responses were higher in experimental than in control animals at P12, the opposite change was observed in 18- and more markedly in 25-day-old rats. No significant changes were found in adult animals, monosynaptic transcallosal responses represent a simple and robust system. The developmental profile of described changes did not exactly correspond to changes in epileptic afterdischarges supporting the possibility that afterdischarges did not arise from early monosynaptic components of responses. In spite of transient nature of changes they can reflect delayed or more probably modified brain development.
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Affiliation(s)
- J Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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14
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A refractory period for rejuvenating GABAergic synaptic transmission and ocular dominance plasticity with dark exposure. J Neurosci 2011; 30:16636-42. [PMID: 21148002 DOI: 10.1523/jneurosci.4384-10.2010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dark exposure initiated in adulthood reactivates robust ocular dominance plasticity in the visual cortex. Here, we show that a critical component of the response to dark exposure is the rejuvenation of inhibitory synaptic transmission, resulting in a decrease in functional inhibitory synaptic density, a decrease in paired-pulse depression, and a reexpression of endocannabinoid-dependent inhibitory long-term depression (iLTD). Importantly, pharmacological acceleration of the maturation of inhibition in dark-exposed adults inhibits the reexpression of iLTD and the reactivation of ocular dominance plasticity. Surprisingly, dark exposure initiated earlier in postnatal development does not rejuvenate inhibitory synaptic transmission or facilitate rapid ocular dominance plasticity, demonstrating the presence of a refractory period for the regulation of synaptic plasticity by visual deprivation.
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15
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Jang HJ, Cho KH, Park SW, Kim MJ, Yoon SH, Rhie DJ. The development of phasic and tonic inhibition in the rat visual cortex. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2010; 14:399-405. [PMID: 21311681 DOI: 10.4196/kjpp.2010.14.6.399] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 11/08/2010] [Accepted: 11/09/2010] [Indexed: 11/15/2022]
Abstract
Gamma-aminobutyric acid (GABA)-ergic inhibition is important in the function of the visual cortex. In a previous study, we reported a developmental increase in GABA(A) receptor-mediated inhibition in the rat visual cortex from 3 to 5 weeks of age. Because this developmental increase is crucial to the regulation of the induction of long-term synaptic plasticity, in the present study we investigated in detail the postnatal development of phasic and tonic inhibition. The amplitude of phasic inhibition evoked by electrical stimulation increased during development from 3 to 8 weeks of age, and the peak time and decay kinetics of inhibitory postsynaptic potential (IPSP) and current (IPSC) slowed progressively. Since the membrane time constant decreased during this period, passive membrane properties might not be involved in the kinetic changes of IPSP and IPSC. Tonic inhibition, another mode of GABA(A) receptor-mediated inhibition, also increased developmentally and reached a plateau at 5 weeks of age. These results indicate that the time course of the postnatal development of GABAergic inhibition matched well that of the functional maturation of the visual cortex. Thus, the present study provides significant insight into the roles of inhibitory development in the functional maturation of the visual cortical circuits.
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Affiliation(s)
- Hyun-Jong Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
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16
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Jang HJ, Cho KH, Park SW, Kim MJ, Yoon SH, Rhie DJ. Effects of Serotonin on the Induction of Long-term Depression in the Rat Visual Cortex. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2010; 14:337-43. [PMID: 21165334 DOI: 10.4196/kjpp.2010.14.5.337] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 10/11/2010] [Accepted: 10/18/2010] [Indexed: 11/15/2022]
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) have both been studied as mechanisms of ocular dominance plasticity in the rat visual cortex. In a previous study, we suggested that a developmental increase in serotonin [5-hydroxytryptamine (5-HT)] might be involved in the decline of LTP, since 5-HT inhibited its induction. In the present study, to further understand the role of 5-HT in a developmental decrease in plasticity, we investigated the effect of 5-HT on the induction of LTD in the pathway from layer 4 to layer 2/3. LTD was inhibited by 5-HT (10 µM) in 5-week-old rats. The inhibitory effect was mediated by activation of 5-HT(2) receptors. Since 5-HT also regulates the development of visual cortical circuits, we also investigated the role of 5-HT on the development of inhibition. The development of inhibition was retarded by chronic (2 weeks) depletion of endogenous 5-HT in 5-week-old rats, in which LTD was reinstated. These results suggest that 5-HT regulates the induction of LTD directly via activation of 5-HT(2) receptors and indirectly by regulating cortical development. Thus, the present study provides significant insight into the roles of 5-HT on the development of visual cortical circuits and on the age-dependent decline of long-term synaptic plasticity.
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Affiliation(s)
- Hyun-Jong Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
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Hager AM, Dringenberg HC. Assessment of different induction protocols to elicit long-term depression (LTD) in the rat visual cortex in vivo. Brain Res 2010; 1318:33-41. [DOI: 10.1016/j.brainres.2009.12.063] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 10/20/2022]
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18
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Hogsden JL, Dringenberg HC. Decline of long-term potentiation (LTP) in the rat auditory cortex in vivo during postnatal life: Involvement of NR2B subunits. Brain Res 2009; 1283:25-33. [DOI: 10.1016/j.brainres.2009.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 05/27/2009] [Accepted: 06/03/2009] [Indexed: 11/28/2022]
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