1
|
Kida H, Toyoshima S, Kawakami R, Sakimoto Y, Mitsushima D. Properties of layer V pyramidal neurons in the primary motor cortex that represent acquired motor skills. Neuroscience 2024; 559:54-63. [PMID: 39209105 DOI: 10.1016/j.neuroscience.2024.08.033] [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: 03/11/2024] [Revised: 08/19/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024]
Abstract
Layer V neurons in primary motor cortex (M1) are required for motor skill learning. We analyzed training-induced plasticity using a whole-cell slice patch-clamp technique with a rotor rod task, and found that training induces diverse changes in intrinsic properties and synaptic plasticity in M1 layer V neurons. Although the causal relationship between specific cellular changes and motor performance is unclear, by linking individual motor performance to cellular/synaptic functions, we identified several cellular and synaptic parameters that represent acquired motor skills. With respect to cellular properties, motor performance was positively correlated with resting membrane potential and fast afterhyperpolarization, but not with the membrane resistance, capacitance, or threshold. With respect to synaptic function, the performance was positively correlated with AMPA receptor-mediated postsynaptic currents, but not with GABAA receptor-mediated postsynaptic currents. With respect to live imaging analysis in Thy1-YFP mice, we further demonstrated a cross-correlation between motor performance, spine head volume, and self-entropy per spine. In the present study, we identified several changes in M1 layer V pyramidal neurons after motor training that represent acquired motor skills. Furthermore, training increased extracellular acetylcholine levels known to promote synaptic plasticity, which is correlated with individual motor performance. These results suggest that systematic control of specific intracellular parameters and enhancement of synaptic plasticity in M1 layer V neurons may be useful for improving motor skills.
Collapse
Affiliation(s)
- H Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan.
| | - S Toyoshima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - R Kawakami
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime 791-0295, Japan
| | - Y Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - D Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan.
| |
Collapse
|
2
|
Yang Y, Sakimoto Y, Mitsushima D. Postnatal Development of Synaptic Plasticity at Hippocampal CA1 Synapses: Correlation of Learning Performance with Pathway-Specific Plasticity. Brain Sci 2024; 14:382. [PMID: 38672030 PMCID: PMC11048295 DOI: 10.3390/brainsci14040382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/05/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
To determine the critical timing for learning and the associated synaptic plasticity, we analyzed developmental changes in learning together with training-induced plasticity. Rats were subjected to an inhibitory avoidance (IA) task prior to weaning. While IA training did not alter latency at postnatal day (PN) 16, there was a significant increase in latency from PN 17, indicating a critical day for IA learning between PN 16 and 17. One hour after training, acute hippocampal slices were prepared for whole-cell patch clamp analysis following the retrieval test. In the presence of tetrodotoxin (0.5 µM), miniature excitatory postsynaptic currents (mEPSCs) and inhibitory postsynaptic currents (mIPSCs) were sequentially recorded from the same CA1 neuron. Although no changes in the amplitude of mEPSCs or mIPSCs were observed at PN 16 and 21, significant increases in both excitatory and inhibitory currents were observed at PN 23, suggesting a specific critical day for training-induced plasticity between PN 21 and 23. Training also increased the diversity of postsynaptic currents at PN 23 but not at PN 16 and 21, demonstrating a critical day for training-induced increase in the information entropy of CA1 neurons. Finally, we analyzed the plasticity at entorhinal cortex layer III (ECIII)-CA1 or CA3-CA1 synapses for each individual rat. At either ECIII-CA1 or CA3-CA1 synapses, a significant correlation between mean α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartic acid (AMPA/NMDA) ratio and learning outcomes emerged at PN 23 at both synapses, demonstrating a critical timing for the direct link between AMPA receptor-mediated synaptic plasticity and learning efficacy. Here, we identified multiple critical periods with respect to training-induced synaptic plasticity and delineated developmental trajectories of learning mechanisms at hippocampal CA1 synapses.
Collapse
Affiliation(s)
- Yuheng Yang
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
- The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan
| |
Collapse
|
3
|
Zhang R, Tao X, Sun R, Dai T, Xi X, Sun W, Song L, Gong W. Cognitive-exercise dual-task promotes cognitive function recovery in chronic cerebral ischemia male rats through regulating PI3K/Akt signaling pathway via inhibition of EphrinA3/EphA4. J Neurosci Res 2024; 102. [PMID: 38284844 DOI: 10.1002/jnr.25275] [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: 08/14/2023] [Revised: 10/23/2023] [Accepted: 10/29/2023] [Indexed: 01/30/2024]
Abstract
Chronic cerebral ischemia (CCI) can lead to vascular cognitive impairment, but therapeutic options are limited. Cognitive-exercise dual-task (CEDT), as a potential rehabilitation intervention, can attenuate cognitive impairment. However, the related mechanisms remain unclear. In this study, 2-vessel occlusion (2-VO) in male SD rats was performed to establish the CCI model. The rats were treated with cognitive, exercise, or CEDT intervention for 21 days. The Morris water maze (MWM) test was used to assess cognitive ability. TUNEL staining was used to detect the neuronal apoptosis. Immunofluorescence, RT-qPCR and Western blot were used to detect the protein or mRNA levels of EphrinA3, EphA4, p-PI3K, and p-Akt. The results showed that CEDT could improve performance in the MWM test, reverse the increased expression of EphrinA3 and EphA4, and the reduced expression of p-PI3K and p-Akt in CCI rats, which was superior to exercise and cognitive interventions. In vitro, oxygenglucose deprivation (OGD) challenge of astrocytes and neuronal cells were used to mimic cerebral ischemia. Immunofluorescence assay revealed that the levels of MAP-2, p-PI3K, and p-Akt were reduced in EphrinA3 overexpressed cells after OGD stimulation. Finally, the knock-down of EphrinA3 by shRNA significantly promoted the recovery of cognitive function and activation of PI3K/Akt after CEDT treatment in CCI rats. In conclusion, our study suggests that CEDT promotes cognitive function recovery after CCI by regulating the signaling axis of EphrinA3/EphA4/PI3K/Akt.
Collapse
Affiliation(s)
- Rong Zhang
- Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
- Beijing Rehabilitation Medicine Academy, Capital Medical University, Beijing, China
- The Second Clinical Medical College, Yunnan University of Chinese Medicine, Kunming, China
| | - Xue Tao
- Department of Research, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Ruifeng Sun
- Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
- Beijing Rehabilitation Medicine Academy, Capital Medical University, Beijing, China
| | - Tengteng Dai
- The Second Clinical Medical College, Yunnan University of Chinese Medicine, Kunming, China
| | - XiaoShuang Xi
- Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
- Beijing Rehabilitation Medicine Academy, Capital Medical University, Beijing, China
| | - Weishuang Sun
- Rehabilitation Medicine Academy, Weifang Medical University, Weifang, China
| | - Li Song
- Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
- Beijing Rehabilitation Medicine Academy, Capital Medical University, Beijing, China
| | - Weijun Gong
- Department of Neurological Rehabilitation, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
4
|
Kida H, Kawakami R, Sakai K, Otaku H, Imamura K, Han TZ, Sakimoto Y, Mitsushima D. Motor training promotes both synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex. J Physiol 2023; 601:335-353. [PMID: 36515167 DOI: 10.1113/jp283755] [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: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 12/15/2022] Open
Abstract
Layer V neurons in the primary motor cortex (M1) are important for motor skill learning. Since pretreatment of either CNQX or APV in rat M1 layer V impaired rotor rod learning, we analysed training-induced synaptic plasticity by whole-cell patch-clamp technique in acute brain slices. Rats trained for 1 day showed a decrease in small inhibitory postsynaptic current (mIPSC) frequency and an increase in the paired-pulse ratio of evoked IPSCs, suggesting a transient decrease in presynaptic GABA release in the early phase. Rats trained for 2 days showed an increase in miniature excitatory postsynaptic current (mEPSC) amplitudes/frequency and elevated AMPA/NMDA ratios, suggesting a long-term strengthening of AMPA receptor-mediated excitatory synapses. Importantly, rotor rod performance in trained rats was correlated with the mean mEPSC amplitude and the frequency obtained from that animal. In current-clamp analysis, 1-day-trained rats transiently decreased the current-induced firing rate, while 2-day-trained rats returned to pre-training levels, suggesting dynamic changes in intrinsic properties. Furthermore, western blot analysis of layer V detected decreased phosphorylation of Ser408-409 in GABAA receptor β3 subunits in 1-day-trained rats, and increased phosphorylation of Ser831 in AMPA receptor GluA1 subunits in 2-day-trained rats. Finally, live-imaging analysis of Thy1-YFP transgenic mice showed that the training rapidly recruited a substantial number of spines for long-term plasticity in M1 layer V neurons. Taken together, these results indicate that motor training induces complex and diverse plasticity in M1 layer V pyramidal neurons. KEY POINTS: Here we examined motor training-induced synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex. The training reduced presynaptic GABA release in the early phase, but strengthened AMPA receptor-mediated excitatory synapses in the later phase: acquired motor performance after training correlated with the strength of excitatory synapses rather than inhibitory synapses. As to the intrinsic property, the training transiently decreased the firing rate in the early phase, but returned to pre-training levels in the later phase. Western blot analysis detected decreased phosphorylation of Ser408-409 in GABAA receptor β3 subunits in the acute phase, and increased phosphorylation of Ser831 in AMPA receptor GluA1 subunits in the later phase. Live-imaging analysis of Thy1-YFP transgenic mice showed rapid and long-term spine plasticity in M1 layer V neurons, suggesting training-induced increases in self-entropy per spine.
Collapse
Affiliation(s)
- H Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - R Kawakami
- Department of Molecular Medicine for Pathogenesis, Graduate School of Medicine, Ehime University, Ehime, Japan
| | - K Sakai
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - H Otaku
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - K Imamura
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Thiri-Zin Han
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Y Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.,The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, Japan
| |
Collapse
|
5
|
Sakimoto Y, Shintani A, Yoshiura D, Goshima M, Kida H, Mitsushima D. A critical period for learning and plastic changes at hippocampal CA1 synapses. Sci Rep 2022; 12:7199. [PMID: 35504922 PMCID: PMC9065057 DOI: 10.1038/s41598-022-10453-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/24/2022] [Indexed: 02/07/2023] Open
Abstract
Postnatal development of hippocampal function has been reported in many mammalian species, including humans. To obtain synaptic evidence, we analyzed developmental changes in plasticity after an inhibitory avoidance task in rats. Learning performance was low in infants (postnatal 2 weeks) but clearly improved from the juvenile period (3-4 weeks) to adulthood (8 weeks). One hour after the training, we prepared brain slices and sequentially recorded miniature excitatory postsynaptic currents (mEPSCs) and inhibitory postsynaptic currents (mIPSCs) from the same hippocampal CA1 neuron. Although the training failed to affect the amplitude of either mEPSCs or mIPSCs at 2 weeks, it increased mEPSC, but not mIPSC, amplitude at 3 weeks. At 4 weeks, the training had increased the amplitude of both mEPSCs and mIPSCs, whereas mIPSC, but not mEPSC, amplitude was increased at 8 weeks. Because early-life physiological functions can affect performance, we also evaluated sensory-motor functions together with emotional state and found adequate sensory/motor functions from infancy to adulthood. Moreover, by analyzing performance of rats in multiple hippocampal-dependent tasks, we found that the developmental changes in the performance are task dependent. Taken together, these findings delineate a critical period for learning and plastic changes at hippocampal CA1 synapses.
Collapse
Affiliation(s)
- Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan.
| | - Ako Shintani
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Daiki Yoshiura
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Makoto Goshima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan.
- The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, 753-8511, Japan.
| |
Collapse
|
6
|
Longatti A, Ponzoni L, Moretto E, Giansante G, Lattuada N, Colombo MN, Francolini M, Sala M, Murru L, Passafaro M. Arhgap22 Disruption Leads to RAC1 Hyperactivity Affecting Hippocampal Glutamatergic Synapses and Cognition in Mice. Mol Neurobiol 2021; 58:6092-6110. [PMID: 34455539 PMCID: PMC8639580 DOI: 10.1007/s12035-021-02502-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 07/15/2021] [Indexed: 11/03/2022]
Abstract
Rho GTPases are a class of G-proteins involved in several aspects of cellular biology, including the regulation of actin cytoskeleton. The most studied members of this family are RHOA and RAC1 that act in concert to regulate actin dynamics. Recently, Rho GTPases gained much attention as synaptic regulators in the mammalian central nervous system (CNS). In this context, ARHGAP22 protein has been previously shown to specifically inhibit RAC1 activity thus standing as critical cytoskeleton regulator in cancer cell models; however, whether this function is maintained in neurons in the CNS is unknown. Here, we generated a knockout animal model for arhgap22 and provided evidence of its role in the hippocampus. Specifically, we found that ARHGAP22 absence leads to RAC1 hyperactivity and to an increase in dendritic spine density with defects in synaptic structure, molecular composition, and plasticity. Furthermore, arhgap22 silencing causes impairment in cognition and a reduction in anxiety-like behavior in mice. We also found that inhibiting RAC1 restored synaptic plasticity in ARHGAP22 KO mice. All together, these results shed light on the specific role of ARHGAP22 in hippocampal excitatory synapse formation and function as well as in learning and memory behaviors.
Collapse
Affiliation(s)
- Anna Longatti
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi Di Milano, 20133, Milan, Italy
| | | | - Edoardo Moretto
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Giorgia Giansante
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Norma Lattuada
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Maria Nicol Colombo
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Mariaelvina Sala
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Luca Murru
- Institute of Neuroscience, CNR, Milan, 20129, Italy.
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy.
| | - Maria Passafaro
- Institute of Neuroscience, CNR, Milan, 20129, Italy.
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy.
| |
Collapse
|
7
|
Significance of GABA A Receptor for Cognitive Function and Hippocampal Pathology. Int J Mol Sci 2021; 22:ijms222212456. [PMID: 34830337 PMCID: PMC8623595 DOI: 10.3390/ijms222212456] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 02/05/2023] Open
Abstract
The hippocampus is a primary area for contextual memory, known to process spatiotemporal information within a specific episode. Long-term strengthening of glutamatergic transmission is a mechanism of contextual learning in the dorsal cornu ammonis 1 (CA1) area of the hippocampus. CA1-specific immobilization or blockade of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor delivery can impair learning performance, indicating a causal relationship between learning and receptor delivery into the synapse. Moreover, contextual learning also strengthens GABAA (gamma-aminobutyric acid) receptor-mediated inhibitory synapses onto CA1 neurons. Recently we revealed that strengthening of GABAA receptor-mediated inhibitory synapses preceded excitatory synaptic plasticity after contextual learning, resulting in a reduced synaptic excitatory/inhibitory (E/I) input balance that returned to pretraining levels within 10 min. The faster plasticity at inhibitory synapses may allow encoding a contextual memory and prevent cognitive dysfunction in various hippocampal pathologies. In this review, we focus on the dynamic changes of GABAA receptor mediated-synaptic currents after contextual learning and the intracellular mechanism underlying rapid inhibitory synaptic plasticity. In addition, we discuss that several pathologies, such as Alzheimer’s disease, autism spectrum disorders and epilepsy are characterized by alterations in GABAA receptor trafficking, synaptic E/I imbalance and neuronal excitability.
Collapse
|
8
|
Molina SJ, Lietti ÁE, Carreira Caro CS, Buján GE, Guelman LR. Effects of early noise exposure on hippocampal-dependent behaviors during adolescence in male rats: influence of different housing conditions. Anim Cogn 2021; 25:103-120. [PMID: 34322771 DOI: 10.1007/s10071-021-01540-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 10/20/2022]
Abstract
Central nervous system (CNS) development is a very complex process that can be altered by environmental stimuli such as noise, which can generate long-term auditory and/or extra-auditory impairments. We have previously reported that early noise exposure can induce hippocampus-related behavioral alterations in postnatal day (PND) 28 adolescent rats. Furthermore, we recently found biochemical modifications in the hippocampus (HC) of these animals that seemed to endure even in more mature animals (i.e. PND35) and that have not been studied along with behavioral correlates. Thus, the aim of this work was to reveal novel data about the effects of early noise exposure on hippocampal-dependent behaviors in more mature animals. Additionally, extended enriched environment (EE) housing was evaluated to determine its capacity to induce behavioral modifications, either by its neuroprotective ability or the greater stimulation that it generates. Male Wistar rats were exposed to different noise schemes at PND7 or PND15. Upon weaning, some animals were transferred to EE whereas others were kept in standard cages. At PND35, different hippocampal-dependent behavioral assessments were performed. Results showed noise-induced behavioral changes that differed according to the scheme and age of exposure used. In addition, housing in an EE was effective either in preventing some of these changes or in inducing the appearance of new behavioral modifications. These findings suggest that CNS development would be sensitive to the effects of different type of environmental stimuli such as noise or enriched housing, leading to maladaptive behavioral changes that last even until adolescence.
Collapse
Affiliation(s)
- Sonia Jazmín Molina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Facultad de Medicina, Paraguay 2155, Piso 15, 1121, Buenos Aires, Argentina.
| | - Ángel Emanuel Lietti
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Facultad de Medicina, Paraguay 2155, Piso 15, 1121, Buenos Aires, Argentina
| | - Candela Sofía Carreira Caro
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Facultad de Medicina, Paraguay 2155, Piso 15, 1121, Buenos Aires, Argentina
| | - Gustavo Ezequiel Buján
- Universidad de Buenos Aires, Facultad de Medicina, 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| | - Laura Ruth Guelman
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Facultad de Medicina, Paraguay 2155, Piso 15, 1121, Buenos Aires, Argentina.,Universidad de Buenos Aires, Facultad de Medicina, 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| |
Collapse
|
9
|
Androgen Affects the Inhibitory Avoidance Memory by Primarily Acting on Androgen Receptor in the Brain in Adolescent Male Rats. Brain Sci 2021; 11:brainsci11020239. [PMID: 33672867 PMCID: PMC7918178 DOI: 10.3390/brainsci11020239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 11/17/2022] Open
Abstract
Adolescence is the critical postnatal stage for the action of androgen in multiple brain regions. Androgens can regulate the learning/memory functions in the brain. It is known that the inhibitory avoidance test can evaluate emotional memory and is believed to be dependent largely on the amygdala and hippocampus. However, the effects of androgen on inhibitory avoidance memory have never been reported in adolescent male rats. In the present study, the effects of androgen on inhibitory avoidance memory and on androgen receptor (AR)-immunoreactivity in the amygdala and hippocampus were studied using behavioral analysis, Western blotting and immunohistochemistry in sham-operated, orchiectomized, orchiectomized + testosterone or orchiectomized + dihydrotestosterone-administered male adolescent rats. Orchiectomized rats showed significantly reduced time spent in the illuminated box after 30 min (test 1) or 24 h (test 2) of electrical foot-shock (training) and reduced AR-immunoreactivity in amygdala/hippocampal cornu Ammonis (CA1) in comparison to those in sham-operated rats. Treatment of orchiectomized rats with either non-aromatizable dihydrotestosterone or aromatizable testosterone were successfully reinstated these effects. Application of flutamide (AR-antagonist) in intact adolescent rats exhibited identical changes to those in orchiectomized rats. These suggest that androgens enhance the inhibitory avoidance memory plausibly by binding with AR in the amygdala and hippocampus.
Collapse
|
10
|
Islam MN, Sakimoto Y, Jahan MR, Ishida M, Tarif AMM, Nozaki K, Masumoto KH, Yanai A, Mitsushima D, Shinoda K. Androgen Affects the Dynamics of Intrinsic Plasticity of Pyramidal Neurons in the CA1 Hippocampal Subfield in Adolescent Male Rats. Neuroscience 2020; 440:15-29. [PMID: 32450298 DOI: 10.1016/j.neuroscience.2020.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/18/2022]
Abstract
Androgen receptor (AR) is abundantly expressed in the preoptico-hypothalamic area, bed nucleus of stria terminalis, and medial amygdala of the brain where androgen plays an important role in regulating male sociosexual, emotional and aggressive behaviors. In addition to these brain regions, AR is also highly expressed in the hippocampus, suggesting that the hippocampus is another major target of androgenic modulation. It is known that androgen can modulate synaptic plasticity in the CA1 hippocampal subfield. However, to date, the effects of androgen on the intrinsic plasticity of hippocampal neurons have not been clearly elucidated. In this study, the effects of androgen on the expression of AR in the hippocampus and on the dynamics of intrinsic plasticity of CA1 pyramidal neurons were examined using immunohistochemistry, Western blotting and whole-cell current-clamp recording in unoperated, sham-operated, orchiectomized (OCX), OCX + testosterone (T) or OCX + dihydrotestosterone (DHT)-primed adolescent male rats. Orchiectomy significantly decreased AR-immunoreactivity, resting membrane potential, action potential numbers, afterhyperpolarization amplitude and membrane resistance, whereas it significantly increased action potential threshold and membrane capacitance. These effects were successfully reversed by treatment with either aromatizable androgen T or non-aromatizable androgen DHT. Furthermore, administration of the AR-antagonist flutamide in intact rats showed similar changes to those in OCX rats, suggesting that androgens affect the excitability of CA1 pyramidal neurons possibly by acting on the AR. Our current study potentially clarifies the role of androgen in enhancing the basal excitability of the CA1 pyramidal neurons, which may influence selective neuronal excitation/activation to modulate certain hippocampal functions.
Collapse
Affiliation(s)
- Md Nabiul Islam
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Mir Rubayet Jahan
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan; Department of Anatomy and Histology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Mako Ishida
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Abu Md Mamun Tarif
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Kanako Nozaki
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Koh-Hei Masumoto
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Akie Yanai
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan; Department of Basic Laboratory Sciences, Faculty of Medicine and Health Sciences, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan
| | - Koh Shinoda
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan.
| |
Collapse
|
11
|
Paw-Min-Thein-Oo, Sakimoto Y, Kida H, Mitsushima D. Proximodistal Heterogeneity in Learning-promoted Pathway-specific Plasticity at Dorsal CA1 Synapses. Neuroscience 2020; 437:184-195. [PMID: 32360699 DOI: 10.1016/j.neuroscience.2020.04.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 01/28/2023]
Abstract
Contextual learning requires the delivery of AMPA receptors to CA1 synapses in the dorsal hippocampus. However, proximodistal heterogeneity of pathway-specific plasticity remains unclear. Here, we examined the proximodistal heterogeneity in learning-induced plasticity at the CA1 synapses with inputs from the entorhinal cortex layer III (ECIII) or from CA3. We subjected male rats to an inhibitory avoidance task and prepared acute hippocampal slices for whole-cell patch clamp experiments, where we stimulated ECIII-CA1 or CA3-CA1 input fibers to analyze evoked excitatory postsynaptic currents (EPSCs). Compared to untrained controls, trained rats exhibited higher AMPA/NMDA current ratios at CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons, which suggested that region-specific plasticity occurred after learning. Moreover, trained rats exhibited higher AMPA/NMDA current ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons. These findings suggested the presence of proximodistal heterogeneity in pathway-specific postsynaptic plasticity. Regarding presynaptic plasticity, training slightly, but significantly increased the paired-pulse ratios of CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons. Moreover, trained rats exhibited higher paired-pulse ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons, which suggested region-specific presynaptic plasticity. Finally, learning was clearly prevented by the bilateral microinjection of a plasticity blocker in the proximal or intermediate, but not distal CA1 subfields, which suggested functional heterogeneity along the proximodistal axis. Understanding region- and pathway-specific plasticity at dorsal CA1 synapses could aid in controlling encoded memory.
Collapse
Affiliation(s)
- Paw-Min-Thein-Oo
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan.
| |
Collapse
|
12
|
Bilz F, Geurten BRH, Hancock CE, Widmann A, Fiala A. Visualization of a Distributed Synaptic Memory Code in the Drosophila Brain. Neuron 2020; 106:963-976.e4. [PMID: 32268119 DOI: 10.1016/j.neuron.2020.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 11/19/2019] [Accepted: 03/13/2020] [Indexed: 10/24/2022]
Abstract
During associative conditioning, animals learn which sensory cues are predictive for positive or negative conditions. Because sensory cues are encoded by distributed neurons, one has to monitor plasticity across many synapses to capture how learned information is encoded. We analyzed synaptic boutons of Kenyon cells of the Drosophila mushroom body γ lobe, a brain structure that mediates olfactory learning. A fluorescent Ca2+ sensor was expressed in single Kenyon cells so that axonal boutons could be assigned to distinct cells and Ca2+ could be measured across many animals. Learning induced directed synaptic plasticity in specific compartments along the axons. Moreover, we show that odor-evoked Ca2+ dynamics across boutons decorrelate as a result of associative learning. Information theory indicates that learning renders the stimulus representation more distinct compared with naive stimuli. These data reveal that synaptic boutons rather than cells act as individually modifiable units, and coherence among them is a memory-encoding parameter.
Collapse
Affiliation(s)
- Florian Bilz
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Bart R H Geurten
- Department of Cellular Neurobiology, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Clare E Hancock
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Annekathrin Widmann
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - André Fiala
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany.
| |
Collapse
|
13
|
Sakimoto Y, Kida H, Mitsushima D. Temporal dynamics of learning-promoted synaptic diversity in CA1 pyramidal neurons. FASEB J 2019; 33:14382-14393. [PMID: 31689120 PMCID: PMC6894079 DOI: 10.1096/fj.201801893rrr] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although contextual learning requires plasticity at both excitatory and inhibitory (E/I) synapses in cornu ammonis 1 (CA1) neurons, the temporal dynamics across the neuronal population are poorly understood. Using an inhibitory avoidance task, we analyzed the dynamic changes in learning-induced E/I synaptic plasticity. The training strengthened GABAA receptor–mediated synapses within 1 min, peaked at 10 min, and lasted for over 60 min. The intracellular loop (Ser408−409) of GABAA receptor β3 subunit was also phosphorylated within 1 min of training. As the results of strengthening of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor–mediated synapses, CA1 pyramidal neurons exhibited broad diversity of E/I synaptic currents within 5 min. Moreover, presynaptic glutamate release probability at basal dendrites also increased within 5 min. To further quantify the diversified E/I synaptic currents, we calculated self-entropy (bit) for individual neurons. The neurons showed individual levels of the parameter, which rapidly increased within 1 min of training and maintained for over 60 min. These results suggest that learning-induced synaptic plasticity is critical immediately following encoding rather than during the retrieval phase of the learning. Understanding the temporal dynamics along with the quantification of synaptic diversity would be necessary to identify a failure point for learning-promoted plasticity in cognitive disorders.—Sakimoto, Y., Kida, H., Mitsushima, D. Temporal dynamics of learning-promoted synaptic diversity in CA1 pyramidal neurons.
Collapse
Affiliation(s)
- Yuya Sakimoto
- Department of Physiology, Graduate School of Medicine, Yamaguchi University, Ube, Japan
| | - Hiroyuki Kida
- Department of Physiology, Graduate School of Medicine, Yamaguchi University, Ube, Japan
| | - Dai Mitsushima
- Department of Physiology, Graduate School of Medicine, Yamaguchi University, Ube, Japan.,The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, Japan
| |
Collapse
|