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Oh MA, Shin CI, Kim M, Kim J, Kang CM, Han SH, Sun JY, Oh SS, Kim YR, Chung TD. Inverted Ion Current Rectification-Based Chemical Delivery Probes for Stimulation of Neurons. ACS APPLIED MATERIALS & INTERFACES 2021; 13:26748-26758. [PMID: 34078075 DOI: 10.1021/acsami.1c04949] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ion current rectification (ICR), diodelike behavior in surface-charged nanopores, shows promise in the design of delivery probes for manipulation of neural networks as it can solve diffusive leakages that might be critical in clinical and research applications. However, it has not been achieved because ICR has restrictions in nanosized dimension and low electrolyte concentration, and rectification direction is inappropriate for delivery. Herein, we present a polyelectrolyte gel-filled (PGF) micropipette harnessing inverted ICR as a delivery probe, which quantitatively transports glutamate to stimulate primary cultured neurons with high efficiency while minimizing leakages. Since the gel works as an ensemble of numerous surface-charged nanopores, the current is rectified in the micro-opening and physiological environment. By extending the charge-selective region using the gel, inverted ICR is generated, which drives outward deliveries of major charge carriers. This study will help in exploring new aspects of ICR and broaden its applications for advanced chemical delivery.
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Affiliation(s)
- Min-Ah Oh
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
| | - Chang Il Shin
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
| | - Moonjoo Kim
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
| | - Jayol Kim
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
| | - Chung Mu Kang
- Electrochemistry Laboratory, Advanced Institutes of Convergence Technology, 16229 Suwon-Si, Gyeonggi-do, Republic of Korea
| | - Seok Hee Han
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
| | - Jeong-Yun Sun
- Department of Materials Science & Engineering, Seoul National University, 08826 Seoul, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 08826 Seoul, Republic of Korea
| | - Seung Soo Oh
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 37673 Pohang, Gyeongbuk, South Korea
| | - Yang-Rae Kim
- Department of Chemistry, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Taek Dong Chung
- Department of Chemistry, Seoul National University, 08826 Seoul, Republic of Korea
- Electrochemistry Laboratory, Advanced Institutes of Convergence Technology, 16229 Suwon-Si, Gyeonggi-do, Republic of Korea
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Elgueta C, Bartos M. Dendritic inhibition differentially regulates excitability of dentate gyrus parvalbumin-expressing interneurons and granule cells. Nat Commun 2019; 10:5561. [PMID: 31804491 PMCID: PMC6895125 DOI: 10.1038/s41467-019-13533-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/11/2019] [Indexed: 11/25/2022] Open
Abstract
Fast-spiking parvalbumin-expressing interneurons (PVIs) and granule cells (GCs) of the dentate gyrus receive layer-specific dendritic inhibition. Its impact on PVI and GC excitability is, however, unknown. By applying whole-cell recordings, GABA uncaging and single-cell-modeling, we show that proximal dendritic inhibition in PVIs is less efficient in lowering perforant path-mediated subthreshold depolarization than distal inhibition but both are highly efficient in silencing PVIs. These inhibitory effects can be explained by proximal shunting and distal strong hyperpolarizing inhibition. In contrast, GC proximal but not distal inhibition is the primary regulator of their excitability and recruitment. In GCs inhibition is hyperpolarizing along the entire somato-dendritic axis with similar strength. Thus, dendritic inhibition differentially controls input-output transformations in PVIs and GCs. Dendritic inhibition in PVIs is suited to balance PVI discharges in dependence on global network activity thereby providing strong and tuned perisomatic inhibition that contributes to the sparse representation of information in GC assemblies. Fast-spiking parvalbumin-expressing interneurons (PVIs) and granule cells of the dentate gyrus receive layer-specific dendritic inhibition. The authors show that distal and proximal dendritic inhibition differentially control input-output transformations in PVIs and granule cells.
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Affiliation(s)
- Claudio Elgueta
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Medical Faculty of the University of Freiburg, 79104, Freiburg, Germany.
| | - Marlene Bartos
- Institute for Physiology I, Cellular and Systemic Neurophysiology, Medical Faculty of the University of Freiburg, 79104, Freiburg, Germany.
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Chemogenetic Isolation Reveals Synaptic Contribution of δ GABA A Receptors in Mouse Dentate Granule Neurons. J Neurosci 2018; 38:8128-8145. [PMID: 30076210 DOI: 10.1523/jneurosci.0799-18.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/18/2018] [Accepted: 07/24/2018] [Indexed: 11/21/2022] Open
Abstract
Two major GABAA receptor classes mediate ionotropic GABA signaling, those containing a δ subunit and those with a γ2 subunit. The classical viewpoint equates γ2-containing receptors with IPSCs and δ-containing receptors with tonic inhibition because of differences in receptor localization, but significant questions remain because the populations cannot be pharmacologically separated. We removed this barrier using gene editing to confer a point mutation on the δ subunit in mice, rendering receptors containing the subunit picrotoxin resistant. By pharmacologically isolating δ-containing receptors, our results demonstrate their contribution to IPSCs in dentate granule neurons and weaker contributions to thalamocortical IPSCs. Despite documented extrasynaptic localization, we found that receptor localization does not preclude participation in isolated IPSCs, including mIPSCs. Further, phasic inhibition from δ subunit-containing receptors strongly inhibited summation of EPSPs, whereas tonic activity had little impact. In addition to any role that δ-containing receptors may play in canonical tonic inhibition, our results highlight a previously underestimated contribution of δ-containing receptors to phasic inhibition.SIGNIFICANCE STATEMENT GABAA receptors play key roles in transient and tonic inhibition. The prevailing view suggests that synaptic γ2-containing GABAA receptors drive phasic inhibition, whereas extrasynaptic δ-containing receptors mediate tonic inhibition. To re-evaluate the impact of δ receptors, we took a chemogenetic approach that offers a sensitive method to probe the synaptic contribution of δ-containing receptors. Our results reveal that localization does not strongly limit the contribution of δ receptors to IPSCs and that δ receptors make an unanticipated robust contribution to phasic inhibition.
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