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Cholinergic afferent stimulation induces axonal function plasticity in adult hippocampal granule cells.

Martinello K, Huang Z, Lujan R, Tran B, Watanabe M, Cooper EC, Brown DA, Shah MM - Neuron (2015)

Bottom Line: The effects of acetylcholine on axonal information processing, though, remain unknown.In support, immunohistochemistry revealed muscarinic M1 receptor, CaV3.2, and KV7.2/7.3 subunit localization in granule cell axons.Since alterations in axonal signaling affect neuronal firing patterns and neurotransmitter release, this is an unreported cellular mechanism by which acetylcholine might, at least partly, enhance cognitive processing.

View Article: PubMed Central - PubMed

Affiliation: UCL School of Pharmacy, University College London, London, WC1N 1AX, UK.

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Muscarinic Receptor Activation Induces Sustained Ca2+ Entry via Axonal T-Type Ca2+ Channels(Ai) Electron micrographs showing immunogold particles (as indicated by arrows) for CaV3.2 subunits. Scale bar, 0.2 μm.(Aii) Immunogold particle quantification in dentate gyrus.(Bi) A two-photon image of a granule cell filled with Alexa Fluor 594 for 30 min. Cross-section line scans were obtained approximately 25 μm from the cell body as shown by the yellow bar.(Bii and Biii) Average line scan images obtained using Alexa Fluor 594 and Oregon green Bapta-1 (OGB-1) under control conditions, after 10 min Oxo-M (1 μM), and following 40 min washout of Oxo-M in the absence and presence of TTA-P2 (500 nM), respectively.(Biv and Bv) Individual (gray open squares) and average (black filled squares) ΔG/R measurements before, after Oxo-M treatment, and following Oxo-M washout in the absence and presence of TTA-P2.(Ci) Superimposed example single action potentials and associated axonal [Ca2+]i signals before, during, and after 25 min washout of Oxo-M.(Cii) Average ΔG/R measurements for action potential-associated [Ca2+]I signals under control conditions, after 10 min Oxo-M application, and following 25 min washout of Oxo-M.
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fig7: Muscarinic Receptor Activation Induces Sustained Ca2+ Entry via Axonal T-Type Ca2+ Channels(Ai) Electron micrographs showing immunogold particles (as indicated by arrows) for CaV3.2 subunits. Scale bar, 0.2 μm.(Aii) Immunogold particle quantification in dentate gyrus.(Bi) A two-photon image of a granule cell filled with Alexa Fluor 594 for 30 min. Cross-section line scans were obtained approximately 25 μm from the cell body as shown by the yellow bar.(Bii and Biii) Average line scan images obtained using Alexa Fluor 594 and Oregon green Bapta-1 (OGB-1) under control conditions, after 10 min Oxo-M (1 μM), and following 40 min washout of Oxo-M in the absence and presence of TTA-P2 (500 nM), respectively.(Biv and Bv) Individual (gray open squares) and average (black filled squares) ΔG/R measurements before, after Oxo-M treatment, and following Oxo-M washout in the absence and presence of TTA-P2.(Ci) Superimposed example single action potentials and associated axonal [Ca2+]i signals before, during, and after 25 min washout of Oxo-M.(Cii) Average ΔG/R measurements for action potential-associated [Ca2+]I signals under control conditions, after 10 min Oxo-M application, and following 25 min washout of Oxo-M.

Mentions: We next asked whether T-type Ca2+ channels are present in mossy fibers. Three subunits, CaV3.1–3.3, encode for T-type Ca2+ channels (Catterall, 2011). CaV3.2 antibody immunogold particles were detected on wild-type axons, dendrites, and somata spines (Figure 7A). The granule cell axon CaV3.2 labeling, although less than in dendrites and spines, was significantly greater than that in CaV3.2 granule cell axons (Figure 7A), indicating that CaV3.2 subunits are located in mossy fibers.


Cholinergic afferent stimulation induces axonal function plasticity in adult hippocampal granule cells.

Martinello K, Huang Z, Lujan R, Tran B, Watanabe M, Cooper EC, Brown DA, Shah MM - Neuron (2015)

Muscarinic Receptor Activation Induces Sustained Ca2+ Entry via Axonal T-Type Ca2+ Channels(Ai) Electron micrographs showing immunogold particles (as indicated by arrows) for CaV3.2 subunits. Scale bar, 0.2 μm.(Aii) Immunogold particle quantification in dentate gyrus.(Bi) A two-photon image of a granule cell filled with Alexa Fluor 594 for 30 min. Cross-section line scans were obtained approximately 25 μm from the cell body as shown by the yellow bar.(Bii and Biii) Average line scan images obtained using Alexa Fluor 594 and Oregon green Bapta-1 (OGB-1) under control conditions, after 10 min Oxo-M (1 μM), and following 40 min washout of Oxo-M in the absence and presence of TTA-P2 (500 nM), respectively.(Biv and Bv) Individual (gray open squares) and average (black filled squares) ΔG/R measurements before, after Oxo-M treatment, and following Oxo-M washout in the absence and presence of TTA-P2.(Ci) Superimposed example single action potentials and associated axonal [Ca2+]i signals before, during, and after 25 min washout of Oxo-M.(Cii) Average ΔG/R measurements for action potential-associated [Ca2+]I signals under control conditions, after 10 min Oxo-M application, and following 25 min washout of Oxo-M.
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fig7: Muscarinic Receptor Activation Induces Sustained Ca2+ Entry via Axonal T-Type Ca2+ Channels(Ai) Electron micrographs showing immunogold particles (as indicated by arrows) for CaV3.2 subunits. Scale bar, 0.2 μm.(Aii) Immunogold particle quantification in dentate gyrus.(Bi) A two-photon image of a granule cell filled with Alexa Fluor 594 for 30 min. Cross-section line scans were obtained approximately 25 μm from the cell body as shown by the yellow bar.(Bii and Biii) Average line scan images obtained using Alexa Fluor 594 and Oregon green Bapta-1 (OGB-1) under control conditions, after 10 min Oxo-M (1 μM), and following 40 min washout of Oxo-M in the absence and presence of TTA-P2 (500 nM), respectively.(Biv and Bv) Individual (gray open squares) and average (black filled squares) ΔG/R measurements before, after Oxo-M treatment, and following Oxo-M washout in the absence and presence of TTA-P2.(Ci) Superimposed example single action potentials and associated axonal [Ca2+]i signals before, during, and after 25 min washout of Oxo-M.(Cii) Average ΔG/R measurements for action potential-associated [Ca2+]I signals under control conditions, after 10 min Oxo-M application, and following 25 min washout of Oxo-M.
Mentions: We next asked whether T-type Ca2+ channels are present in mossy fibers. Three subunits, CaV3.1–3.3, encode for T-type Ca2+ channels (Catterall, 2011). CaV3.2 antibody immunogold particles were detected on wild-type axons, dendrites, and somata spines (Figure 7A). The granule cell axon CaV3.2 labeling, although less than in dendrites and spines, was significantly greater than that in CaV3.2 granule cell axons (Figure 7A), indicating that CaV3.2 subunits are located in mossy fibers.

Bottom Line: The effects of acetylcholine on axonal information processing, though, remain unknown.In support, immunohistochemistry revealed muscarinic M1 receptor, CaV3.2, and KV7.2/7.3 subunit localization in granule cell axons.Since alterations in axonal signaling affect neuronal firing patterns and neurotransmitter release, this is an unreported cellular mechanism by which acetylcholine might, at least partly, enhance cognitive processing.

View Article: PubMed Central - PubMed

Affiliation: UCL School of Pharmacy, University College London, London, WC1N 1AX, UK.

Show MeSH
Related in: MedlinePlus