PreprintArticleVersion 2Preserved in Portico This version is not peer-reviewed
M1/M3 Muscarinic Acetylcholine Receptors Control Long-Term, but Not Short-Term Plasticity at the Mossy Fiber – CA3 Pyramidal Cell Synapse in Mouse Hippocampus
Version 1
: Received: 14 June 2023 / Approved: 15 June 2023 / Online: 15 June 2023 (12:39:05 CEST)
Version 2
: Received: 13 July 2023 / Approved: 13 July 2023 / Online: 14 July 2023 (09:24:01 CEST)
Zheng, F.; Wess, J.; Alzheimer, C. Long-Term—But Not Short-Term—Plasticity at the Mossy Fiber–CA3 Pyramidal Cell Synapse in Hippocampus Is Altered in M1/M3 Muscarinic Acetylcholine Receptor Double Knockout Mice. Cells2023, 12, 1890.
Zheng, F.; Wess, J.; Alzheimer, C. Long-Term—But Not Short-Term—Plasticity at the Mossy Fiber–CA3 Pyramidal Cell Synapse in Hippocampus Is Altered in M1/M3 Muscarinic Acetylcholine Receptor Double Knockout Mice. Cells 2023, 12, 1890.
Zheng, F.; Wess, J.; Alzheimer, C. Long-Term—But Not Short-Term—Plasticity at the Mossy Fiber–CA3 Pyramidal Cell Synapse in Hippocampus Is Altered in M1/M3 Muscarinic Acetylcholine Receptor Double Knockout Mice. Cells2023, 12, 1890.
Zheng, F.; Wess, J.; Alzheimer, C. Long-Term—But Not Short-Term—Plasticity at the Mossy Fiber–CA3 Pyramidal Cell Synapse in Hippocampus Is Altered in M1/M3 Muscarinic Acetylcholine Receptor Double Knockout Mice. Cells 2023, 12, 1890.
Abstract
Muscarinic acetylcholine receptors are well-known for their crucial involvement in hippocampus-dependent learning and memory, but the exact roles of the various receptor subtypes (M1-M5) are still not fully understood. Here, we studied how M1 and M3 receptors affect plasticity at the mossy fiber (MF)-CA3 pyramidal cell synapse. In hippocampal slices from M1/M3 receptor double knockout (M1/M3-dKO) mice, the signature short-term plasticity of the MF-CA3 synapse was not significantly affected. However, the rather unique, NMDA receptor-independent and presynaptic form of long-term potentiation (LTP) of this synapse was much larger in M1/M3-deficient slices compared to wild type slices, in both field potential and whole-cell recordings. Consistent with its presynaptic origin, induction of MF-LTP strongly enhanced the excitatory drive onto single CA3 pyramidal cells, with the effect being more pronounced in M1/M3-dKO cells. In an earlier study [1], we found that deletion of M2 receptors in mice disinhibits MF-LTP in a similar fashion, suggesting that endogenous acetylcholine employs both M1/M3 and M2 receptors to constrain MF-LTP. Importantly, such synergism was not observed for MF long-term depression (LTD). Low-frequency stimulation, which reliably induced LTD of MF synapses in control slices, failed to do so in M1/M3-dKO slices and gave rise to LTP instead. In striking contrast, loss of M2 augmented LTD when compared to control slices. Taken together, our data demonstrate convergence of M1/M3 and M2 receptors on MF-LTP, but functional divergence on MF-LTD, the net effect being well-balanced bidirectional plasticity of the MF-CA3 pyramidal cell synapse.
Biology and Life Sciences, Neuroscience and Neurology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Commenter: Christian Alzheimer
Commenter's Conflict of Interests: Author