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Seiler JL, Zhuang X, Nelson AB, Lerner TN. Dopamine across timescales and cell types: Relevance for phenotypes in Parkinson's disease progression. Exp Neurol 2024; 374:114693. [PMID: 38242300 DOI: 10.1016/j.expneurol.2024.114693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/09/2024] [Accepted: 01/15/2024] [Indexed: 01/21/2024]
Abstract
Dopamine neurons in the substantia nigra pars compacta (SNc) synthesize and release dopamine, a critical neurotransmitter for movement and learning. SNc dopamine neurons degenerate in Parkinson's Disease (PD), causing a host of motor and non-motor symptoms. Here, we review recent conceptual advances in our basic understanding of the dopamine system - including our rapidly advancing knowledge of dopamine neuron heterogeneity - with special attention to their importance for understanding PD. In PD patients, dopamine neuron degeneration progresses from lateral SNc to medial SNc, suggesting clinically relevant heterogeneity in dopamine neurons. With technical advances in dopamine system interrogation, we can understand the relevance of this heterogeneity for PD progression and harness it to develop new treatments.
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Affiliation(s)
- Jillian L Seiler
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Xiaowen Zhuang
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA; Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Alexandra B Nelson
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA; Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA, USA; Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Talia N Lerner
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Northwestern University Interdepartmental Neuroscience Program (NUIN), Evanston, IL, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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Hammer N, Vogel P, Lee S, Roeper J. Optogenetic action potentials and intrinsic pacemaker interplay in retrogradely identified midbrain dopamine neurons. Eur J Neurosci 2024; 59:1311-1331. [PMID: 38056070 DOI: 10.1111/ejn.16208] [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: 07/29/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 12/08/2023]
Abstract
Dissecting the diversity of midbrain dopamine (DA) neurons by optotagging is a promising addition to better identify their functional properties and contribution to motivated behavior. Retrograde molecular targeting of DA neurons with specific axonal projection allows further refinement of this approach. Here, we focus on adult mouse DA neurons in the substantia nigra pars compacta (SNc) projecting to dorsal striatum (DS) by demonstrating the selectivity of a floxed AAV9-based retrograde channelrhodopsin-eYFP (ChR-eYFP) labeling approach in DAT-cre mice. Furthermore, we show the utility of a sparse labeling version for anatomical single-cell reconstruction and demonstrate that ChR-eYFR expressing DA neurons retain intrinsic functional properties indistinguishable from conventionally retrogradely red-beads-labeled neurons. We systematically explore the properties of optogenetically evoked action potentials (oAPs) and their interaction with intrinsic pacemaking in this defined subpopulation of DA neurons. We found that the shape of the oAP and its first derivative, as a proxy for extracellularly recorded APs, is highly distinct from spontaneous APs (sAPs) of the same neurons and systematically varies across the pacemaker duty cycle. The timing of the oAP also affects the backbone oscillator of the intrinsic pacemaker by introducing transient "compensatory pauses". Characterizing this systematic interplay between oAPs and sAPs in defined DA neurons will also facilitate a refinement of DA neuron optotagging in vivo.
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Affiliation(s)
- Niklas Hammer
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, Germany
| | - Pascal Vogel
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, Germany
| | - Sanghun Lee
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, Germany
| | - Jochen Roeper
- Institute of Neurophysiology, Neuroscience Center, Goethe University Frankfurt, Germany
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