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Miranda-Barrientos J, Chambers I, Mongia S, Liu B, Wang HL, Mateo-Semidey GE, Margolis EB, Zhang S, Morales M. Ventral tegmental area GABA, glutamate, and glutamate-GABA neurons are heterogeneous in their electrophysiological and pharmacological properties. Eur J Neurosci 2021; 54:10.1111/ejn.15156. [PMID: 33619763 PMCID: PMC8380271 DOI: 10.1111/ejn.15156] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 01/05/2023]
Abstract
The ventral tegmental area (VTA) contains dopamine neurons intermixed with GABA-releasing (expressing vesicular GABA transporter, VGaT), glutamate-releasing (expressing vesicular glutamate transporter 2, VGluT2), and glutamate-GABA co-releasing (co-expressing VGluT2 and VGaT) neurons. By delivering INTRSECT viral vectors into the VTA of double vglut2-Cre/vgat-Flp transgenic mice, we targeted specific VTA cell populations for ex vivo recordings. We found that VGluT2+ VGaT- and VGluT2+ VGaT+ neurons on average had relatively hyperpolarized resting membrane potential, greater rheobase, and lower spontaneous firing frequency compared to VGluT2- VGaT+ neurons, suggesting that VTA glutamate-releasing and glutamate-GABA co-releasing neurons require stronger excitatory drive to fire than GABA-releasing neurons. In addition, we detected expression of Oprm1mRNA (encoding µ opioid receptors, MOR) in VGluT2+ VGaT- and VGluT2- VGaT+ neurons, and that the MOR agonist DAMGO hyperpolarized neurons with these phenotypes. Collectively, we demonstrate the utility of the double transgenic mouse to access VTA glutamate, glutamate-GABA, and GABA neurons to determine their electrophysiological properties. SIGNIFICANT STATEMENT: Some physiological properties of VTA glutamate-releasing and glutamate-GABA co-releasing neurons are distinct from those of VTA GABA-releasing neurons. µ-opioid receptor activation hyperpolarizes some VTA glutamate-releasing and some GABA-releasing neurons.
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Affiliation(s)
| | - Ian Chambers
- Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA
| | - Smriti Mongia
- Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA
| | - Bing Liu
- Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA
| | - Hui-Ling Wang
- Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA
| | | | - Elyssa B. Margolis
- UCSF Weill Institute of Neurosciences|Department of Neurology, University of California, San Francisco, CA, USA
| | - Shiliang Zhang
- Confocal and Electron Microscopy Core, National Institute on Drug Abuse, Baltimore, MD, USA
| | - Marisela Morales
- Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA
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