Dopaminergic neurons establish a distinctive axonal arbor with a majority of non-synaptic terminals.

TitleDopaminergic neurons establish a distinctive axonal arbor with a majority of non-synaptic terminals.
Publication TypeJournal Article
Year of Publication2021
AuthorsDucrot, C, Bourque, M-J, Delmas, CVL, Racine, A-S, Bello, DGuadarrama, Delignat-Lavaud, B, Lycas, MDomenic, Fallon, A, Michaud-Tardif, C, Nanni, SBurke, Herborg, F, Gether, U, Nanci, A, Takahashi, H, Parent, M, Trudeau, L-E
JournalFASEB J
Volume35
Issue8
Paginatione21791
Date Published2021 08
ISSN1530-6860
KeywordsAnimals, Axons, Calcium-Binding Proteins, Cell Adhesion Molecules, Neuronal, Cell Differentiation, Coculture Techniques, Corpus Striatum, Dopamine, Dopaminergic Neurons, Gene Expression Regulation, Green Fluorescent Proteins, Immunohistochemistry, Mice, Transgenic, Nerve Tissue Proteins, Neural Cell Adhesion Molecules, Tyrosine 3-Monooxygenase
Abstract

Chemical neurotransmission typically occurs through synapses. Previous ultrastructural examinations of monoamine neuron axon terminals often failed to identify a pre- and postsynaptic coupling, leading to the concept of "volume" transmission. Whether this results from intrinsic properties of these neurons remains undefined. We find that dopaminergic neurons in vitro establish a distinctive axonal arbor compared to glutamatergic or GABAergic neurons in both size and propensity of terminals to avoid direct contact with target neurons. While most dopaminergic varicosities are active and contain exocytosis proteins like synaptotagmin 1, only ~20% of these are synaptic. The active zone protein bassoon was found to be enriched in dopaminergic terminals that are in proximity to a target cell. Finally, we found that the proteins neurexin-1α and neuroligin-1 play a critical role in the formation of synapses by dopamine (DA) neurons. Our findings suggest that DA neurons are endowed with a distinctive developmental connectivity program.

DOI10.1096/fj.202100201RR
Alternate JournalFASEB J
PubMed ID34320240
Grant ListMOP106556 / / CIHR / Canada