title: Chemical transmission between dopaminergic neuron pairs.
abstract: Midbrain dopaminergic (DAergic) neurons play a major regulatory role in in goal-directed behavior and reinforcement learning. DAergic neuron activity, and therefore spatiotemporal properties of dopamine release, precisely encodes reward signals. Neuronal activity is shaped both by external afferences and local interactions (chemical and electrical transmissions). Numerous hints suggest the existence of chemical interactions between DAergic neurons, but direct evidence and characterization are still lacking. Here, we show, using dual patch-clamp recordings in rat brain slices, a widespread bidirectional chemical transmission between DAergic neuron pairs. Hyperpolarizing postsynaptic potentials were partially mediated by D2-like receptors, and entirely resulted from the inhibition of the hyperpolarization-activated depolarizing current (Ih). These results constitute the first evidence in paired recordings of a chemical transmission relying on conductance decrease in mammals. In addition, we show that chemical transmission and electrical synapses frequently coexist within the same neuron pair and dynamically interact to shape DAergic neuron activity.
authors.affiliation: Université Pierre et Marie Curie, Paris 75005, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Vandecasteele
authors.forename: Jacques
authors.initials: J
authors.lastname: Glowinski
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Deniau
authors.forename: Laurent
authors.initials: L
authors.lastname: Venance
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004553:Electric Conductivity; D018698:Glutamic Acid / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D018698:Glutamic Acid; D004298:Dopamine