title: Acetylcholine α7 nicotinic and dopamine D2 receptors are targeted to many of the same postsynaptic dendrites and astrocytes in the rodent prefrontal cortex.
abstract: The alpha-7 nicotinic acetylcholine receptor (α7nAChR) and the dopamine D(2) receptor (D(2) R) are both implicated in attentional processes and cognition, mediated in part through the prefrontal cortex (PFC). We examined the dual electron microscopic immunolabeling of α7nAChR and either D(2) R or the vesicular acetylcholine transporter (VAChT) in rodent PFC to assess convergent functional activation sites. Immunoreactivity (ir) for α7nAChR and/or D(2) R was seen in the same as well as separate neuronal and glial profiles. At least half of the dually labeled profiles were somata and dendrites, while most labeled axon terminals expressed only D(2) R-ir. The D(2) R-labeled terminals were without synaptic specializations or formed inhibitory or excitatory-type synapses with somatodendritic profiles, some of which expressed the α7nAChR and/or D(2) R. Astrocytic glial processes comprised the majority of nonsomatodendritic α7nAChR or α7nAChR and D(2) R-labeled profiles. Glial processes containing α7nAChR-ir were frequently located near VAChT-labeled terminals and also showed perisynaptic and perivascular associations. We conclude that in rodent PFC α7nACh and D(2) R activation can dually modulate (1) postsynaptic dendritic responses within the same or separate but synaptically linked neurons in which the D(2) R has the predominately presynaptic distribution, and (2) astrocytic signaling that may be crucial for synaptic transmission and functional hyperemia.
authors.affiliation: Department of Neurology and Neuroscience, Division of Neurobiology, Weill Cornell Medical College, New York, New York 10065, USA.
authors.forename: Aine M
authors.initials: AM
authors.lastname: Duffy
authors.forename: Megan L
authors.initials: ML
authors.lastname: Fitzgerald
authors.forename: June
authors.initials: J
authors.lastname: Chan
authors.forename: Danielle C
authors.initials: DC
authors.lastname: Robinson
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Milner
authors.forename: Kenneth
authors.initials: K
authors.lastname: Mackie
authors.forename: Virginia M
authors.initials: VM
authors.lastname: Pickel
mesh_terms: D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000648:ultrastructure; D002450:Cell Communication / Q000502:physiology; D003712:Dendrites / Q000378:metabolism* / Q000648:ultrastructure; D004298:Dopamine / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016253:Microscopy, Immunoelectron / Q000379:methods; D017397:Prefrontal Cortex / Q000166:cytology / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D050494:Vesicular Acetylcholine Transport Proteins / Q000378:metabolism; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: C579166:Chrna7 protein, mouse; C579165:Chrna7 protein, rat; D017448:Receptors, Dopamine D2; D011978:Receptors, Nicotinic; D050494:Vesicular Acetylcholine Transport Proteins; D064569:alpha7 Nicotinic Acetylcholine Receptor; D000109:Acetylcholine; D004298:Dopamine