Evidence for ectopic neurotransmission at a neuronal synapse.
Neurotransmitter release is well known to occur at specialized synaptic regions that include presynaptic active zones and postsynaptic densities. At cholinergic synapses in the chick ciliary ganglion, however, membrane formations and physiological measurements suggest that release distant from postsynaptic densities can activate the predominantly extrasynaptic alpha7 nicotinic receptor subtype. We explored such ectopic neurotransmission with a novel model synapse that combines Monte Carlo simulations with high-resolution serial electron microscopic tomography. Simulated synaptic activity is consistent with experimental recordings of miniature excitatory postsynaptic currents only when ectopic transmission is included in the model, broadening the possibilities for mechanisms of neuronal communication.
Coggan
Jay S
JS
Computational Neurobiology Laboratory, The Salk Institute, La Jolla, CA 92037, USA.
Bartol
Thomas M
TM
Esquenazi
Eduardo
E
Stiles
Joel R
JR
Lamont
Stephan
S
Martone
Maryann E
ME
Berg
Darwin K
DK
Ellisman
Mark H
MH
Sejnowski
Terrence J
TJ
D000109:Acetylcholine / Q000378:metabolism; D000110:Acetylcholinesterase / Q000378:metabolism; D000465:Algorithms; D000818:Animals; D002642:Chick Embryo; D003198:Computer Simulation; D004058:Diffusion; D019706:Excitatory Postsynaptic Potentials; D005726:Ganglia, Parasympathetic / Q000502:physiology* / Q000648:ultrastructure; D007091:Image Processing, Computer-Assisted; D008433:Mathematics; D008854:Microscopy, Electron; D008959:Models, Neurological; D009010:Monte Carlo Method; D018408:Patch-Clamp Techniques; D011336:Probability; D011978:Receptors, Nicotinic / Q000378:metabolism; D012680:Sensitivity and Specificity; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D013570:Synaptic Membranes / Q000378:metabolism; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism
D000109:Acetylcholine; D000110:Acetylcholinesterase; D011978:Receptors, Nicotinic