Rapid and modifiable neurotransmitter receptor dynamics at a neuronal synapse in vivo.
Synaptic plasticity underlies the adaptability of the mammalian brain, but has been difficult to study in living animals. Here we imaged the synapses between pre- and postganglionic neurons in the mouse submandibular ganglion in vivo, focusing on the mechanisms that maintain and regulate neurotransmitter receptor density at postsynaptic sites. Normally, synaptic receptor densities were maintained by rapid exchange of receptors with nonsynaptic regions (over minutes) and by continual turnover of cell surface receptors (over hours). However, after ganglion cell axons were crushed, synaptic receptors showed greater lateral mobility and there was a precipitous decline in insertion. These changes led to near-complete loss of synaptic receptors and synaptic depression. Disappearance of postsynaptic spines and presynaptic terminals followed this acute synaptic depression. Therefore, neurotransmitter receptor dynamism associated with rapid changes in synaptic efficacy precedes long-lasting structural changes in synaptic connectivity.
Department of Molecular & Cellular Biology, Harvard University, 7 Divinity Ave., Cambridge, Massachusetts 02138, USA.
Corey M
CM
McCann
Juan Carlos
JC
Tapia
Han
H
Kim
Jay S
JS
Coggan
Jeff W
JW
Lichtman
D000704:Analysis of Variance; D000818:Animals; D019771:Axotomy / Q000379:methods; D002038:Bungarotoxins / Q000378:metabolism; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000502:physiology; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D017711:Nonlinear Dynamics; D017729:Presynaptic Terminals / Q000502:physiology / Q000528:radiation effects; D011950:Receptors, Cholinergic / Q000145:classification / Q000378:metabolism* / Q000648:ultrastructure; D013363:Submandibular Gland / Q000166:cytology; D013569:Synapses / Q000378:metabolism*; D013997:Time Factors
D002038:Bungarotoxins; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D011950:Receptors, Cholinergic