Journal Article

Rapid and modifiable neurotransmitter receptor dynamics at a neuronal synapse in vivo

Kim, Han, Lichtman, Jeff W, McCann, Corey M, Tapia, Juan Carlos, Coggan, Jay S

2008

Overview

In vivo , synaptic receptor densities were maintained over minutes by a rapid exchange with nonsynaptic receptor pools and over hours through turnover. These changes and receptor dynamics may represent the initial phases of synaptic efficacy modulation before eventual structural modification involving spine growth or retraction. 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.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: Analysis of Variance / Animal Genetics and Genomics / Animals / Axotomy - methods / Behavioral Sciences / Biological Techniques / Biomedical and Life Sciences / Biomedicine / Bungarotoxins - metabolism / Excitatory Postsynaptic Potentials - physiology / Excitatory Postsynaptic Potentials - radiation effects / Gene Expression Regulation - physiology / In Vitro Techniques / Intracellular Signaling Peptides and Proteins - metabolism / Luminescent Proteins - metabolism / Mice / Mice, Transgenic / Neurobiology / Neurons - cytology / Neurons - metabolism / Neuroplasticity / Neurosciences / Neurotransmitter receptors / Nonlinear Dynamics / Physiological aspects / Presynaptic Terminals - physiology / Presynaptic Terminals - radiation effects / Receptors, Cholinergic - classification / Receptors, Cholinergic - metabolism / Receptors, Cholinergic - ultrastructure / Submandibular Gland - cytology / Synapses / Synapses - metabolism / Time Factors