Depolarization-induced synaptic plasticity at cholinergic synapses in tissue culture

Area of Science:

• Neuroscience
• Developmental Biology
• Cellular Neuroscience

Background:

• Synaptic connections undergo elimination and stabilization during neural development.
• The role of neuronal activity in synaptic remodeling is not fully understood.
• Cholinergic synapses form between NG108-15 neuroblastoma X glioma cells and skeletal myotubes in vitro.

Purpose of the Study:

• To investigate the impact of chronic neuronal depolarization on cholinergic synapse formation and stability.
• To determine if neuronal activity regulates synaptic elimination and innervation patterns in a tissue culture model.

Main Methods:

• Cultured NG108-15 cells and skeletal myotubes were used to form cholinergic synapses.
• Chronic depolarization was induced using veratridine.
• Synaptic activity was measured by stimulating hybrid cells and recording from myotubes.
• The effects of tetrodotoxin were assessed.

Main Results:

• Chronic depolarization significantly reduced the probability of synaptic connections and multiple innervation.
• The efficacy of remaining synapses was comparable to control conditions.
• Synapse numbers recovered to control levels after veratridine removal.
• Tetrodotoxin blocked the activity-dependent reduction in synaptic connections.

Conclusions:

• Neuronal activity plays a crucial role in regulating synaptic elimination and innervation patterns.
• The observed activity-dependent synapse remodeling suggests a mechanism for polyneuronal to mononeuronal innervation changes.
• This tissue culture system provides a model for studying activity-dependent synaptic plasticity and development.