Stress enhances electrical synapse formation between regenerating neurons

Area of Science:

• Neuroscience
• Cellular Biology
• Synaptic Plasticity

Background:

• Adult molluscan neurons L5 and R5 exhibit sprouting and form new electrical synapses after axotomy.
• Stress can induce sprouting in these neurons within an intact nervous system.

Purpose of the Study:

• To investigate the effect of prior stress on the strength of electrical coupling between sprouting neurons L5 and R5.
• To determine the underlying mechanisms of stress-induced changes in synaptic strength.

Main Methods:

• Electrophysiological recordings were used to measure electrical coupling between neurons L5 and R5.
• Animals were subjected to prior stress conditions before axotomy or stress induction.
• Coupling resistance and the degree of neuronal sprouting were quantified.

Main Results:

• Electrical coupling strength between neurons L5 and R5 increased during sprouting in ganglia from previously stressed animals.
• This increase in coupling strength was attributed to a decrease in coupling resistance.
• No significant change in the degree of sprouting was observed between stressed and non-stressed groups.

Conclusions:

• Prior stress can potentiate the formation and strength of new electrical synapses between sprouting neurons.
• Reduced coupling resistance is a key factor in stress-induced enhancement of electrical synapse strength.
• These findings highlight the role of prior experience in modulating neuronal repair and synaptic function.