Ultrafast endocytosis in mouse cortical inhibitory synapses

Area of Science:

• Neuroscience
• Cell Biology
• Synaptic Plasticity

Background:

• Neural circuit function relies on balanced excitatory and inhibitory activity.
• Synaptic vesicle recycling mechanisms are well-studied in excitatory synapses but less understood in inhibitory ones.

Purpose of the Study:

• To investigate the dynamics of synaptic vesicle recycling at inhibitory synapses.
• To determine if ultrafast endocytosis occurs at inhibitory synapses and identify involved proteins.

Main Methods:

• Utilized zap-and-freeze time-resolved electron microscopy on mouse acute cortical slices.
• Examined protein localization and vesicle dynamics at excitatory and inhibitory synapses post-stimulation.

Main Results:

• Identified depots of Dynamin 1xA, crucial for ultrafast endocytosis, near the active zone in both excitatory and inhibitory cortical synapses.
• Observed uncoated pits, indicative of ultrafast endocytic intermediates, at inhibitory synapses after stimulation.

Conclusions:

• Suggests that inhibitory synapses employ ultrafast endocytosis, similar to excitatory synapses.
• Highlights conserved mechanisms for synaptic vesicle recycling in the mammalian brain.