Acute high glucose exposure impairs synaptosomal vesicle release activity

Area of Science:

• Neuroscience
• Biochemistry
• Metabolic disorders

Background:

• Alzheimer's disease (AD) and diabetes share a hyperglycemic phenotype.
• Vacuolar-type ATPase (V-ATPase) is crucial for neurotransmitter release, but its role in AD is unknown.

Purpose of the Study:

• To investigate how acute hyperglycemia affects synaptic vesicular exocytosis and V-ATPase function.
• To explore the link between hyperglycemia, V-ATPase, and synaptic transmission.

Main Methods:

• Synaptosomes from wildtype mouse brains were used.
• Synaptic exocytosis was measured via acridine orange (AO) and glutamate release.
• V-ATPase assembly and activity were assessed using co-immunoprecipitation and phosphate release assays.

Main Results:

• Acute hyperglycemia reduced synaptic vesicular exocytosis, indicated by lower AO and glutamate release.
• Hyperglycemia decreased synaptic V-ATPase assembly but did not affect V-ATPase-released phosphates.

Conclusions:

• Hyperglycemia impairs synaptic vesicular exocytosis, partly by reducing V-ATPase assembly.
• These findings suggest a shared molecular mechanism contributing to synaptic dysfunction in AD and diabetes.
• Further research is needed on chronic hyperglycemia and V-ATPase function in AD and diabetes models.