Counting the Number of Glutamate Molecules in Single Synaptic Vesicles
Artikel i vetenskaplig tidskrift, 2019

Analytical tools for quantitative measurements of glutamate, the principal excitatory neurotransmitter in the brain, are lacking. Here, we introduce a new enzyme-based amperometric sensor technique for the counting of glutamate molecules stored inside single synaptic vesicles. In this method, an ultra-fast enzyme-based glutamate sensor is placed into a solution of isolated synaptic vesicles, which stochastically rupture at the sensor surface in a potential-dependent manner at a constant negative potential. The continuous amperometric signals are sampled at high speed (10 kHz) to record sub-millisecond spikes, which represent glutamate release from single vesicles that burst open. Glutamate quantification is achieved by a calibration curve that is based on measurements of glutamate release from vesicles pre-filled with various glutamate concentrations. Our measurements show that an isolated single synaptic vesicle encapsulates about 8000 glutamate molecules and is comparable to the measured exocytotic quantal glutamate release in amperometric glutamate sensing in the nucleus accumbens of mouse brain tissue. Hence, this new methodology introduces the means to quantify ultra-small amounts of glutamate and to study synaptic vesicle physiology, pathogenesis, and drug treatments for neuronal disorders where glutamate is involved. ©

Författare

Yuanmo Wang

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

Hoda Mashadi Fathali

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Devesh Mishra

Wallenberg Lab.

Göteborgs universitet

Thomas Olsson

Chalmers, Fysik, Biologisk fysik

Jacqueline Keighron

New York Institute of Technology

Karolina P. Skibicka

Wallenberg Lab.

Göteborgs universitet

Ann-Sofie Cans

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 141 44 17507-17511

Ämneskategorier

Medicinsk laboratorie- och mätteknik

Analytisk kemi

Medicinsk apparatteknik

DOI

10.1021/jacs.9b09414

PubMed

31644274

Mer information

Senast uppdaterat

2019-11-22