Electrochemistry at the Synapse

Abstract

Electrochemical measurements of neurotransmitters provide insight into the dynamics of neurotransmission. In this review, we describe the development of electrochemical measurements of neurotransmitters and how they started with extrasynaptic measurements but now are pushing toward synaptic measurements. Traditionally, biosensors or fast-scan cyclic voltammetry have monitored extrasynaptic levels of neurotransmitters, such as dopamine, serotonin, adenosine, glutamate, and acetylcholine. Amperometry and electrochemical cytometry techniques have revealed mechanisms of exocytosis, suggesting partial release. Advances in nanoelectrodes now allow spatially resolved, electrochemical measurements in a synapse, which is only 20–100 nm wide. Synaptic measurements of dopamine and acetylcholine have been made. In this article, electrochemical measurements are also compared to optical imaging and mass spectrometry measurements, and while these other techniques provide enhanced spatial or chemical information, electrochemistry is best at monitoring real-time neurotransmission. Future challenges include combining electrochemistry with these other techniques in order to facilitate multisite and multianalyte monitoring.

Subsecond spontaneous catecholamine release in mesenteric lymph node ex vivo

“…Transient CA release is rapid and frequent, lasting on average only 2 s and occurring only 10‐s apart. The sympathetic neural‐immune synapse is significantly shorter (Felten et al., 2018) than the neuron‐neuron synapse (6 nm compared to 20 nm) (Shin, Wang, Borgus, & Venton, 2019) which could facilitate a decrease in length of time CA spends in the extracellular space. Rapid fluctuations in CA also inform the time frame of neural‐immune crosstalk in the MLN.…”

Complex sex and estrous cycle differences in spontaneous transient adenosine

“…Adenosine was detected using fast‐scan cyclic voltammetry at a carbon‐fiber microelectrode, which allows real‐time measurement of adenosine changes with subsecond temporal resolution (Ganesana, Lee, Wang, & Venton, ; Nguyen & Venton, ; Shin, Wang, Borgus, & Venton, ; Swamy & Venton, ). This technique is best at identifying fast changes, due to background subtraction of data, and basal levels are not determined.…”

Organic Bioelectronics for Neurotransmitter Release at the Speed of Life

“…[13,28] On the millisecond scale, these vesicles are docked, activated, and fused with the cell membrane at the pre-synaptic cell. [21,29] The chemical synapse is separated by the synaptic cleft. Signaling occurs via vesicle release from the pre-synaptic neuron that di uses to the post-synaptic neuron where a reaction in triggered.…”

“…[126] The state-of-the-art microelectrodes provide impressively low detection limits as they are able to detect neurotransmitter content in single vesicles. [29]…”