Excitatory Neurotransmitter Release

Source: Soukupová, M., et al. Microdialysis of Excitatory Amino Acids During EEG Recordings in Freely Moving Rats. J. Vis. Exp. (2018)This video demonstrates the assessment of extracellular excitatory neurotransmitter levels in rats with chronic epilepsy induction. After implanting a microdialysis probe into the brain and confirming the absence of seizures using electroencephalography (EEG), extracellular fluid is collected to evaluate elevated neurotransmitter levels in epileptic rats. A...

When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of specific...

Source: Lacin, E., et al. Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters (CNiFERs) for Optical Detection of Neurotransmitters In Vivo. J. Vis. Exp. (2016)This video demonstrates a technique for imaging neurotransmitter release in vivo using cell-based neurotransmitter fluorescent engineered reporters (CNiFERs), specialized reporter cells pre-injected into the mouse cortex. Positioned under a two-photon microscope, the mouse allows visualization of...

Certain drugs can affect how neurotransmitters called catecholamines, are released or taken back up in the adrenergic neuron. They can have different effects on the body's sympathetic transmission. Reserpine, a natural compound found in the Rauwolfia shrub, blocks a transporter called vesicular monoamine transporter (VMAT), which leads to a buildup of catecholamines in the cell and reduces sympathetic transmission. Another drug called guanethidine works in multiple ways, including blocking...

This video demonstrates microRNA-mediated inhibition of excitatory synaptic currents in mouse hippocampal brain slices. The CA3 neurons were infected with a recombinant viral vector harboring a construct for expressing a fluorescent reporter, a light-activated membrane channel, and a microRNA that downregulates the expression of voltage-gated calcium channels. Upon placing a slice in a recording chamber and patching a CA1 neuron with a recording pipette, light pulses were used to stimulate the...