Molecular Neuroscience: Synapses and Neurotransmitters (Flashcards)

A comprehensive set of Q&A flashcards covering neurotransmitters, synapse types, receptor biology, synaptic machinery, and disease-linked molecular targets based on the lecture notes.

What enzyme converts glutamate to GABA?

Glutamate decarboxylase (GAD).

Which neurotransmitter is the major excitatory transmitter by abundance?

Glutamate.

Which neurotransmitter is synthesized from glutamate by GAD and acts as an inhibitory transmitter?

GABA.

In neurons, which part is the presynaptic nerve terminal?

Axon.

In neurons, which part is the postsynaptic nerve terminal?

Dendrite.

What motor protein moves along microtubules toward the plus end to transport macromolecules to distal parts of the neuron?

Kinesin (ATP-dependent motor protein).

In which direction do kinesins move along microtubules?

Toward the plus end (anterograde transport).

What type of synapse allows direct electrical signaling between two neurons?

Electrical synapse.

What structure forms electrical synapses by connecting cells?

Gap junctions (hexameric channels with six subunits).

What triggers vesicle fusion in chemical synapses?

Calcium influx into the nerve terminal.

Which protein senses Ca2+ and triggers vesicle fusion in chemical synapses?

Synaptotagmin.

What mediates vesicle fusion with the plasma membrane in chemical synapses?

SNARE proteins.

What happens after neurotransmitter is released into the synaptic cleft?

It diffuses across the cleft and binds to postsynaptic receptors.

What ion influx initiates neurotransmitter release at chemical synapses?

Ca2+ influx into the nerve terminal.

When receptors bind neurotransmitter, what is their general function?

They act as ion channels or gates to allow ion flow.

How can neurotransmitter binding affect the postsynaptic membrane potential?

Excitatory (depolarizing) via Na+ influx or inhibitory (hyperpolarizing) via Cl- influx.ить

How is the chemical signal terminated at the synapse?

Diffusion away from the cleft or reuptake by membrane transporters.

Where are major excitatory synapses typically located and which transmitter do they use?

On dendrites; glutamate.

Name two common synapse types based on pre- and postsynaptic locations.

Axo-dendritic and axo-somatic synapses.

Where are major inhibitory synapses typically located and which transmitters do they use?

On the cell body (soma); GABA or glycine.

How many subunits do glutamate receptors have and where does glutamate bind?

Four subunits; glutamate binds on the outside at the cation channel.

Which intracellular scaffold protein binds glutamate receptors at excitatory synapses?

PSD-95.

How many subunits do GABA receptors have and where does glycine bind?

Five subunits; glycine binds on the outside at the anion channel.

Which intracellular protein binds inhibitory receptors such as GABA and glycine receptors?

Gephyrin.

Which neuroligin subtypes are associated with excitatory synapses?

Neuroligin 1, 3, and 4.

Which neuroligin subtype is associated with inhibitory synapses?

Neuroligin 2.

Which receptor type is implicated in cognitive decline and major brain communication as excitatory signaling?

Glutamate receptors.

Which scaffolding protein organizes excitation and is a therapeutic target for stroke?

PSD-95.

Which receptors mediate inhibition and are linked to hyperekplexia?

Glycine receptors.

Which scaffolding protein organizes inhibitory synapses?

Gephyrin.

Which synaptic adhesion molecules are linked to autism and schizophrenia through mutation effects on synapses?

Neurexin and Neuroligin.

What is a pharmacological strategy to reduce over-excitation by targeting the PSD-95–receptor interaction?

Inhibitors that prevent PSD-95 from binding to the receptor.

What therapy is mentioned as a way to modulate inhibition via immunoglobulins?

Intravenous IgG (IVIG) therapy.

What broader approach is suggested for modulating neural activity at the gene level?

Gene therapy.

What is one example of a drug-target strategy related to synaptic regulation mentioned in the notes?

Receptor regulators used in pain and muscle relaxants.