Molecular Neuroscience Flashcards
Most common neurotransmitters in the brain?
Glutamate and GABA
What is GABA?
Inhibitory neurotransmitter
What is glutamate?
Excitatory neurotransmitter
What enzyme produces GABA from glutamate?
Glutamate decarboxylase (GAD)
Post and presynaptic terminals have a cytoskeleton made of….
Actin
Microtubules are in dendrites and axons but what directions
Axons- unidirectionally
Dendrites- bidirectionally
What filaments stabilise the axon
Neuro filaments
How is cargo transported in neurones?
Kinesins
How does a kinesin motor work?
2 kinesin form a dimer to form a motor protein kinesins move from negative to positive. This is done using the hydrolysis of ATP cycling to cause them to walk.
What are kinesins attached to?
Microtubules
How are sodium channels made?
Made of one protein sequence with 4 domain each making 1/4 of the pore. Each domain has a voltage sensor, this causes re-entry loops open and close dependent on charges.
Sodium channels activation and deactivation thresholds
Activation: -50mv
Deactivation: 0mv
How are potassium channels formed?
1 protein sequence with 4 domains making a tetramer. Each domain has a voltage sensor. Re-entry loops open and close depending on voltage.
Potassium channel activation and deactivation?
Activation: 0mv
Deactivation: +50mv
How does electrical transmission occur?
Signal is passed through ions that move through tight junctions in to postsynaptic neuron.
How are tight junctions made for electrical synapses?
Made from heavy channels that are made of 6 domains each and when they line up creates a full conduit between cells
Two types of synaptic transmission?
Chemical and electrical
How does chemical synapse work?
Excitation of a neuron leads to Ca2+ release in the synaptic terminal. Ca2+ causes conformational change of a protein called synaptotagmin, this allows SNARE proteins to cause vesicles to fuse with plasma membrane releasing neurotransmitter
What protein does Ca2+ bind to in chemical synapses?
Synaptotagmin
What proteins promote vesicle fusion with plasma membrane? (Chemical synapse)
SNARE proteins
How is a synaptic signal terminated?
By diffusion or reuptake or neurotransmitters
What are major excitatory synapses?
Axo-dendritic synapse (use glutamate)
What are major inhibitory synapses?
Axo-somatic synapses that utilise GABA
Key features of glutamate receptors:
Made of four subunits to make an ion channel. Glutamate binding is on the outside. Inside binds to organising molecule PSD-95
Key features of GABA receptors:
Made of 5 subunits with glycine bonding outside. It’s an anion channel. Binds to organising molecule gephyrin.
How are synapses held together?
Neurexin and Neuroligins attach to each other holding synapse together.
