Synapse 1 Flashcards
What is the synapse?
The place where two neurons meet or come to a tissue
What are neurotransmitters contained?
Vesicles
Where to synapses develop from?
Dendritic spines
What are dendritic spines?
Knobs of neurons that can either be formed or lost
Development of pathways
How are vesicles attached to the membrane to exocytose their contents?
t and v - Snares attach onto the vesicle and pull it towards the plasma membrane
A calcium has to react with synaptotgamin to release the clamp
Where are peptide neurotransmitters stored?
Vesicles from the Golgi
Where are ACh, noradrenaline and GABA stored?
Vesicles in the terminal
What are the different steps in neurotransmitter release for ACh, noradrenaline and GABA?
Budding
Docking- NT uptake
Priming
Fusion- exocytosis
Budding of membrane
Endocytosis
What are the two types of receptors on the post-synaptic membrane?
Ionotropic- fast
Metabotropic- slow
Describe the mechanism of ionotropic receptors?
NT binds
Conformational change induced
Pore opens
Ions flow in or out
Voltage off the cell changes
What NT bind to ionotropic receptors?
ACh, GABA and glutamate
Describe the mechanism of metabotropic receptors
NT binds
Receptor connected to G-protein
Within the G-protein, GTP replaces GDP
G protein then splits and along with the GTP subunit binds to a messenger molecule
The messenger molecules then are released and cause a conformation change opening the ion channel
The GTP is then dephosphorylated by GDP-ase inactivating it
G-protein is then back to original state
Messenger then loses its concentration so doesn’t bind to ion channel so it closes
Describe the potentials created by NT?
A single EPSP response is not enough to initiate a potential
It needs to build to reach the threshold potential
What can stop the potential rising?
Inhibitory Post Synaptic Potentials
What are the difference between EPSPs and action potentials?
EPSPs do not actively propagate along the axon
EPSPs can by caused by ionotropic of metabotropic gating
Sodium and potassium ions flow through the same non-ion specific channel
EPSPS have no refractory period thus a series can summate
How are autism, schizophrenia and Alzheimer’s related to synapses?
They have all have a decrease in dendritic spine number when the symptoms increase
