Block 1 Lecture 12 Flashcards
what happens if neurotransmitter concentration in synaptic cleft falls
reuptake and enzymatic breakdown occurs
are vesicles recycled
yes
what is glutamate reuptaken by?
glial cells and presynaptic cells
how does glutamate uptake occur
via EAATs
what are EAATs
-excitatory amino acid transporters
what do EAATs do
shift glutamate into the cell which causes protons to move inward and potassium to move out
what are EAATs powered by
sodium gradient
what is glutamate
a neurotransmitter
what does V-ATPase do
transports protons from cytoplasm into synaptic vesicles
what happens if a postsynaptic cell has inotropic receptors
an increase in the concentration of glutamate in synaptic cleft causes more sodium channels to be open causing postsynaptic cell to depolarize and the signal relayed in excitatory
what happens if a postsynaptic cell has metabotropic receptors
- an increase in glutamate concentration in synaptic cleft activates postsynaptic metabotropic glutamate receptors
- mGluRs are G protein coupled receptors
- glutamate binding causes GTP to exchange for GDP on the g-protein. this causes alpha subunits to dissociate from the complex and activate signaling pathways in the postsynaptic cell
- different mGluRs have different effects. the postsynaptic response may be depolarizing or hyperpolarizing
what happens in GPCR activation
- ligand binding causes GTP to exchange for GDP on the G protein
- this causes the alpha subunit to dissociate from the complex and activate pathways that bring about a cell response
- different g-alpha subunits activate different signaling pathways and are associated with different receptors
what type of response do mGluR1 and 5 have
slow excitatory
what type of response does mGluR2,3,4,6,7,8, have
slow inhibitory
what is the mechanism for glutamate reuptake
- glutamate is released
- taken up into glial cell or presynaptic cell
- if taken up by glial cell -> glutamate -> glutamine
- exported back to presynaptic cell
- packaged into vesicle to leave
