lecture 14 - ligand gated ion channels (glutamate)

Question 1

glutamate

Answer 1

an excitatory neurotransmitter in vertebrate nervous systems
ionotropic glutamate receptors: transient opening of ion channel allowing a new influx of cations generating excitatory current.
lined with negatively charged amino acids

Question 2

the drugs that activate receptors (artificial)

Answer 2

AMPA, NMDA and kainate receptors

Question 3

glutamate vinds to AMPARs and NMDARs in the body

Question 4

NMDA receptors are more sensitive than AMPA receptors

Question 5

GluN is

Answer 5

NMDA receptors

Question 6

GluA is

Answer 6

AMPA receptors

Question 7

GluK is

Answer 7

kainate receptors

Question 8

gluRs are not working in isolation

Answer 8

they are part of an enormous and complex protein network

Question 9

ionotropic glutamate receptors (iGluRs)

Answer 9

made up of 4 subunits
three transmembrane domains

Question 10

AMPAR subunits are

Answer 10

GluA1- GluA4

Question 11

AMPAR can form homomeric or heteromeric channels

Answer 11

homomeric : 4 of same subunits
heteromeric : 2 different subunits

Question 12

flip/flop variant

Answer 12

if you maintain glutamate at receptor the current doesn’t maintain
rat eat which they close depends on flip or flop
flip variant of GluA1 lengthens the time the channels are open

Question 13

subunit composition affects calsium permeability

Answer 13

if GluA2 is present it makes the receptor impermeable to calcium

Question 14

what makes glua2 impermeable to calcium

Answer 14

DNA of glua2 codes for glutamine (Q) but this is swapped for arginine (R) by editing of the mRNA the positively charged argenine sitting in the pore renders channels containing glua2 impermeable to calcium

Question 15

kainate receptors

Answer 15

lower conductance

Question 16

NMDA receptors

Answer 16

they are calcium permeable and non specific
they mg ion wedges itself into the pore and its drawn in due to there being a negative field inside the membrane
as you depolarised the cell there’s less negative field the mg is forced out and the pore is open
the receptors require the presence of glutamate and also require the cell to be depolarised to be open
glycine, pH also affects the channel