Lecture 13, part 1: Synthesis and Storage of Excitatory Amino Acids

Question 1

excitatory amino acids

Answer 1

glutamate and aspartate

Question 2

inhibitory amino acids

Answer 2

GABBA and glycine

Question 3

how do glutamate and aspartate differ in structure

Answer 3

glutamate has an extra CH2

Question 4

glutamate and aspartate are the most abundant free amino acids in which organ?

Answer 4

brain

Question 5

how is glutamate synthesised?

Answer 5

glycolysis and from glutamine

Question 6

what are the order of products made in glycolysis?

Answer 6

pyruvate- acetyl coa- alpha ketoglutarate- glutamate

Question 7

what is the role of glutaminase?

Answer 7

catalyses the conversion of glutamine into glutamate

Question 8

how is glutamate mostly synthesised?

Answer 8

from glutamine

Question 9

how is glutamate synthesis controlled?

Answer 9

glutamate negatively feedbacks onto glutaminase

Question 10

explain the glutamine cycle within astrocytes

Answer 10

glutamine synthetase converts glutamate into glutamine

Question 11

in order for glutamate synthesis, what enters the presynaptic terminal from glial cells?

Answer 11

glutamine

Question 12

what happens to the excess glutamate?

Answer 12

taken up by glial cells and presynaptic terminals

Question 13

why is it important that glutamate is re uptaken?

Answer 13

so that it can be converted into glutamine

Question 14

reversal of transaminase reaction and glutamate dehydrogenase produces what?

Answer 14

alpha ketoglutarate

Question 15

what are the glutamate transporters?

Answer 15

VGLUT1, 2 and 3

Question 16

describe the specificity of glutamate transporters

Answer 16

specific for L-glutamate

Question 17

what transporters allow for glutamate entry into vesicles?

Answer 17

H+ antiporters

Question 18

how is ATP important in glutamate transport?

Answer 18

energy required to create proton gradients that allow for glutamate entry into the vesicle

Question 19

VGLUT1 is mostly expressed where?

Answer 19

afferent neurons

Question 20

where is VGLUT2 mostly expressed?

Answer 20

CNS

Question 21

glutamate transporters direction of activity

Answer 21

can remove or release glutamate

Question 22

how do vesicles and transporters differ in their specificity?

Answer 22

transporters have a low specificity (except they do not transport D-Glu)

Question 23

what are excitatory amino acid transporters termed as?

Answer 23

EEAT (1-5)

Question 24

the affinity of excitatory transporters:

Answer 24

10-40 micromolar

Question 25

features of glutamate transporters

Answer 25

525-573 amino acids
6-10 transmembrane domains
55% homology
alterations seen in pathology

Question 26

where is EAAT2 found?

Answer 26

astrocytes

Question 27

where is EAAT3 found

Answer 27

neurons

Question 28

where is EAAT5 found

Answer 28

retina

Question 29

EAAT1 location

Answer 29

cortical, hippocampal and cerebellular neurons and astroglia

Question 30

EAAT4 location

Answer 30

cerebellar purkinje cells

Question 31

role of VGLULT

Answer 31

packages glutamate into vesicles

Question 32

which glutamate transporters are found in glial cells?

Answer 32

EAAT2 and EAAT1

Question 33

which glutamate transporters are post synaptic ?

Answer 33

EAAT3 and EAAT4