Neurotransmitters

Question 1

What is the primary excitatory neurotransmitter?

Answer 1

Glutamate

Question 2

What enzyme catalyzes the reaction of α-ketoglutarate to glutamate?

Answer 2

glutamate dehydrogenase

Question 3

How is glutamate synthesized?

Answer 3

α-ketoglutarate (NADPH as a cofactor)

glutamine via glutaminase enzymes

Question 4

Glutamate release is a ____________ dependent process

Answer 4

Calcium

Question 5

What is an autoreceptor? What autoreceptors are specific to glutamate?

Answer 5

A receptor for the neurotransmitter released by that neuron;

mGluR2 & mGluR3

Question 6

Where are VGluTs found?

Answer 6

In the membrane of vesicles of glutamatergic neurons

Question 7

In what type of cell would you most likely find plasma membrane glutamate transporters?

Answer 7

astrocytes

Question 8

What do plasma membrane glutamate transporters co-transport along with glutamate?

Answer 8

Sodium

Question 9

The primary cell that mediates uptake of glutamate is the __________, via the _______________.

Answer 9

astroglia; glutamine-glutamate shuttle

Question 10

What are the steps of the glutamine-glutamate shuttle?

Answer 10

a) glutamate accumulated by astroglia is converted to glutamine via the enzyme glutamate synthase
b) glutamine is then released and taken up by neurons
c) glutamine within neurons is converted back to glutamate and packaged into vesicles

Question 11

What are two basic glutamate receptors?

Answer 11

Ionotropic

Metabotropic

Question 12

What are the two types of ionotropic receptors?

Answer 12

non-NMDA

NMDA

Question 13

What is the function of non-NMDA receptors? What are the two subtypes?

Answer 13

conduct mostly sodium and potassium

AMPA and kainite

Question 14

What is the function of NDMA receptors?

Answer 14

conduct calcium, sodium and potassium

Question 15

What are the properties of NDMA receptors?

Answer 15

(1) high conductance (big pipe)
(2) requires glycine as a cofactor
(3) requires membrane depolarization AND ligand binding to the receptor to open
(4) channel opens and closes slowly

Question 16

In NDMA receptors, membrane depolarization relieves the ______________.

Answer 16

Magnesium plug

Question 17

What is an example of a neuroactive lipid?

Answer 17

2-AG

Question 18

Where are the highest amounts of 2-AG found?

Answer 18

striatum
limbic cortex
hippocampus
cerebellum

Question 19

What also activates the same receptor as THC?

Answer 19

2-AG

Question 20

How does 2-AG synthesis differ from glutamate synthesis?

Answer 20

Synthesized and released simultaneously

not stored in vesicles

Question 21

2-AG is not formed unless _____ is also present and activated.

Answer 21

DGL (diacylglycerol lipase)

Question 22

How does MGL inactivate 2-AG?

Answer 22

hydrolyzes 2-AG into glycerol and arachidonic acid

Question 23

What are the physiological roles of 2-AG?

Answer 23

Functions to modulate many fundamental brain processes:
feeding
sleep
blood pressure
balance & posture
memory
mood

Question 24

What are the properties of the Cannabinoid receptor (CB1)?

Answer 24

a) G protein coupled
b) almost always presynaptic
c) inhibits the opening of calcium channels, therefore inhibits neurotransmitter release