19: Neurotransmitters

Question 1

Glutamate and aspartate: nt vs AA

Answer 1

Metabolic and transmitter pools are kept strictly separate

Question 2

What does NMDA stand for?

Answer 2

N-methyl-D-aspartate

Question 3

Is NMDA ligand or voltage gated?

Answer 3

Both - Mg makes it ligand gated

Question 4

Epsp of NMDA receptor vs non-NMDA

Answer 4

NMDA: longer latency and duration

Non-NMDA: relatively short onset and duration

Question 5

Two types of non-NMDA receptors

Answer 5

AMPA, Kainate

Question 6

Kainate receptor

Answer 6

Allows some Ca influx as well

Question 7

Modulatory site on AMPA receptor

Answer 7

For benzos, decreases amount of Na that can enter

Question 8

What happens in areas where there are both NMDA and non-NMDA receptors?

Answer 8

1. EAA binds both receptor types, opening both channels
2. Na flows in non-NMDA channels, but is blocked from NMDA by Mg
3. Epsp from non-NMDA -> depol
4. Mg leaves due to depol
5. Ca can enter NMDA -> longer lasting epsp

Question 9

EAAs in high doses

Answer 9

Cause damage/toxicity

Question 10

EAA uptake by glial cells

Answer 10

In glial cell, turns into glutamine, is released back into synaptic cleft for Reuptake and recycling by pre-synaptic cell

Question 11

Does EAA uptake by glial cells require energy?

Answer 11

Yes, requires ATP

Question 12

What happens when Ca enters a cell via NMDA receptor?

Answer 12

Activates calcineurin -> activates NOS -> forms NO

Question 13

Which cell types can NO act on?

Answer 13

Pre and post synaptic - its lipid soluble so it diffuses through synaptic cleft

Question 14

NO functions

Answer 14

Memory, CV and respiratory control, immunologic fxs, potent vasodilator

Question 15

Downside of NO

Answer 15

Very unstable with a 5 second half life, produces free radicals

Question 16

monoamine class

Answer 16

All nts created by modifying a single AA

Question 17

Rate limiting step of Tyrosine -> epi

Answer 17

Tyrosine -> L-dopa via tyrosine hydroxylase

Question 18

What enzyme converts norep to epi

Answer 18

PNMT

Question 19

VMAT1 and 2

Answer 19

Vesicular monoamine transporters to move epi into vesicles

Question 20

Reserpine

Answer 20

Inhibits VMAT 1 and 2

Question 21

MAO

Answer 21

Monoamine oxidase, on mito surface

Question 22

COMT

Answer 22

Catechol-o-methyl transferase

Question 23

Polymorphisms in COMT

Answer 23

Increased risk of depression and anxiety

Question 24

What does 5HT stand for

Answer 24

5-hydroxy-tryptophan

Question 25

DAO

Answer 25

Diamine oxidase

Question 26

What does GABA stand for

Answer 26

y-amino butyric acid

Question 27

Protein that moves GABA into vesicles and those that remove GABA from synapse

Answer 27

VGAT: into vesicles GAT: removed from synapse

Question 28

GAT1 vs GAT2 location

Answer 28

GAT1: presynaptic terminal GAT2: glial cells around synapse

Question 29

What happens if GAT2 takes up GABA

Answer 29

Converted to glutamine and released into ECF for recycling

Question 30

Benzos, EtOH, and steroid affect on GABA A receptors

Answer 30

Potentiate its action -> bigger ipsp’s

Question 31

Extra-synaptic GABA A receptors

Answer 31

Possible site of action for many general anesthetics, like propofol

Question 32

Pre- vs post synaptic GABA B receptors

Answer 32

Pre: regulates nt release Post: inhibits post-synaptic cell

Question 33

What do ethanol, general anesthetics, and strychnine do to glycine receptor?

Answer 33

Ethanol and general anesthetics: potentiate | Strychnine: blocks it

Question 34

What protein stores ATP into vesicles

Answer 34

VNUT

Question 35

Where does ATP break down into ADP and then adenosine?

Answer 35

In synaptic cleft

Question 36

What does the word endorphins come form

Answer 36

Endogenous morphines

Question 37

Examples of peptide transmitters

Answer 37

Opioids, tachykinins, cholecystokinin, somatostatin

Question 38

What does pro-opiomelanocorinin form?

Answer 38

B-endorphins

Question 39

Formation of all peptide nts, including opioids

Answer 39

Standard protein synthesis in soma, transported down axon via fast axonal transport

Question 40

What are endocannabinoids derived from?

Answer 40

Membrane lipid arachidonic acid

Question 41

What is a major source of arachidonic acid in the brain?

Answer 41

2AG

Question 42

Where are CB1s located?

Answer 42

CNS neurons, largely presynaptic of neurons that release EAA and GABA

Question 43

Which receptor has 99% homologs with rat version, and is likely a critical receptor

Answer 43

CB1

Question 44

Polymorphisms in CB1

Answer 44

Obesity, ADHD, schizophrenia, depression, Parkinson’s

Question 45

FAAH

Answer 45

FA amide hydrolase, breaks down anandamide

Question 46

MAGL

Answer 46

Mono-acyl glycerol lipase, breaks down 2AG

Question 47

Two enzymes that oxidize/break down endocannabinoids

Answer 47

Cyclo-oxygenase, lipoxygenase