Lecture 19

Question 1

What are 3 neurotransmitter termination mechanisms

Answer 1

1. Diffusion from synaptic cleft
2. Reuptake by neurotransmitter transporters
3. Enzymatic degradation

Question 2

What targets neurotransmitter transporters

Answer 2

Therapeutic agents
Cymbalta, texapro, prozac, paxil, well butrin etc…

Question 3

Describe enzyme degradation of acetylcholine

Answer 3

Hydrolysis by achetycholinesterase
Enzyme is target of neurotoxins: organophosphate incesticudes, carbamate incesticudes, Soman and Sarin nerve gas

Question 4

What are monoamine oxidases enzymes (MAO enzymes)

Answer 4

Target for antidepressants

Question 5

What are catechol-O-methyltransferase (COMT) enzymes

Answer 5

Catecholamine (made from tyrosine) inhibitors used in treatment of Parkinson’s disease

Question 6

What are catecholamines

Answer 6

Aromatic amines that regulate stress response
Affects heartrate, BP, breathing rate, muscle strength, mental alertness

Question 7

What are examples of the catecholamines derived by tyrosine

Answer 7

1. Dopamine
2. Norepinephrine
3. Epinephrine

Question 8

What is the rate limiting enzyme of catecholamine inhibition

Answer 8

Tyrosine hydroxylase

Question 9

What does serotonin regulate

Answer 9

Mood and social behavior
Appetite and digestion
Sleep
Memory
Sexual desire

Question 10

What are the monoamines in their categories

Answer 10

Catecholamines: Dopamine, Norepinephrine, Epinephrine
Indolamine: Serotonin (5OHTryptamine), Melatonin
Histamine

Question 11

What is the use of biogenic amines

Answer 11

Talking about biological activity
function as neurotransmitters regulate physiological process and signaling molecules in the microbiota-gut-brain axis

Question 12

What is glutamate

Answer 12

Major excitatory neurotransmitter in vertebrate brain

Question 13

What is GABA

Answer 13

Gamma Amino Butyric Acid
Major inhibitory amino acid neurotransmitter in vertebrate brain
GABA a receptor —> ionotropic, gates Cl- channel
GABA b receptor —> metabotropic, gates K+ channel

Question 14

What events lead to induction of Long-term potentiation (LTP)
(Synaptic plasticity)

Answer 14

1. Glutamate binds to AMPA (not blocked) and NMDA (blocked by mg2+) receptors
2. AMPA channels open allows na+ influx
3. Depolarization from Na+ ejects Mg2+
4. Ca2+ enters through NMDA
5. Increase intracellular Ca2+ to activation of secondary messenger cascade in postsynaptic neuron
6. Long-term potentiation occurs ( memory) (strengthens synaptic connection for learning and memory)

Question 15

How does long-term potentiation work

Answer 15

brain strengthens synapses by the electrical activity of the neuron sending the signal triggering the release of glutamate, which binds to postsynaptic receptors

results in AMPA receptor density, new structural synaptic connections, and persistent activation of protein kinases

Question 16

How do asctrocytes (glia) recycle glutamate

Answer 16

Glia take up glutamate
Glutamine synthetase Converts to glutamine
glutamine transporters bring Back into presynaptic terminal
glutaminase converts to glutamate and enter vesicles to be secreted through post-glutamate receptors

Question 17

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for Acetylcholine

Answer 17

precursor: choline and acetyl CoA
rate-limiting synthesis enzyme: choline acetyltransferase
vesicular transporter: Vesicular ACh transporter
removal mechanism: degradation (acetylcholinsterase)
receptor(s) and receptor type(s): Nicotonic (ionotropic (excitatory))
Muscarinic (metabotropic)

Question 18

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for Dopamine

Answer 18

Tyrosine
Tyrosine hydroxylase (TH)
Vesicular monoamine transporter (VMAT) Reuptake (dopamine transporter)
d1-like and d2-like bothMetabotropic

Question 19

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for Norepinephrine

Answer 19

dopamine
Tyrosine hydroxylase (TH) and dopamine beta-hydroxylase
VMAT
Reuptake (norepinephrine transporter)
Alpha-adrenergic receptors and Beta-adrenergic receptors
both metabotropic

Question 20

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for Serotonin

Answer 20

Tryptophan
Tryptophan hydroxylase
VMAT
Reuptake (serotonin transporter)
5-HT3 Ionotropic
5-HT1-2;4-7 Metabotropic

Question 21

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for Glutamate

Answer 21

Glutamine
Glutaminase
Vesicular glutamate transporters
uptake into glia and neurons (excitatory amino acid transporters)
AMPA ionotropic (excitatory)
NMDA ionotropic (excitatory)
Metabotropic glutamate receptors (mGlu) metabotropic

Question 22

What are the precursor,
rate-limiting synthesis enzyme,
vesicular transporter,
removal mechanism,
receptor(s),
and receptor type(s) for GABA

Answer 22

Glutamate
Glutamic acid decarboxylase (GAD)
Vesicular GABA transporter (aka vesicular inhibitory amino acid transporter VIAAT)
uptake into glia and neurons (GABA transporter; GAT)
GABAa: ionotropic (inhibitory)
GABAb: metabotropic (inhibitory)

Question 23

Chemical breakdown of acetylcholine

Answer 23

acetylcholine -> acetylcholinesterase–> choline +acetic acid

Question 24

What do the actions of an Acetylcholine depend on

Answer 24

1. neuromuscular junctions –> ionotropic receptor
2. Synapse at the heart muscle –> metabotropic receptor

Question 25

What is the pathway of catecholamine biosynthesis

Answer 25

Phenylalanine --phenylalanine hydroxylase--> L-tyrosine -- (TH)--> L-Dopa-- (AAAD)--> dopamine -- (DBH)--> Norepinephrine --PNMT--> Epinephrine

Question 26

Monoamines vs biogenic amines

Answer 26

monoamines are defined by specific chemical structure single amine groups structures biogenic amines: describe biological activity

Question 27

What is glycine

Answer 27

inhibitory neurotransmitter in vertebrate spinal cord

Question 28

what determines if a neurotransmitter is inhibitory or excitatory

Answer 28

The receptor

Question 29

Describe glutamate receptors

Answer 29

2 excitatory ionotropic receptors: AMPA, NMDA metabotropic receptor that can be excitatory or inhibitory: mGlu 1-8

Question 30

What ion is vital for LTP

Answer 30

Ca2+

Question 31

What do glutamate receptors do on the posynaptic cell

Answer 31

glutamate binding allows cations like sodium and potassium to flow in, causing depolarization and transmitting signals

Question 32

Describe Glycine

Answer 32

inhibitory amino acid neurotransmitter Gates Cl- channel (in spinal cord)