Lecture 6 - Synaptic Transmission II, Neurotransmitters & Receptors

Question 1

what are the 4 classes of small molecule neurotransmitters?

Answer 1

acetylcholine class
amino acid class
biogenic amine class
purine class

Question 2

what are the 5 classes of peptide neurotransmitters?

Answer 2

hypothalamic hormones
neuropeptide Y
opioid peptides
tachykinins
VIP-glucagon family

Question 3

what are the 3 classes of neurotransmitter types?

Answer 3

small molecule classes
peptide classes
gas class

Question 4

what is the neurotransmitter of the acetylcholine class?

Answer 4

acetylcholine

Question 5

where does acetylcholine act on?

Answer 5

acts on the brain, NMJ, autonomic endings, basal ganglia and the GI tract

Question 6

what are the 3 neurotransmitters of the amino acid class?

Answer 6

glutamate
GABA (Y-aminobutyric acid)
glycine

Question 7

where do the neurotransmitters of the amino acid class act on?

Answer 7

acts on the brain, spinal cord and the retina

Question 8

what are the 5 neurotransmitters of the biogenic amine class?

Answer 8

adrenaline
noradrenaline
dopamine
serotonin
histamine

Question 9

where do the neurotransmitters of the biogenic amine class act on?

Answer 9

acts on the brain, spinal cord and sympathetic endings

Question 10

what are the 2 neurotransmitters of the purine class?

Answer 10

ATP

adenosine

Question 11

where does the neurotransmitters of the purine class act on?

Answer 11

acts on the brain, autonomic ganglia

Question 12

where do the neurotransmitters of the peptide class act on?

Answer 12

acts on the brain, spinal cord and pituitary gland

Question 13

what are the 2 neurotransmitters of the gas class?

Answer 13

nitric oxide

carbon monoxide

Question 14

where do the neurotransmitters of the gas class act on?

Answer 14

in low does act on the brain, spinal cord and the GI tract

Question 15

what is the function of metabotropic receptors?

Answer 15

to change metabolic signalling

Question 16

what is an example of metabotropic receptors?

Answer 16

G-protein coupled receptors

Question 17

how is the G-protein coupled receptor activated?

Answer 17

binding of a neurotransmitter activates the G-protein

Question 18

what is the function of an activated G-protein?

Answer 18

to relay intracellular messages to the G-protein subunit or intracellular messengers (effector protein) to modulate ion channels

Question 19

what is the effect of modulating ion channels in G-protein coupled receptors?

Answer 19

this results in ions channels opening and ions flowing across the membrane

Question 20

what neurotransmitter classes is a G-protein coupled receptor used for?

Answer 20

used for Ach, biogenic amines, neuropeptides and purine classes

Question 21

what are ionotropic receptors?

Answer 21

receptors that are themselves an ion channel

Question 22

where does the neurotransmitter bind on ionotropic receptors?

Answer 22

the neurotransmitter binds to the cell surface receptor because they are lipophilic and cannot cross the cell membrane

Question 23

what is the effect of a neurotransmitter binding to an ionotropic receptor?

Answer 23

binding opens the ion channels resulting in ions flowing across the membrane

Question 24

what is a ligand?

Answer 24

something that binds with a biological molecule to form a complex and produces an effect

Question 25

what is an example of a ligand?

Answer 25

a neurotransmitter

Question 26

where does the neurotransmitter bind to the ionotropic receptor?

Answer 26

the neurotransmitter binds where the ion channel is an integral part of the receptor

Question 27

when is the ion channel of an ionotropic receptor closed?

Answer 27

when a neurotransmitter (ligand) is not bound the channel is closed

Question 28

what are glutamate receptors composed of?

Answer 28

composed of 3 transmembrane domains and 4 subunits

Question 29

what is the relationship between different subunits and ion channels of glutamate receptors?

Answer 29

different subunits have different properties but can still have the same ion channels

Question 30

what are the receptor subtypes of glutamate receptors?

Answer 30

NMDA, AMPA and kainate receptors

Question 31

what are cys-loop receptors composed of?

Answer 31

composed of 4 transmembrane domains and 5 subunits

Question 32

what are cys-loop receptors?

Answer 32

ligand-gated ion channels that are activated by several different structural neurotransmitters

Question 33

what are 4 examples of neurotransmitters acting upon cys-loop receptors?

Answer 33

GABA glycine serotonin acetylcholine

Question 34

what is the relationship between cys-loop receptors and excitation/inhibition?

Answer 34

these receptors can be excitatory or inhibitory based on selectivity

Question 35

what is the effect of different subunits in cys-loop receptor subtypes?

Answer 35

creates variations in strength, response, timing and duration

Question 36

what is the most common excitatory synapse in the brain?

Answer 36

glutamate synapse

Question 37

what is the function of glial cells at glutamatergic synapses?

Answer 37

to actively participate in synaptic transmission

Question 38

what is glutamate synthesised from?

Answer 38

glutamate is synthesised from glutamine by the enzyme glutaminase

Question 39

how is glutamate packaged into vesicles?

Answer 39

to be packaged into vesicles glutamine requires energy to be pumped against its concentration gradient into glutamate vesicles by the vGLUT

Question 40

what is the vGLUT?

Answer 40

vesicular glutamate transporter

Question 41

how does the exocytosis of glutamate occur?

Answer 41

occurs through glutamate receptors on the cell surface to the postsynaptic cell

Question 42

how is any extra glutamate cleaned up?

Answer 42

excitatory amino acid transporter (EAAT) cleans up any extra glutamate released and pump it back into the glutamatergic synapse

Question 43

what are the 3 types of EAAT's (excitatory amino acid transporters)?

Answer 43

EAAT1 EAAT2 EAAT5

Question 44

what is glutamate cotransported with?

Answer 44

cotransported with Na+

Question 45

what is the relationship between metabotropic receptors and the alpha subunit?

Answer 45

the alpha subunit dissociates at the metabotropic receptor

Question 46

how does the alpha subunit dissociate?

Answer 46

by the activation of ion channels leading to changes in voltage of either depolarisation (more positive) or hyperpolarisation (more negative)

Question 47

where does alpha subunit dissociation at the metabotropic receptor occur in?

Answer 47

occurs in Na+, K+ and CI- channels in the postsynaptic cell modulated by second messengers

Question 48

what are second messengers?

Answer 48

small molecules and ions that relay signals received by cell surface receptors to effector proteins

Question 49

what are voltage-gated ion channels?

Answer 49

ion channels that open in response to depolarisation

Question 50

what are ionotropic receptors?

Answer 50

ion channels that open in response to a neurotransmitter binding

Question 51

what are metabotropic receptors?

Answer 51

can open ion channels via the activation of effector proteins