Recceptors

Question 1

GPCR’s

Answer 1

G-protein coupled receptors
Gs and Gq are excitatory recepetors
Gi is an inhibitatory receptor

Question 2

Ionotropic

Answer 2

Ligand gated ion channels
Multi-subunit and heterogenous
Rapid cellular effects
Affects pharmacology and pharmacology

Question 3

Metabotropic

Answer 3

GPCR's 
Can be homo/heterodimers
Slower and more diffuse response involved in neromodulation 
Can activate 2nd messenger systems 
Can also act as auto-receptors

Question 4

Autoreceptors

Answer 4

A form of negative feedback where the neurotransmitter the receptor released can bind to that receptor and deactivate it preventing synaptic levels of that neurotransmitter getting too high.

Question 5

GABAa receptors

Answer 5

Iontropic: Cl- channel
Fast acting and inhibitory
Can be targeted by agonist muscimole and antagonist biculline
GABA binds to orthosteric site

Question 6

GABAb receptors

Answer 6

Metabotropic: heterodimer
Made up of R1 which has a venus fly trap GABA binding site while R2 traffics the receptor up to the surface

Closes Ca2+ channels presynaptically to reduce neurotransmitter release
Open K+ channels postsynaptically resulting in a slow hyperpolarisation

Targeted by GABAb agonist Baclofen

Question 7

GABAc receptors

Answer 7

Ionotropic: Cl- channel
Fast inhibitory action
Targeted by agonist GABA/muscimol and antagonist TPMPA

Question 8

NMDA recepetors

Answer 8

Ionotropic: Voltage gated Ca2+ ion channel
Usually blocked by Mg2+ but this block disappears when the cell is depolarised
Activation requires both glutamate and glycine
Antagonised by Ketamine/phenylcyclidine
Increases Glu release presynaptically via increasing Ca2+ influx

Question 9

mGlu receptors

Answer 9

Metabotropic
Slow neuromodulatory role
Gp1 receptors found presynaptically, Gp2/3 are found post synaptically
Reduces glutamate release presynaptically by decreasing Ca2+ influx

Question 10

VMAT

Answer 10

Vesicular mono amine transporter
Only present on vesicle membranes
Transports monoamines into vesicles for storage

Question 11

COMT

Answer 11

Catechol O methyl transferase
Inactivates NA/DA
Overexpression of COMT is a phenotype for schizophrenia

Question 12

MAO

Answer 12

Monoamine oxidase

Inactivates NA/DA/5HT

Question 13

DAT

Answer 13

Dopamine transporter

Present on cell surface membrane for uptake of DA from synaptic cleft

Question 14

NAT

Answer 14

Noradrenaline transporter

Present on cell surface membrane for uptake of NA from synaptic cleft

Question 15

SERT

Answer 15

Serotonin transporter

Present on cell surface membrane for uptake of 5HT from synaptic cleft

Question 16

5HT receptors

Answer 16

5HT1-7

5HT3 is ionotropic, rest are metabotropic

Question 17

NA receptors

Answer 17

Alpha 1/2 and Beta 1/2

Question 18

DA recepetors

Answer 18

D1-Gs coupled
D2-Gi-coupled
All are metabotropic

Question 19

ACh receptors

Answer 19

ACh acts on nicotinic (ionotropic) and muscarinic (metabotropic) receptors

Question 20

AChesterase

Answer 20

Acetylcholinesterase is the enzyme that inactivates ACh in the synpatic cleft to free choline and acetyl groups

Question 21

Histamine receptors

Answer 21

H1-4 are all GPCR’s

H1 receptors on C-fibres sensitise VR-1 nociceptors and respomds to histamine released by mast cells

Question 22

ASIC receptor

Answer 22

Acid sensing ion channel
Nociceptive receptor
Allows influx of Na+
Detects H+ ions at free nerve endings

Question 23

Purinergic receptors

Answer 23

Nociceptive receptor that detects ATP and high threshold mechanical stimulation (really hard hits)
Allows influx of Na+
Can also detect the ATP released by damaged cells

Question 24

Voltage gated Na+ channel (VGNa) (C-fibre associated)

Answer 24

Detects mechanical stimuli

Allows influx of Na+

Question 25

VR-1/TRPV-1/Vanilloid/Capsacin recepetor

Answer 25

Responds to H+ ions and heat Also activated by capsacin Opens to allow entry of Na+/Ca2+ and form graded potentials

Question 26

TrKA receptor

Answer 26

Responds to NGA (nerve growth factor) | Involved in nociceptor sensitisation via sensitising VGNa and VR-1 receptors

Question 27

Prostanoid receptors

Answer 27

Responds to prostaglandins | Involved in nociceptor sensitisation via sensitising BK1 and VGNa receptors

Question 28

BK2 receptors

Answer 28

Bradykinin receptor | Involved in nociceptor sensitisation via sensitising VR-1 receptors

Question 29

Mu opioid receptor

Answer 29

The only opioid receptor in the brain but also found along spine and periphery Involved in analgesia, euphoria, respiratory depression and constipation

Question 30

Delta opioid receptor

Answer 30

Only found along the spine Involved in analgesia, dysphoria and diuresis

Question 31

Kappa opioid receptor

Answer 31

Found along the spine and periphery | Invloved in analgesia and acts as a proconvulsant

Question 32

Features found in all opioid receptors

Answer 32

Gi coupled receptor Opens Ca2+/Closes K+ Decreases conversion of AMP to cAMP therefore there is less PKA