Lecture 2: Membrane Bound Receptors

Question 1

Resting Membrane Potential Amount

Answer 1

-70 mV

Question 2

Excitatory

Answer 2

inside of cell approaches 0 mV

Question 3

Inhibitory

Answer 3

inside of cell becomes more negative

usually lets Cl into cell

Question 4

Orthosteric antagonist

Answer 4

binds to main binding site of receptor

can be outcompeted

Question 5

Allosteric antagonist

Answer 5

binds to accessory binding sites

Question 6

Pore blocker

Answer 6

physically obstructs the channel

Question 7

Ligand gated ion channels speed and families

Answer 7

fast
cys-loop receptors
ionotropic receptors

Question 8

Cys-Loop receptor shape

Answer 8

pentamer - up to 5 subunits

Question 9

Cys-Loop excitatory receptors

Answer 9

nicotinic acetylcholine receptors

serotonin receptors

Question 10

**Inhibitory receptors

Answer 10

Glycine

GABAa

Question 11

What obstructs the pore of ligand gated ion channel

Answer 11

second transmembrane domain of alpha subunit

Question 12

Cys-Loop receptor drugs (nicotinic and GABAa)

Answer 12

nicotinic acetylcholine receptors - nicotine, varenicline (chantix)
GABAa receptors - barbiturates, benzodiazepines, alcohol

Question 13

Glutamate receptor drugs

Answer 13

NMDA receptors - ketamine

AMPA receptors - Aniracetam

Question 14

Nicotinic Acetylcholine Receptors

Answer 14

NMJ - alpha, beta, delta, gamma
neuronal - alpha, beta
up-regulate in response to chronic nicotine (x2)

Question 15

**Desensitized state

Answer 15

higher affinity for ligand to bind

Question 16

E.g. Smoker that’s jittery

Answer 16

administer nicotine to move channel from open to desensitized

Question 17

Ionotropic glutamate receptor size, type, what do they pass?

Answer 17

tetramers, excitatory, pass Na, K ions

Question 18

IGlu receptors: NMDA can pass what ions through?

Answer 18

Ca ions

Question 19

NMDA binding sites

Answer 19

4 sites: 2 glutamate, 2 glycine, all 4 must be occupied

Question 20

Long term potentiation

Answer 20

IGlu receptors do this.

more often neuron fires, stronger the synapse (learning, memory)

Question 21

NMDA receptor blockage

Answer 21

blocked by Mg (pore blocker) at resting membrane potential, voltage dependent

Question 22

When NMDA receptor opens:

Answer 22

Ca passes through, activates CaMKII

AMPAR inserted in synapse, stronger synapse

Question 23

What are coincidence receptors?

Answer 23

NMDA receptors because you need successive activation

Question 24

G protein coupled receptor speed and classes

Answer 24

slower than ligand gated ion channels, Class A, B, C

Question 25

GPCR class A

Answer 25

adrenergic, muscarinic acetylcholine

Question 26

GPCR class B

Answer 26

parathyroid hormone

Question 27

GPCR class C

Answer 27

metabotropic glutamate, GABAb

Question 28

G alpha subunit Gas

Answer 28

activation of adenylyl cyclase, increase cAMP

Question 29

G alpha subunit Gai

Answer 29

inhibition of adenylyl cyclase, decrease cAMP

Question 30

G alpha subunit Gaq

Answer 30

activation of phospholipase C, phosphoinositol hydrolysis, increase IP3 and DAG, release of Ca from intracellular stores

Question 31

GPCRs affect:

Answer 31

enzymes, transport proteins, contractile proteins, ion channels

Question 32

How does Cholera toxin work

Answer 32

disrupts GTP to GDP path
increased GTP - high cAMP
high cAMP activates Cl ion pumps
Cl leaves cell into intestines
Na, K, HCO3 follow Cl, hyperosmolarity, water follows

Question 33

GPCR desensitization

Answer 33

if ligand bound for long time, beta arrestin tags receptor, cell internalizes receptor, drug tolerance ensues

Question 34

GPCR beta arrestin complex

Answer 34

act as protein scaffold, independent of G protein signaling