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2: Pharmacology > Ligand-Gated Ion Channels and G-Protein Coupled Receptors > Flashcards

Ligand-Gated Ion Channels and G-Protein Coupled Receptors Flashcards

1
Q

The largest group of transmembrane signaling proteins is __________.

A

GPCRs

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2
Q

True or False: when receptors are not bound to anything they aren’t doing anything. Why or why not?

A

False.

They are in a dynamic state, constantly shifting conformation.

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3
Q

Receptors are usually embedded in the ________ but can also be found in the _______.

A

cell membrane

cytoplasm

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4
Q

What is a ligand and what is its function?

A

a chemical messenger: a small molecule or peptide

binds to receptors and stabilizes a conformation of the receptor

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5
Q

What does a conformational change do the the receptor?

A

changes its shape which induces downstream signal transduction

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6
Q

Drugs can only _______ or _______ the body’s own regulatory molecules, not give a cell ________.

A

mimic or block

new function

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7
Q

Receptors are ________ for physiologic processes.

A

normal points of control

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8
Q

Receptor function is regulated by _______ supplied by the _______.

A

molecules

body

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9
Q

An agonist is a drug that combines with a receptor to__________ a target organ.

A

stimulate

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10
Q

An antagonist is a drug that combines with a receptor to ________ with a naturally occurring _______ or ______.

A

interfere

agonist or agonist drug

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11
Q

_________ is how drugs interact with receptors and produce varying effects.

A

Therapeutic response

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12
Q

Affinity/Potency is ________. Therefore, low potency necessitates _______.

A

how tight the drug-receptor bond is.

more drug

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13
Q

Intrinsic activity/efficacy is ________.

A

intrinsic response when drug administered that gives maximum activity

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14
Q

A ligand that binds to a receptor and activates it is called an _______.

A

agonist

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15
Q

A ligand that binds to a receptor and prevents it from inactivating is called an ________.

A

antagonist

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16
Q

An agonist works by _________.

A

stabilizing an active conformation of the receptor

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17
Q

An antagonist is designed to ________ of an agonist. Therefore, if there is no endogenous agonist, the antagonist will _________. There has to be something to _______.

A

get in the way
not have an effect
antagonize

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18
Q

An orthosteric antagonist is ________. Also called _______.

A

a ligand that blocks signaling by competing with the endogenous agonist for the main binding site of the receptor
competitive antagonist

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19
Q

An allosteric antagonist is ________. Also called ________.

A

a ligand that binds to an accessory binding site (not the main site for activation) in order to hinder the activity of an agonist
non-competitive antagonist

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20
Q

A pore blocker is a type of ________ that ________.

A

antagonist

physically obstructs the channel

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21
Q

A receptor can fluctuate between natural conformations. Some are associated with _______, while others are not.

A

pharmacological activity

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22
Q

Drugs can activate or inactivate receptors by _______ a pharmacologically significant __________ by binding to _________ or _________ site.

A

stabilizing
conformation
orthosteric
allosteric

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23
Q

Antagonists can be either ________ or ________.

A

competitive or non-competitive

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24
Q

A partial agonist weakly stabilizes _______ or stabilizes _________ which produces a ________ response than a full agonist.

A

active site
partially active state
lower

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25
Q

Inverse agonists stabilize ________ which reverses baseline receptor activity. Differ from an antagonist in that they produce an effect whether or not there is an ________ present.

A

inactive state

agonist

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26
Q

A noncompetitive agonist will ________ the _______ response of an agonist. On a Dose-Response curve the height of the curve will be ________, therefore affecting the drug’s _______ on the ______-axis.

A 
decrease
maximal
lower
efficacy
y
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27
Q

A competitive agonist will _______ amount of agonist necessary to produce a given intensity of response. Therefore the graph will shift _______, therefore affecting the drug’s ________ NOT its ______ efficacy.

A

increase
right
dose required
maximum

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28
Q

What are four types of receptors that represent 99% what our drugs work on?

A

ligand-gated ion channels
GPCRs
kinase-linked receptors (KLR)
nuclear receptors

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29
Q

Kinase-linked receptors (KLR) function by ________. They are one of the _______ types of receptors, it takes _______ because it is changing what _______ are being expressed.

A

once activated (extracellular domain), enzyme cascade on inside of cell stimulates gene trascription

slower
hours

genes

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30
Q

Nuclear receptors are located in the _______ and typically respond to ____/____. A ________ molecule or ligand binds with receptor which stimulates ________. This process takes ______.

A 
cytoplasm
steroids/thyroid hormones
lipid-soluble
gene transcription
hours
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31
Q

The fastest type of receptor is ________. They work in ________. They work by moving ions _______ to produce cellular effects.

A

ligand-gated ion channels (ionoctropic receptors)
milliseconds
against their electrochemical gradient

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32
Q

When an ionotropic receptor is opened it can result in ________ or _______ depending of the _______ of the ion and the ________ of their movement.

A

depolarization
hyper-polarization
charge
direction

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33
Q

A GPCR or _______, act slowly, on a ______ timescale because the process requires a __________ and ________. GPCR initiates chain reaction that results in ________ which triggers a _________.

A 
metabotropic receptor
second
second messenger and several steps
enzyme cascade
cellular response
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34
Q

Examples of ionotropic receptors:

A

nicotinic Ach receptor
serotonin receptor
ATP receptor

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35
Q

Examples of GPCR:

A

glutamate receptors
adrenergic receptors (alpha & beta)
GABA receptor
muscarinic Ach receptor

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36
Q

A kinase is an enzyme that does ________ which activates an _________.

A

phosphorylation

enzyme cascade

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37
Q

Example of nuclear receptors:

A

steroid receptors

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38
Q

Examples of receptor kinases:

A

insulin, growth factors, cytokine receptors

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39
Q

Structure for ligand-gated ion channels:

A

oligomeric (4-5 subunits) subunits surrounding central pore

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40
Q

Structure for GPCRs: _______. Many GPCRs exist as ______.

A

monomeric or oligomeric
7 transmembrane helices (alpha, beta, gamma subunits) w/ intracellular G-protein coupling domain, 3 extracellular loops, 3 intracellular loops
dimers

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41
Q

Structure for receptor kinases:

A

single alpha helix links extracellular receptor and intracellular kinase domain

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42
Q

Structure of nuclear receptors:

A

monumeric, w/ DNA binding and receptor binding domains

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43
Q

A GPCR is located in the __________. Effector is via a _______ or _______. It couples via ______ or ______.

A

cell membrane
channel or enzyme
G-protein or arrestin (ARR)

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44
Q

A ligand-gated ion channel is located in the _______.

Its effector is an ________. Its coupling is _______.

A

cell membrane
ion channel
direct

45
Q

Receptor kinases are located in the _______. The effector is ________. Coupling is ______.

A

cell membrane
a protein kinase
direct

46
Q

Nuclear receptors are located in the _________. Its effector is ________. Coupling occurs via _______.

A

intracellularly
gene transcription
DNA

47
Q

Cells communicate with one another via _______.

A

action potentials

48
Q

Resting cell membrane potential is overall ______ at a charge of ________.

A

negative

-70 mV.

49
Q

Excitatory means cell’s charge is approaching _____, either by letting _______ into cell or letting _______ out of cell- making the cell more _________.

A

0 mV
positive ions
negative ions
positive

50
Q

Excitatory means cell’s charge is approaching _____, either by letting _______ into cell (_______ ) - making the cell more _________.

A

0 mV
positive ions
Na+, Ca 2+, K+
positive

51
Q

Inhibitory means cell’s charge is approaching _____, either by letting _______ into cell (_____) or letting _______ out of cell.

A

negative
negative ions
Cl-
positive ions

52
Q

When the cell is in an excitatory state, it becomes ______, which opens ________ allowing _______ ions to move _______ cell via their ________.

A 
depolarized
ion channels
positive
into
electrochemical gradient
53
Q

When the cell is in an inhibitory state, it becomes ______, which opens ________ allowing _______ ions to move _________ (or ______ ions out) cell via their ________.

A 
hyperpolarized
ion channels
negative
into
positive 
electrochemical gradient
54
Q

Voltage-gated ion channels respond to a difference in __________.

A

transmembrane potential

55
Q

Nicotinc Ach/Cys-loop receptors, GABAa receptors, glycine receptors are examples of _________ ligand-gated ion channels.

A

pentamer

56
Q

NMDA receptors, glutamate receptors, AMPA receptors, Kainate receptors are examples of _______ ligand-gated channels.

A

tetramer

57
Q

_______ is an example of an NMDA (N-methyl-D-aspartate) receptor.

A

ketamine

58
Q

Ligand-gated channels are made of ________ surrounded by a central ________ which influence which ions are let through. Agonist binding ______ pore.

A

several subunits
ion pore
opens

59
Q

CYS-Loop receptors are named because of the loop formed by ________ between 2 _______ near N-terminus.

A

disulfide bonds

cysteines

60
Q

CYS-Loop receptors are made of ____ subunits around central pore.

A

5

61
Q

5 types of subunits are: _______. Receptors are made of different combinations of these types of subunits.

A

alpha, beta, gamma, delta, and epsilon.

62
Q

Examples of excitatory receptors are _______ and ______. Examples of inhibitory receptors are _______ and ________.

A

nicotinic Ach and serotonin

glycine and GABAa

63
Q

GABAa receptors control almost all of the _______ signaling in the ________.

A

inhibitory

CNS

64
Q

Cation receptors are lined with ________ while anions are lined with _______ to help with the passage of ions through the pore.

A

negative ions

positive ions

65
Q

Gating refers to _______.

A

the opening (activation) or closing (by deactivation or inactivation) of ion channels

66
Q

In agonism, ________ needed to bind to _______ of receptor which causes a conformational change in receptor allowing the pore to open and let ions in.

A

x2 ACh

2 alpha units

67
Q

________ are responsible for obstructing ion pore in a receptor.

A

Alpha sub units

68
Q

Two types of Cys-loop receptors are:

A

nicotinic acetylcholine receptors and GABAa

69
Q

3 types of glutamate receptors are:

A

NMDA receptors
AMPA receptors
Kainate

70
Q

Two examples of chemicals that work on Nicotinic Ach receptors:

A

nicotine, Varenicline (Chantix)

71
Q

Four examples of chemicals that work on GABAa receptors:

A

Ambien (zolpidem), barbituates, benzodiazepines, alcohol

72
Q

Aniracetam (cognition-enhancer) is an example of an _________.

A

AMPA receptor

73
Q

Nicotinic ACh receptors are located at the _______ and in the ______.

A

NMJ

CNS

74
Q

Nicotinic ACh receptors in the NMJ and CNS are structurally _________, which allows drugs to be designed so that _______. In the NMJ, ACh receptors contain _________ subunits while neuronal ACh receptors only contain _________ subunits. There are a total of ______ subunits.

A 
slightly different 
they affect one receptor type without affecting the other
alpha, beta, delta, gamma 
alpha and beta
5
75
Q

In the brain, NAChRs _________, increasing the number of receptors in response to chronic _________, like in ________.

A

up-regulate
nicotine
smoking

76
Q

NACHRs can either be in one of 3 states:

A

desensitized, closed or open

77
Q

A desensitized receptor _______ responsiveness when it is _________ exposed to ________.

A

decreases
repeatedly
agonist

78
Q

AMPA and Kainate receptors are a type of _________ receptor, are _________, and allows ________ ions to pass.

A

ionotropic glutamate
excitatory
Na+, K+

79
Q

NMDA receptors are a type of ________ receptor, are _______, and allows ________ ions to pass.

A

ionotropic glutamate
excitatory
Na+, K+, Ca 2+

80
Q

Ionotropic glutamate receptors are composed of _____ subunits and have a ______ structure. Each subunit has ________, the second one forms the ______.

A

4
loop
4 transmembrane domains
ion pore

81
Q

The NMDA receptor requires its _____ binding sites to be occupied in order to open. ________ for ______ and ______ for ______ (although it is usually ______).

A

4
2 for glutamate
2 for glycine
inhibitory

82
Q

Glutamate receptors experience _________, which occurs when a synapse experiences ______ activity which creates a ________ response because of the _________ of receptors due to this activity.

A

Long Term Potentiation
increased
stronger
up-regulation

83
Q

Long Term Potentiation is implicated in ________, which is the brain’s ability to _______ and ______ based on stimuli.

A

neural plasticity
adapt
change

84
Q

At resting membrane potential in NMDA receptors, the pore is blocked by ________. _________ causes it to move because it is _______- dependent.

A

Mg 2+
depolarization
voltage

85
Q

NMDA receptors are special because they allow ______ to pass, activating _______ which controls neural excitability by regulating _______ release. This leads to ________ being inserted into the synapse.

A

Ca 2+ ions
CaMKII (camkinase II)
vesicle
AMPA receptors

86
Q

AMPA receptors result in a ________ synapse because

of their role in the _______ of excitatory transmission in the CNS and plays an important role in _______.

A

stronger
majority
neural plasticity

87
Q

Coincidence detectors influence neuronal information processing by reducing ________, reducing _________, and forming associations between separate _________.

A

temporal jitter
spontaneous activity
neural events

88
Q

________ of our genome is dedicated to _______ coding.

A

3%

GPCR

89
Q

More than half of current pharmaceuticals target _________.

A

GPCRs

90
Q

There are ______ main classes of GPCR: ____, ____, and ____.

A

3

Class A, B, and C

91
Q

Examples of Class A GPCR receptors are (2):

A

adrenergic receptors, muscarinic ACh receptors

92
Q

Examples of Class B GPCR receptors are:

A

parathyroid hormone receptor

93
Q

Examples of Class C GPCR receptors are (2):

A

metabotropic glutamate receptors, GABAb receptors

94
Q

GABAa receptors function by: ________. While GABAb receptors function by: ________.

A

GABAa: postsynaptic fast inhibition, inhibition via Cl- into cell

GABAb: postsynaptic slow inhibition, pre-synaptic Ca 2+ reduction, postsynaptic inhibition via K+ ion out of cell

95
Q

G alpha s subunits activate ________ and increase _________. This has ______ effects depending on the _______ it is in. For example, in the SA node it increases ______, and _______ the smooth muscle.

A 
adenylyl cyclase
cAMP
tissue
HR
relaxes
96
Q

G alpha i subunits _______ adenylyl cyclase and ________ cAMP, it causes _______.

A

inhibit
decreases
vasoconstriction

97
Q

Adenylyl cyclase (AC) helps to convert ________ to _______.

A

ATP to cAMP

98
Q

cAMP is a ________. Which is an _______ signaling molecule, bringing in molecules and their effects to the cell because they are unable to cross _________.

A

second messenger
intracellular
cell membrane

99
Q

A first messenger is found _______ and stimulates _______ activity.

A

extracellular

intracellular

100
Q

G alpha q subunits activate _________ which hydrolyzes _________, causing an increase in _____ and _______ and ultimately a release of _______ from intracellular stores. This results in _______.

A 
phospholipase C (PLC)
phosphoinositol
IP3
DAG
Ca 2+
contraction
101
Q

IP3 and DAG are examples of __________.

A

second messengers

102
Q

A second messenger activates _________ pathways that amplify the signal and culminate with the _________ of transcription factors, inducing a ________.

A

intracellular signaling
activation or inhibition
cellular response

103
Q

Increased levels of cAMP stimulates an increase in ________, which is responsible for the transfer of ________ from ______ to _______.

A

protein kinase A (PKA)
phosphates
ATP
other molecules

104
Q

Receptors activate g proteins which target _______, which stimulate _________, which increase _______ that stimulate ________.

A

enzymes
second messengers
protein kinases
effectors

105
Q

Examples of GPCR downstream targets are (5):

A

enzymes, transport proteins, contractile proteins, hormones, and ion channels

106
Q

The _______ of a G protein-coupled receptor (GPCR) response can be described as the loss of _______ subsequent to _________ administration of an _______.

A

desensitization
response
prolonged
agonist

107
Q

Desensitization is a _______ mechanism to prevent __________ of a receptor. This is accomplished by the binding of ________ to the receptor, which tags it for _________. This causes a ______ in drug response and contributes to drug ________.

A 
protective
overstimulation
Beta-arrestin (ARR)
internalization
decrease
tolerance
108
Q

Once internalized, the GPCR-beta-ARR complex can act as ________ inside of cell. beta-ARR signaling illicits a __________ effect than normal. Decrease in GPCRs causes a ___________ in drug effect.

A

protein scaffold
different
decrease

2: Pharmacology (2 decks)

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