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Pharmacology Test 1 > Receptors > Flashcards

Receptors Flashcards

1
Q

____ ____ ____ is still the central dogma
of receptor activation

A

Lock and Key

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2
Q

The 4 superfamilies of receptors:

A
  1. Ligand-gated channels
  2. G protein coupled receptors (GPCRs)
  3. Enzyme/cytokine receptors
  4. Ligand-activated transcription factors
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3
Q

KNOW

What are:

  • located on cell surface
  • act by opening pores in the plasma membrane to allow ions to enter
  • usually composed of multiple subunits
  • usually multiple binding sites
A

Ligand-gated ion channels

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4
Q

In skeletal muscle, target of succinylcholine is a nicotinic acetylcholine receptor is an example of what type of receptor?

A

ligand-gated ion channel

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5
Q

This receptor is located on cell surface.

  • Incredibly diverse array of activators; largest mammalian gene family
  • Targets for high percentage of prescription drugs
  • Signal transduction involves small _____ ______
  • Probably operate as monomers, with some exceptions
A

G protein coupled receptors

second messengers

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6
Q

These molecules can bind to G protein receptors: (7)

A

autocoids

light

tastants

odorants

neurotransmitters

hormones

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7
Q

B-adrenergic receptor in heart is an example of:

A

G protein coupled receptor

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8
Q

Located on cell surface, activated by growth factors or cytokines

i. single polypeptide with intrinsic enzymatic activity
ii. usually tyrosine kinases or guanylate cyclase
iii. sometimes receptor lacks enzyme activity but has
docking sites for another enzymes
iv. often dimerizes on activation to cross-phosphorylate and initiate intracellular signal

A

Enzyme/cytokine receptors

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9
Q

What can bind to enzyme/cytokine receptors? (2)

A

Growth Factors
Cytokines

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10
Q

What are enzyme growth factor inhibitors? (2)

A

Monoclonal antibodies

Small molecule tyrosine kinase inhibitors

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11
Q

What receptor is located in cell nucleus, usually activated by steroids or other hydrophobic molecules

i. fairly common drug targets
ii. dimerize on binding agonist
ii. Agonist occupied dimers bind to DNA and alter gene
transcription

A

nuclear receptors

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12
Q

These receptors blocks chain of activity to follow:

A

nuclear receptors

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13
Q

What inhibitors are important in the treatment of cancer?

A

EGFR inhibitors

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14
Q

Progestin receptor is an example of:

Intracellular protein, binds estrogen, dimerizes, translocates to nucleus and alters transcription of particular genes

A

nuclear receptor

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15
Q

Sub-classification receptor types: (2)

Note: Within each super-family, receptors are classified based on the endogenous compound that binds to and activates them.

A

Adrenergic receptors: epinephrine and norepinephrine

Cholinergic receptors: acetylcholine

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16
Q

______ receptors were historically divided into alpha and beta subtypes, but pharmacologic and genome advancements show alpha-1, alpha-2, and beta receptors each have three. For a total of 9 adrenergic receptor subtypes!

What receptor is “fast”? “Slow”?

A

Adrenergic

alpha

beta

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17
Q

One would expect a ____ agonist to maximize the response curve.

A

full

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18
Q

One would expect a ____ agonist to somewhat increase the response curve.

A

partial

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19
Q

Binding of a drug to its receptor is usually a _______equilibrium

A

reversible

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20
Q

The amount of drug receptor complex formed is related to drug ______.

A

concentration or dose

21
Q

Agonists have structural features that trigger a conformational change in receptor resulting in 2nd equilibrium leading ultimately to a cellular response. True or false?

A

true

22
Q

At equilibrium, rate of association = rate of dissociation is known as:

A

Mass Action Law

23
Q

What is the equilibrium dissociate constant?

A

Kd

24
Q

How do you solve for affinity? Give formula.

A

Kd

k-1/k1

[D] * [R] / [DR]

25
Q

Know units for:

k1

k-1

kd

A

M-1*min-1

min-1

M

26
Q

The KD value is expressed in concentration units and is unique for a drug/receptor pair. It is a numerical value describing the sum of chemical bonding forces between the two. True or false?

A

true

27
Q

Fractional occupancy equation (2 forms)

A

[DR] / [Rtotal]

[D] / ( [D] + Kd)

28
Q

High Kd tells us ___ affinity.

A

low

and vice-versa

29
Q

Kd tells us:

  • the affinity between a drug and receptor
  • reflective of the chemical bonding forces
  • a unique chemical fingerprint for a drug-receptor pair
  • approximate concentration of drug that occupies 50% of receptors in a preparation
  • allows you to predict receptor occupancy for any drug concentration without knowing anything more about the receptor

Which is false and why?

A

tells us exact concentration of drug that occupies 50% of receptors

30
Q

The concentratrion of drug that occupies 50% of receptors in a preparation is___.

A

Kd

31
Q

They fully activate only a fraction of the receptors they occupy.

A

partial agonists

32
Q

When spare receptors are present the preparation is much more sensitive to agonists, and the EC50 for an agonist may be much _____ than its Kd would predict.

A

lower (more potent)

33
Q

Often a maximal response can be achieved at less than full occupancy; other times, full occupancy is necessary for a full maximal response.

This is known as the ____ _____ ____.

A

spare receptor concept

34
Q

EC50 is equal to Kd. True or false?

A

false

35
Q

EC50 is not equal to Kd because (4)

A

spare receptors

the receptor activation equilibrium (for agonists)

competition with endogenous activators

impaired drug access to receptor

36
Q

Factors affecting drug distribution: Cellular reservoirs (3)

A
  • Fat
    • lipid-soluble drugs
  • Bones/teeth
    • metals form insoluble phosphates
  • Increased Vd, biological half-life
37
Q

The rapidity of anesthesia into the brain depends on 2 factors:

A
  • Blood flow
  • Crosses bbb easily
38
Q

Propofol has termination due to distribution out of brain and blood. True or false?

A

true

39
Q

Three phases of propofol PK

Redistribution phase (~\_\_\_ min)
 Rapid metabolic clearance (~\_\_\_ min)
 Slow phase (\_\_\_\_-\_\_\_hr) elimination from poorly perfused tissues
A

3

45

3-4

40
Q

Amount of drug excreted =

       glomerular filtration
   \+  \_\_\_\_\_\_ \_\_\_\_\_\_
   -   \_\_\_\_\_\_ \_\_\_\_\_\_
A

tubular secretion

tubular reabsorption

41
Q

____ ______ (units of ml/min) is volume of plasma from which drug is fully removed per unit time.

A

Renal clearance

42
Q

GFR depends on (3)

A

plasma protein binding
volume of distribution
blood pressure and blood flow

43
Q

Only _____ drug (both non-ionized and ionized) is filtered.

A

free

44
Q

Tubular reabsorption of sodium, water, creates a _______ gradient of drug in the urine, which is also concentrated, in the ____ tubule.

A

concentration

proximal

45
Q

Drug reabsorption occurs via _______ diffusion, primarily in ____ _____ and ____ ____

A

passive

distal tubule

collecting duct

46
Q

Lipid soluble, ____ polar drugs (unmetabolized) are reabsorbed

A

less

47
Q

______ drug is ______ in urine

A

Ionized

excreted

48
Q

Therapeutic modulation of pH of the renal filtrate in drug overdose toxicity acidic drugs: enhanced excretion in ______ urine (NaHCO3)

A

alkaline

Pharmacology Test 1 (11 decks)

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