Receptor& Substrates - common drug receptor targets Flashcards

1
Q

agonist:

A

is a substance that binds to and activates a receptor, producing the same type of physiologic response as the endogenous substrate that binds to that same receptor.

biological effect (secretion of a hormone, contraction of a muscle, activation of an enzyme, depolarization of a membrane)

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2
Q

antagonist:
(sometimes called a _________________)

A

binds to a receptor but DOES NOT produce a subsequent reaction. The antagonist blocks the agonist from binding and inhibits the subsequent reaction.

blocker or inhibitor

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3
Q

The interaction of an antagonist with a receptor can be either ________________ or ___________

A

competitive inhibition
non-competitive inhibition

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4
Q

competitive inhibition:

A

the antagonist binds to the same active site of a receptor as the endogenous substrate

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5
Q

non-competitive inhibition:

A

is when the antagonist binds to the receptor at a site other than the active site (aka allosteric site), this causes the shape of the active site to change, so the endogenous substrate cannot bind to the active site on receptor.

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6
Q

example: so with epinephrine and albuterol
which one is endogenous?
what binding site do they both have in common?

A

epinephrine = endogenous, naturally produced by body

albuterol = exogenous substrate, produced outside of the body, functions as agonist

both bind to Beta-2 receptors and elicit same adrenergic biologic response

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7
Q

The endogenous neurotransmitter acetylcholine, primarily binds to ___________ or ________ receptors

A

Muscarinic receptors
Nicotinic receptors

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8
Q

When ACh binds to muscarinic receptors, what type of response is produced?
what are those symptoms

A

parasympathetic response —————— “rest and digest system”

SLUDD: increased activity of SLUDD

salivation/lacrimation/urination/defecation(diarrhea)/digestion(peristalsis)

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9
Q

SLUDD represents a syndrome of symptoms commonly referred to as _________________

A

cholinergic symptoms = SLUDD

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10
Q

When ACh binds to Nicotinic receptors, what symptoms occur?

A

increase in BP , HR

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11
Q

What are common drug muscarinic agonists AKA “cholinergic agonists”?

what symptoms occur

A

examples: pilocarpine, bethanechol,

they also increase SLUDD symptoms.

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12
Q

A reminder - cholinergic agonists will increase __________ symptoms.

example: pilocarpine - _______

A

SLUDD

can be given systemically to alleviate dry mouth associated with other conditions like shrogens disease. It does this by enhancing ACh activity. so increasing salivation, which in this cause is a desirable outcome. But of course, all the other components of SLUDD, may come along as side effects.

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13
Q

bethanechol

A

-used to treat urinary retention (condition in which you are unable to empty all the urine from bladder

increased urination from the cholinergic agonist is a desirable outcome, but again one may experience other side effects from SLUDD

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14
Q

Drugs that are antagonists to ACh are also called ________ and going to have the ____________ effect. Which is ________

A

anticholinergics

opposite

decrease SLUDD symptoms..

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15
Q

what are the anticholinergic side effects?

A

decrease salivation/lacrimation/urination/defecation/digestion

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16
Q

atropine

A

ACh antagonist.
-used to decrease salivation pre-operatively in patients who are going to receive anesthesia

-is an antidote for the chemotherapeutic agent irinotecan (Camptosar, Onivyde)

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17
Q

oxybutynin

A

is used for overactive bladder (symptoms of urgency & incontinence)
so decreasing urination with an antagonist

18
Q

rocuronium

A

nicotine antagonist
-these drugs block the effects of ACh at those nicotinic receptors on skeletal muscle. Causing paralysis.

side effects would include decreased HR & BP

also other neuromuscular blockers

19
Q

Remember: epinephrine and norepinephrine can act at multiple sites of ____________

A

adrenergic receptors

20
Q

remember: alpha-1 adrenergic receptors are primarily located in the ______________.

Agonist activity at these receptors causes ______________ which __________

A

peripheral vascular smooth muscle

smooth muscle vasoconstriction, increases blood pressure

think of smooth muscle vasoconstriction as creating an increase in (SVR) systemic vascular resistance

21
Q

Antagonist activity at alpha-1 adrenergic receptors causes _____________

A
22
Q

alpha-2 adrenergic receptors are primarily located ________.

remember, with an excess of NE & EPi in the synaptic cleft, those NTs bind to the receptors on presynaptic neuron which ___________. With less of these NTs, it causes a

A

centrally in the brain on presynaptic neurons

signals a decrease in the release of NE & EPi is needed. - (we call this decrease in sympathetic output)

***“think of like a negative feedback loop”

with less NE and Epi being released this causes a decrease in BP and HR.

23
Q

beta-1 adrenergic receptor are primarily located in the _________.

Agonist activity at these receptors causes ____________

A

heart

increased myocardial contractility, increased cardiac output, increased heart rate

24
Q

beta-2 receptors are primarily located in the _________.

Agonist activity at these receptors causes _________

A

lungs

smooth muscle relaxation, dilation of bronchioles (bronchodilation)

25
Q

what drugs have agonist activity at alpha-1 adrenergic receptors?

what’s the effect?

A
  • phenylephrine
  • dopamine (dose-dependent) specifically high dose
    -vasopressors (NE/Epi/vasopressin/)

smooth muscle vasoconstriction = increases blood pressure

26
Q

what drugs/drug classes have antagonist activity at alpha-1 adrenergic receptors?

what’s the effect?

A

alpha-1 blockers (doxazosin/phentolamine/)

smooth muscle vasodilation = decreases blood pressure

27
Q

what drugs/drug classes have agonist activity at alpha-2 adrenergic receptors?

what’s the effect?

A

-clonidine
-brimonidine (ophthalmic)

-signals there is too much sympathetic output
-causing less release of NE and Epi, which leads too decreases in BP and decreases HR

28
Q

what drugs have antagonist activity at alpha-2 adrenergic receptors?

what’s the effect?

A
  • ergot alkaloids (dihydroergotamine)
  • yohimbine

increases BP and HR

29
Q

what drugs have agonist activity at Beta-1 adrenergic receptors?

what’s the effect?

A
  • dobutamine
    -dopamine (dose-dependent) need moderate doses to be able to target Beta -1

increases myocardial contractility. increases CO, increases HR

30
Q

what drugs have antagonist activity at Beta-1 adrenergic receptors?

what’s the effect?

A

beta-1 selective blockers ( metoprolol, etc)

decreases myocardial contractility, decreases CO, decreases HR

31
Q

what drugs have agonist activity at Beta-2 adrenergic receptors?

what’s the effect?

A

-albuterol
- terbutaline

smooth muscle relaxation, bronchodilation

32
Q

what drugs have antagonist activity at Beta-2 adrenergic receptors?

what’s the effect?

A

non-selective beta-blockers (propranolol)

bronchoconstriction, they will lower HR

33
Q

vasopressor infusions can cause extravasation

vasopressor are vessicants

A
34
Q

Dopamine

Dopamine receptors, are located in many areas of the body which includes __________

A

renal, cardiac, CNS, etc

35
Q

what is the agonist effect on dopamine receptors?

what are some common drug agonists?

A

can really vary

levodopa, pramipexole = used to improve Parkinson disease symptoms

36
Q

what drugs/drug classes have antagonist activity at dopamine receptors?

A

1st generation antipsychotics, metoclopramide

these drugs can worsen Parkinson disease symptoms

37
Q

Serotonin

Serotonin receptors, are located in many areas of the body which includes __________

A

including GI, psychiatric, CNS, antiplatelets

38
Q

what is the agonist effect on serotonin receptors?

what are some common drug agonists?

A

triptans (sumatriptan), improve migraines

39
Q

what drugs/drug classes have antagonist activity at serotonin receptors?

what are the effects?

A
  • 5HT-3 antagonists (ondansetron)
  • 2nd generation antipsychotics

improve nausea/vomiting, psychosis

40
Q

isoproterenol

has activity at which receptors?

A

Beta-1 and Beta-2 agonist

41
Q

carvedilol

has activity at which receptors

A

alpha-1, Beta-1 and Beta-2 antagonist

get more peripheral vasodilation because of alpha-1 antagonist effects

42
Q

norepinephrine

has activity at which receptors

A

alpha-1 and beta-1 agonist