Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHRM 825 > Sympathomimetics 6, 7 & 8 > Flashcards

Sympathomimetics 6, 7 & 8 Flashcards

1
Q

What is a monoamine?

A

Has one amino group connected to aromatic ring by a two carbon chain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are examples of monoamines?

A

Serotonin, dopamine, norepinephrine, epinephrine and histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a catecholamine?

A

Monoamine with catechol group.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are examples of catecholamines?

A

Norepinephrine, dopamine and epinephrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are catecholamines synthesized come from?

A

L-tyrosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the rate limiting step for catecholamine synthesis?

A

The enzyme tyrosine hydroxylase which will make L-tyrosine a catecholamine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is norepinephrine made?

A

Presynaptic vesicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is epinephrine made?

A

adrenal medulla by an enzyme found in the kidneys called Phenylethanolamine N-methyltransferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the functional groups of the catecholamine that allow it to bind to the adrenergic receptor?

A

Catechol, Beta hydroxyl and amine group.

At physiological pH, NE and E are 98% ionized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Of the beta receptors which are the major and minor ones?

A

Major are B1 and B2.

Minor is B3.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the difference between direct acting and indirect acting sympathomimetic agents?

A

Direct acting bind to the adrenergic receptor and show activity.
-alpha and beta agonist

Indirect acting don’t bind to the adrenergic receptor or show binding.
-amphetamines (releasers) and cocaine (reuptake inhibitors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is alpha 1 activity?

A

Gq - excitatory
Vasoconstriction when activated.

Causes pupillary dilation, midriasis.

Ejaculation

Inhibit urination and GI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is alpha 2 activity?

A

Gi/o - inhibitory

Vasoconstriction when activated

Prejunctionally inhibits NE release

In CNS decreases CV SNS input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is beta 1 activity?

A

Gs - stimulatory

activation causes cardiac stimulation

Secretion of renin, produced from aldosterone due to decreased salt or low Blood Volume which will help regulate BP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is beta 2 activity?

A

Gs- stimulatory

activation causes cardiac stimulation

Bronchodilation

Relaxation of uterine

GI inhibition

Vasodilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What receptor activity does NE have?

A

A1, B1 and A2

can’t bind B2 due to lack of methyl that epinephrine has.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What receptor activity does E have?

A

A1 + A2, B1 + B2

will favor Beta receptor over alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens as you add more methyl groups to the amine R1 group?

A

Receptor selectivity switches from alpha 1 to beta 2.

MAO activity also decreases.

19
Q

What happens when you modify the catechol ring?

A

Normal catechol results in beta over alpha selectivity.

Making the 2 hydroxyl groups in the meta position results in B2 selectivity NO COMT

Adding a meta methyl to a hydroxyl group results in B2 selectivity NO COMT

Only meta hydroxyl group results in A1 selectivity.

20
Q

What is important to know about NE?

A

Not orally available due to COMT quick metabolism. Parenteral

Can bind A1 (vasoconstriction leads to high BP) A2 and B1 (cardiac stimulation increase force and conduction) as agonist

Used as pressor (treat hypotension)

21
Q

What is important to know about E?

A

Binds all 4 adrenergic receptors
A1: (vasoconstriction leads to high BP)
B1: (cardiac stimulation increase force, rate and conduction)
B2: (vasodilation leading to fall in blood pressure and bronoconstrction)

Substrate for MAO and COMT

Many dosage forms.

Used in anaphylaxis with local anesthetics

22
Q

What is the action and clinical use of E?

A

Low [] effects B1 and B2
High [] effects a1 predominant

Clinical: acute anaphylaxis and cardiac effect with local anesthetics due to vasoconstriction.

23
Q

What does NE look like for the heart rate and BP

A

Increase in BP

Increase in HR

24
Q

What does E look like for the heart rate and BP

A

BP remains

Increase in HR

25
Q

What is important to know about dopamine?

A

Low dose:
-D1 agonist (vasodilation in renal, mesenteric and coronary arteries increasing blood flow)
-B1 agonist (Cardiac stimulation by increasing force, rate and conduction)

High dose:
-A1 agonist (vasoconstriction leading to increase in BP)
-B1 agonist (Cardiac stimulation leading to increased force, rate and conduction)

26
Q

What is different about dopamine?

A

There is no chiral carbon due to lack of Beta hydroxyl group.

Rapid metabolism.

EX: Fenoldopam selective D1 agonist for severe HTN
-vasodilator which will lower HTN

27
Q

What is the mixed B1, A1 agonist?

A

Dobutamine (Dobutrex)

Metabolized by COMT but not MAO

B1 agonist - cardiac stimulation leads to increased force, rate and conduction

A1 agonist - vasoconstriction leads to increased BP

28
Q

Where are A1 receptors found?

A

Vascular smooth muscle, GI smooth muscle, Intestinal smooth muscle, heart and liver. VASOCONSTRICTION.

Gq is stimulatory mobilizing Ca++ and activating PKC

29
Q

What are A1 agonist drugs manipulated for?

A

Nasal decongestant.
Vascular failure in shock and tachycardia

30
Q

What are A1 antagonist drugs manipulated for?

A

Hypertension
Benign prostatic hyperplasia
Pheochromocytoma

31
Q

What are the direct A1 agonist?

A

Phenylephrine (Neosynephrine)
Methoxamine (Vasoxyl)
Oxymetazoline (Visine)

32
Q

What should you know about Phenylephrine?

A

Direct A1 agonist.

Missing hydroxyl group - A1 selective now

Clinical:
Nasal decongestant
Mydriasis without cycloplegia (ciliary paralysis)
Pressor (increase BP) indirect
Vasoconstriction in regional anesthesia

MAO but no COMT

33
Q

What is the problem with Phenylephrine?

A

Has high first pass metabolism and broken down in the liver before reaching blood. Does Not reach site of action. No more effective than placebo.

34
Q

What is important about the imidazoline A1 agonist?

A

Imidazoline has resonance stability allowing the positive charge to spread over 3 atoms. This makes these molecule more basic (higher pka) than regular aliphatic amines

Partial agonist!

35
Q

What are the 2-alkyl imidazolines ?

A

Naphazoline (Privine)

Tetrahydrozoline (Visine)

Oxymetazoline (Afrin, Visine)

Local administration to promote vasoconstriction
-Nasal and ophthalmic decongestants

36
Q

What should you know about the A2 adrenergic receptor?

A

Gi/o - inhibitory (inhibit sympathetic activity)
-Inhibit adenylyl cyclase
-activate potassium channels
-inhibit calcium channels
-decrease cAMP

Found presynaptically and function as autoreceptors to inhibit sympathetic output.
-decreased neurotransmitter release

37
Q

What are A2 receptor agonist manipulated for?

A

HTN
Pain
Glaucoma

38
Q

How do A2 agonist reduce BP?

A

They reduce sympathetic output from the brain.

A2 found on brain stem (cardiovascular control center)

Inhibit NE release, decreasing HR, contractility, renin release and decrease vasoconstriction

39
Q

What is important about clonidine?

A

Has imidazoline ring so it can bind to A1.
-dichlorophenyl ring

less charged so CNS access

Many dosage forms

Use: HTN, opiate withdrawal and ADHD

40
Q

What are the side effects of clonidine?

A

Hypotension, sedation, dry mouth

41
Q

Where are B1 receptors found?

A

Heart

Increases force of contraction
Increases HR
Increases conduction velocity in AV node

Kidney

Increases renin release

Agonist:
For shock and congestive heart failure

Antagonist:
For HTN, angina, arrhythmias, CHF

42
Q

Where are B2 receptors found?

A

Smooth muscle

relaxation, especially bronchial smooth muscle

Vasodilation

Agonist
-asthma and premature labor

Antagonist
-Glaucoma (very few)

43
Q

Where are B3 receptors found?

A

Urinary bladder

relaxation and prevention of urination

Agonist:
overactive bladder

PHRM 825 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions