Brainscape's Knowledge GenomeTM

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


See full index

Fundamentals of Pharmacology > Noradrenaline synthesis, release and degradation > Flashcards

Noradrenaline synthesis, release and degradation Flashcards

1
Q

what processes are regulated by the autonomic nervous system?

A

Smooth muscle tone
Cardiac rate and force
Secretion (all exo/ some endocrine)
certain metabolic processes

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

What neurotransmitters are released from sympathetic post ganglionic neurones?

A

Noradrenaline

ATP

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

What neurotransmitters are released from parasympathetic post ganglionic neurones?

A

ACh

Nitric Oxide

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

how can we interfere with adrenergic pharmacology?

A

By interrupting the synthesis of adrenaline and noradrenaline.

Drugs that inhibit enzymes that help create intermediates in their synthesis.

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

What is the rate limiting step in noradrenaline synthesis?

A

Tyrosine Hydroxylase

Modifying this allows us to have the greatest control on the rest of the metabolic synthesis so this is often the target for drugs

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

What drug inhibits tyrosine hydroxylase?

A

alpha-methyltryosine

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

What drug inhibits DOPA decarboxylase?

A

Carbidopa

drug used to treat Parkinson’s disease

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

Where are adrenaline and noradrenaline stored in the body?

A

Stored in subcellular membrane limited particles (chromaffin granules) within the adrenal glands.

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

what is the main enzyme that packages noradrenaline into vesicles?

A

VMAT - Vesicular monoamine transporter

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

what drug inhibits the VMAT transporter?

A

Reserpine
Inhibits VMAT

Not in use today due to having many side effects.

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

what are varicosities?

A

Point at which neurotransmitters are released from their vesicles

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

How are neurotransmitters released from sympathetic nerves by exocytosis?

A

Arrival of action potential causes depolarisation of varicosity
This results in opening of voltage-gated Ca2+ channels Ca2+ entry causes an increase in the concentration of free Ca2+ in the varicosity
This activates Ca2+-sensitive proteins that initiate the process of exocytosis

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

explain the autoinhibition of noradrenaline release?

A

Noradrenaline, released from sympathetic varicosities, can act locally on presynaptic receptors to inhibit its own release, and also that of ATP
Noradrenaline acts on the alpha2- adrenoreceptors

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

What other mediators can affect noradrenaline release?

A

ACh - inhibits release via muscarinic receptors, facilitates nicotinic receptors

Adenosine - Inhibits release (A1 receptors)

Opioids - Inhibits release (u-receptors)

Angiotensin II - facilitates release via AT1 receptors

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

What is morphine??

A

Important analgesic with important autonomic side effects - constipation, pupillary dilation.

These autonomic side effects are through the prejunctional inhibition of neurotransmitter release

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

how is noradrenaline terminated after release?

A
  1. uptake into sympathetic nerve terminals or other cells.

2. Degradation by intracellular enzymes

17
Q

What are the processes used in uptake of noradrenaline for its termination?

A

Neuronal

Non-neuronal

18
Q

How does neuronal uptake 1 work?

A

due to the secondary active transporter NAT.

High affinity for noradrenaline, and relatively selective.

Cotransports Na, Cl and catecholamine.

19
Q

What drugs inhibit neuronal uptake transporters?

A

cocaine
Tricyclic antidepressants (desipramine)
Phenoxybenzamine

20
Q

What effect do NAT inhibitors have?

A

enhance sympathetic activity,
Desipramine:
major action on CNS.
adverse effects - tachycardia, dysrhythmia

Cocaine:
euphoria and excitement (CNS action)
acts as a local anaesthetic
Tachycardia and increased BP

21
Q

What are the autonomic effects of taking cocaine?

A

increased heart rate
Increased blood pressure
Local vasocontriction (could lead to infarction)

22
Q

How are catecholamines degraded?

A 
via intracellular enzymes
monamine oxidase (MAO) 
Catechol-O-methyl transferase (COMT)
23
Q

What are monoamine oxidase inhibitors used for and how do they work?

A

Used to treat depression

They work by blocking MAO irreversibly leading to increased noradrenaline, dopamine and 5-HT in the brain and peripheral tissues

24
Q

What are COMT inhibitors used for?

A

Treatment of Parkinson’s disease

25
Q

what do noradrenergic neuron blocking drugs do?

A

inhibit noradrenaline release from sympathetic nerve terminals.

26
Q

What are indirectly acting sympathetic amines?

A

eg. amphetamine, ephedrine, tyramine

act by displacing noradrenaline which leaks out via NAT.

27
Q

How does non-neuronal uptake of catecholamines work?

A

Non-neuronal - smooth/cardiac muscle. endothelium

Low affinity for NAd
High maximal rate of uptake

28
Q

What substances inhibit non-neuronal uptake?

A

normetanephrine
steroid hormones
phenoxybenzamine

29
Q

What is the process of synthesis of Adrenaline?

A 
Tryosine
DOPA
Dopamine
Noradrenaline
Adrenaline

Fundamentals of Pharmacology (19 decks)

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