31 - Pharmacological overview of the PNS Flashcards Preview

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Flashcards in 31 - Pharmacological overview of the PNS Deck (26)
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1
Q

Experiment showing that neurotransmitters exist

A

Loewi’s experiment
Stimulated a perfused, beating heart with an electrically-stimulated vagus nerve (slows heart rate)
Perfusate from stimulated heart transferred to another beating heart, which also slowed.

2
Q
Major sites for pharmacological manipulation at the synapses 
1)
2)
3)
4)
5)
6)
7)
8)
A

1) Axonal transport
2) Synthesis
3) Storage
4) Metabolism
5) Release
6) Degradation
7) Uptake
8) Post-synaptic receptor

3
Q

Difference between autonomic and somatic nervous systems

A

Somatic is voluntary, directly innervates target from CNS.

Autonomic is involuntary, has pre-ganglionic and post-ganglionic neurons

4
Q

Parasympathetic innervation structure

A

Pre-ganglionic nerve reaches near, or to target organ.

Synapse between pre- and post-ganglionic nerves is around, or within target organ

5
Q

Sympathetic innervation structure

A

Pre-ganglionic nerve is short, reaches to sympathetic chain of ganglia, which lie beside spinal cord.
Post-ganglionic nerve is long, reaches to target organ

6
Q

ACh synthesis

A

Dietary choline joined to acetyl group, which comes from acetyl-CoA, from mitochondria.
Cholineacetyltransferase catalyses this reaction
ACh carrier places ACh into vesicle within neuron

7
Q

Noradrenaline synthesis
1)
2)
3)

A

1) Tyrosine converted to L-DOPA by tyrosine hydroxylase
2) L-DOPA converted to dopamine with DOPA decarboxylase
3) Dopamine converted to noradrenaline with dopamine beta-hydroxylase

8
Q

How do dopaminergic neurons prevent dopamine being converted to noradrenaline?

A

They lack dopamine beta-hydroxylase

9
Q

How is adrenaline synthesised?

A

Noradrenaline converted to adrenaline by PNMT

10
Q

How was it proven that neurons can release more than one type of neurotransmitter?

A

Guinea pig vas deferens had two-phase contraction when stimulated.
1st phase is ATP-mediated, 2nd is noradrenaline-mediated

11
Q

What does acetylcholineesterase do?

A

Converts ACh to acetate and choline

12
Q

How is ACh deactivated?

A

Degradation

13
Q

How is noradrenaline deactivated?

A

Reuptake

14
Q

How is noradrenaline reuptaken?

A

Two reuptake channels:
1) Neuronal, high-affinity uptake 1
2_ Extra-neuronal, low-affinity uptake 2

15
Q

Neurotransmitter always used for ganglionic transmission

A

ACh

16
Q

Neurotransmitter released onto target by parasympathetic neurons

A

ACh

17
Q

Neurotransmitter released onto target by sympathetic neurons

A

Noradrenaline (except for sweat glands and adrenals, where ACh is released)

18
Q

Neurotransmitter released by somatic nervous system

A

ACh

19
Q

ACh receptors

A

Nicotinic (Na+ channel)

Muscarinig (GPCR)

20
Q

Noradrenaline receptors

A

Alpha and beta adrenoceptors (GPCR)

21
Q

Examples of cholinoceptor antagonists
1)
2)

A

1) Atropine

2) d-Tubocurarine

22
Q

Alpha adrenoceptor agonist

A

Phenylephrine

23
Q

How can a receptor be unambiguously identified as being novel?

A

Cloning of receptor

24
Q

Nicotinic ACh receptor structure

A

5 protein pore.

2x alpha subunits, 1x beta subunit, 1x gamma subunit, 1x delta subunit

25
Q

Toxin that is a strong ACh receptor antagonist

A

Alpha-bungarotoxin (from a snake).

26
Q

How can Nicotinic ACh receptor be stained?

A

Conjugate a marker to alpha bungarotoxin

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