Pharmacology 1 - Intro to the ANS Flashcards

1
Q

List the targets and functions of the ANS

A
  • Eye (dilation/costriction of pupil + contraction of ciliary muscle)
  • Trachea/bronchioles
  • Glycogenolysis/ gluconeogenesis in the liver
  • Lipolysis in adipose
  • Increased renin secretion in the kidney
  • Ureters and bladder (detrusor, trigone and sphincter)
  • Salivary glands
  • Skin (piloerection/ sweating)
  • Heart
  • GI motility and spincters
  • Blood vessel dilation/constriction
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2
Q

What neurotransmitters are used in the ANS?

A
  • PNS uses ACh always
  • Sympathetic - pregnaglionic releases ACh, postganglionic nerve releases NA at effector organ/ released from adrenal medulla, only using ACh at sweat gland
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3
Q

What neurotransmitter is used by the somatic NS?

A

ACh

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4
Q

What receptors does acetylcholine bind to?

A
  • Membrane bound receptors

- Either muscarinic or nicotinic

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5
Q

Where are nicotinic receptors used?

A
  • PNS ganglia

- SNS ganglia

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6
Q

Where are muscarinic receptors used?

A
  • At effector organs
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7
Q

Describe the features of nicotinic receptors

A
  • Nicotinic used at autonomic ganglia
  • Stimulated by nicotine/acetylcholine
  • Type 1 - ionotrophic (ion channel linked) - important as it needs to be fast.
  • If manipulated will affect the whole ANS
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8
Q

Describe the features of muscarinic receptors

A
  • At all effector organs innervated by PNS and also by SNS where acetylcholine is used
  • Stimulated by muscarine/ acetylcholine (agonist)
  • Type 2 - G-protein coupled receptor - slower process
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9
Q

List the sub-types of muscarinic cholinoceptors and their uses

A
  • M1 - CNS, salivary gland, stomach (forebrain - learning/memory)
  • M2 - Cardiac (brain - inhibitory autoreceptors)
  • M3 - Exocrine, salivary glands, sweat glands and eye & smooth muscle (hypothalamus - food intake)
    [- M4 - Periphery (CNS prejunctional nerve endings - inhibitory)
  • M5 - CNS striatal dopamine release]
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10
Q

List the qualities of adrenoceptors

A
  • At all effector organs innervated by postganglionic sympathetic fibres
  • Stimulated by noradrenaline/adrenaline
  • Type 2- G-protein coupled
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11
Q

Describe the process of ACh production and release

A
  • Acetyl coA + choline makes ACh + coA (via choline acetyl transferase)
  • ACh released from vesicles following action potential and calcium influx
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12
Q

Describe the process of ACh metabolism

A
  • Converted to choline + acetate via acetylcholinesterase

- Breakdown products are then reused to make more acetylcholine

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13
Q

Describe the stages involved in noradrenaline production and release

A
  • Tyrosine to DOPA via tyrosine hydroxylase
  • DOPA to dopamine via DOPA decarboxylase
  • Dopamine to noradrenaline via dopamine B in the vesicle
  • Released from vesicles following action potential and calcium influx
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14
Q

Describe the process of Noradrenaline metabolism

A
  • Removed by transport proteins into the membrane - no enzyme in the synapse so NA stays in the synapse for a longer time
  • Metabolised in the presynaptic neuron to metabolites in the mitochondria, via Monoamine oxidase A
  • Degraded via COMT in the prostsynaptic neuron
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15
Q

What is responsible for the cephalic and gastric phase of digestion?

A

PNS

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16
Q

Does PNS or SNS have the most effect on intrinsic heart rate?

17
Q

Compare PNS and SNS divergence

A
  • PNS is localised and discrete, 1:1 ratio of pre:post ganglionic neurones
  • SNS is coordinated and very divergent, with up to 1:20 ratio of pre:postganglionic neurones
18
Q

What controls the enteric nervous system?

A
  • PNS and SNS

- Also local control via the environment of the gut

19
Q

What effect would blockade of nicotinic acetylcholine receptors have on heartrate

  • At rest
  • During exercise?
A
  • At rest heart rate would increase as PNS is inhibited

- During exercise less of a rise as SNS is in control - no nicotinic receptors involved

20
Q

List the subtypes of adrenoreceptors

A
  • a1
  • a2
  • B1
  • B3
21
Q

Where is the drug target for acetylcholine the stomach?

A
  • Muscarinic receptors at the stomach
  • In the smooth muscle/ acid releasing cells/ endocrine cells that release histamine
  • Increase contraction/ acid production/ histamine production
22
Q

Where is the drug target for noradrenaline when controlling heart rate?

A
  • B1 adrenoceptor in the nodal tissue

- Would increase heart rate

23
Q

How is adrenaline produced?

A
  • From noradrenaline via PNMT

- In chromaffin cells in the adrenal medulla

24
Q

How is adrenaline metabolised?

A

Degraded by COMT to metanephrine then to VMA (vanillylmandelic acid via monoamine oxidase)

25
Q

What is mydriasis?

A

Pupil dilation

26
Q

What is miosis?

A

Pupil constriction