1: Intro to ANS

Question 1

What are the principal target organs of the ANS?

Answer 1

Question 2

Name two examples of organs/systems that are only innervates by the sympathetic Nervous system

Answer 2

E.g.

• Blood vessels
• Skin
• Liver
• Kidneys

Question 3

Name one example of and organ that is innervated by both, sympathetic and parasympathetic NS and describe their respective effect

Answer 3

Pupils

• SNS: dilation
• PNS: Constriction

Trachea:

• SNS: dilation
• PNS: constriction

GI:

• SNS: inhibitory (less motility and secretion)
• PNS: exitory (more motilty and secretion

Question 4

What are the neurotransmitters of the parasympathetic NS? Which receptors do they bind to?

Answer 4

PNS uses Acetlycholine (ACh) as transmitter

1. Binds to nicotinic receptors after (long) pre-ganglionic fibre
2. Binds to Muscarenic receptors after post-ganglionic fibre in target organ

(First Nicotin than mucus)

Question 5

What type of receptor is the nicotinic receptor?

Answer 5

They are Ionotropic (Type 1) receptors

Question 6

What is an Ionotropic receptor?

Answer 6

A receptor that opens/closes an ion chanel as reaction to a ligand binding

Question 7

What type or receptor is a muscarenic acetylchline receptor?

Answer 7

It is G-Protein coupled (Type 2)

Question 8

Which Neurotransmitters does the SNS use?

Answer 8

1. ACh after (short) preganglionic fibres
   
   • Noradrenaline
   • Adrenaline / Noradrenaline produced by adrenals
   • (Sometimes ACh e.g. in sweat glands)

Question 9

Which receptors does the SNS generally uses

Answer 9

1. Nicotinic ACh receptor
2. • adrenergic receptors (adrenoceptors) (Noradrenaline/Adrenaline)
   • Muscarenic (when ACh as neurotransmitter at target organ)

Question 10

Wich sub-types of Muscarenic receptors are there?

Where do they occur and what do they controll?

Answer 10

5 Sub-types

1. M1: Neural (e.g. in Forebrain for memory)
2. M2: Cardiac (to decrease heart rate and contractility force)
3. M3: Exocrine + Smooth muscle (decreased SM contration, increases secretion

4+5 less easy to classify

• M4 – Periphery: prejunctional nerve endings (inhibitory)
• M5 – Striatal dopamine release

Question 11

What does the M1 Muscarinic achetylcholine receptor do?

Answer 11

Involved in neural parts (e.g. memory in forebrain)

Question 12

Which sub-type of muscarinic acetylcholine receptor can be found primarily in the Brain?

Answer 12

M1

Question 13

Which sub-type of muscarinic acetylcholine receptor can be found primarily in the Heart?

Answer 13

M2

Question 14

Which sub-type of muscarinic acetylcholine receptor can be found primarily in exocrine glands and Smooth muscle?

Answer 14

M3

Question 15

What type of receptor are adrenoreceptors?

Answer 15

G-protein coupled receptors (Type2)

Question 16

Which questions can be asked to discribe a pharmacodinamic action of drugs?

Answer 16

1. What is the drug target?
   * e.g. a1 adrenergic receptor
2. Where is the drug target?
   * on SM tissue
3. What is the end result of the interaction?
   * Vasoconstriction

Question 17

Describe the synthesis + degradation of Acetyloecholine

Answer 17

1. Acetyle CoA + Choline combined by Choline acetyl transferase
2. Packed into vesicles + excreted when Ca2+ influx
3. Broken down by Acetylecholine esterase in Choline + Acetate
4. Reuptake into cell

Question 18

Describe the synthesis of Noradrenaline

Answer 18

1. Tyrosine —> Tyrosine Hydroxilase —>
2. DOPA —> DOPA decarboxylase —>
3. Dopamine (transported into vesicles) —> Dopamine ß hydroxylase —>
4. Noradrenaline

Question 19

How is Noradrenaline degraded?

Answer 19

Reuptaken in pre- or post-synaptic cell, degraded via

1. Monoamine oxidase A (MAO-A) (in mitochondria)
2. COMT (Catechol-O-methyltransferase)