Module 5: Autonomic & Somatic Nervous System Pharm Overview

Question 1

Anatomic Classification of the SNS

Answer 1

• thoracolumbar (T1-L2)
• Preganglionic fibers:
  
  • SHORT: terminate in ganglia at paravertebral chains
  • some longer: terminate in prevertebral ganglia
    
    • i.e. in front of vertebrae
• Postganglionic fibers:
  
  • LONG: run to innervated tissues

Question 2

Anatomic Classicification of the PSNS

Answer 2

• craniosacral
• Preganglionic fibers:
  
  • LONG: terminate just outside of the target organ

Question 3

Anatomical Classification of the Enteric Nervous System

Answer 3

(ENS)

• neurons located in the walls of the GI system
• myenteric plexus
  
  • network of nerves between the layers of the muscular propria of the GI system
    
    • responsible for peristalsis among other things
    • **Regulates MOTILITY**
• submucus plexus
  
  • regulates the configuration of the luminal surface
  • **Regulates SECRETION**

Question 4

The Neurotransmitters

Answer 4

• Cholinergic:
  
  • release ACh
    
    • all preganglionic efferent and somatic fibers
    • most postganglionic parasympathetic and few sympathetic fibers
• Noradrenergic (adrenergic)
  
  • release norepinephrine (noradrenaline)
  • mostly postganglionic sympathetic fibers
• Dopaminergic
  
  • release dopamine
  • peripheral sympathetic fibers
• Nitric Oxide
• Peptides

Question 5

Drugs that Affect ACh Release

Answer 5

• Botulinum Toxin:
  
  • indications: upper motor neuron syndrome, migraine, excessive sweating, cervical dystonia, eye muscles spasm
  • enzymatic rmoval of amino acids on SNAPs and VAMPs
  • irreversibly block ACh vesicle release leads to muscle paralysis
• Black-widow venom (alpha latrotoxin)
  
  • stimulates the release of ACh and increases muscle contraction
  • when ACh is depleted you end up with muscle paralysis
  • no therapeutic application yet

Question 6

Botulinum Toxin

Answer 6

• drug that affects ACh release
• indications: upper motor neuron syndrome, migraine, excessive sweating, cervical dystonia, eye muscles spasm
• enzymatic rmoval of amino acids on SNAPs and VAMPs
• irreversibly block ACh vesicle release leads to muscle paralysis

Question 7

Black-Widow Venom (alpha latrotoxin)

Answer 7

• drug that affects ACh release
• stimulates the release of ACh and increases muscle contraction
• when ACh is depleted you end up with muscle paralysis
• no therapeutic application yet

Question 8

Fate of Neurotransmitters: Acetylcholine

Answer 8

• bind to receptors
• gets broken down by acetylcholinesterase
• very short half-life (fraction of a second)

Question 9

Fate of Neurotransmitters: Catecholamines

Answer 9

• bind to receptors
• diffuse away
• reuptake
• metabolized by enzymes

Question 10

Catecholamines

Answer 10

• dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline)
• increase heart rate, blood pressure, breathing rate, muscle strength, and mental alertness.

Question 11

Monoamine Oxidase

Answer 11

involved in the metabolism of catecholamines

Question 12

Catechol-O-Methyltransferase (COMT)

Answer 12

• involved in the metabolism of caetcholamines

Question 13

Postsynaptic Regulation of Signals

Answer 13

2 Mechanisms:

1. up or down regulation receptors
   
   1. ex: surgical denervation of skeletal muscle = proliferation of nicotinic receptors over all parts of nerve fiber
2. Controlling through electric potential
   
   1. excitatory postsynaptic potential
   2. inhibitory postsynaptic potential

Question 14

Presynaptic Regulation of Signals

Answer 14

• provide feedback via autoreceptors
  
  • stimulation of alpha 2 decreases release of NE
  • stimulateion of beta receptors facilitates release of NE
• G-proteins inhibit Ca²⁺ intake leads to inhibition of vesicular fusion
• Provide feedback via heteroreceptors
  
  • activated by substances released from other nerve cells

Question 15

Adrenergic receptors of the radial muscle of the iris

Answer 15

alpha1 = dilation

Question 16

Adrenergic receptors of the ciliary muscle of the iris

Answer 16

Beta 2

relaxation for far vision (dilation)

Question 17

Adrenergic receptors of the lacrimal glands

Answer 17

alpha 1

secretion

Question 18

Adrenergic receptors of the Sailvary glands

Answer 18

alpha 1

secretion of potassium and water

Question 19

Adrenergic receptors of the SA node of the heart

Answer 19

Beta 1 and Beta 2

increase heart rate

Question 20

Adrenergic receptors of the atrial heart

Answer 20

beta 1 and beta 2

increase contractility and conduction velocity

Question 21

Adrenergic receptors of the AV junction

Answer 21

beta 1 and beta 2

increase automaticity and propagation velocity

Question 22

Adrenergic receptors of the Purkinje system of the heart

Answer 22

beta 1 and beta 2

increase automaticity and propagation velocity

Question 23

Adrenergic receptors of the ventricles of the heart

Answer 23

beta 1 and beta 2

increase contractility

Question 24

Adrenergic receptors of the coronary arterioles

Answer 24

alpha 1, alpha 2, and beta 2

constriction and dilation

Question 25

Adrenergic receptors of the arterioles of the skin and mucosa

Answer 25

alpha 1 and alpha 2 constriction

Question 26

Adrenergic receptors of the arterioles of the skeletal muscle

Answer 26

alpha, beta 2 dilation, constriction

Question 27

Adrenergic receptors of the cerebral arterioles

Answer 27

alpha 1 constriction (slight)

Question 28

Adrenergic receptors of the pulmonary arterioles

Answer 28

alpha 1 and beta 2 constriction, dilation

Question 29

Adrenergic receptors of the mesenteric arterioles

Answer 29

alpha 1 constriction

Question 30

Adrenergic receptors of the renal arterioles

Answer 30

alpha 1, beta 1, beta 2 constriction, dilation

Question 31

Adrenergic receptors of the salivary gland arterioles

Answer 31

alpha 1 and alpha 2 constriction

Question 32

Adrenergic receptors of the veins (systemic)

Answer 32

alpha 1, alpha 2, beta 2 constriction, dilation

Question 33

Adrenergic receptors of the bronchial muscles

Answer 33

alpha 2 relaxation

Question 34

Adrenergic receptors of the bronchial glands

Answer 34

alpha 1 and beta 2 decrease secretion, increase secretion

Question 35

Adrenergic receptors of the stomach motility

Answer 35

alpha 1, alpha 2, beta 1, beta 2 decrease (usually)

Question 36

Adrenergic receptors of the stomach sphincters

Answer 36

alpha 1 contraction (usually)

Question 37

Adrenergic receptors of stomach secretion

Answer 37

alpha 2 inhibition

Question 38

Adrenergic receptors of the liver

Answer 38

alpha 1 and beta 2 glycogenolysis and gluconeogenesis

Question 39

Adrenergic receptors of the gallbladder and ducts

Answer 39

beta 2 relaxation

Question 40

Adrenergic receptors of the acini of the pancreas

Answer 40

alpha decrease secretion

Question 41

Adrenergic receptors of the islet cells of the pancreas

Answer 41

alpha 2, beta 2 decrease secretion, increase secretion

Question 42

Adrenergic receptors of the motility and tone of the intestine

Answer 42

alpha 1, alpha 2, beta 1, beta 2 decrease

Question 43

Adrenergic receptors of the intestine sphincters

Answer 43

alpha 1 contraction

Question 44

Adrenergic receptors of intestinal secretion

Answer 44

alpha 2 inhibition

Question 45

Adrenergic receptors of renin secretion in the kidney

Answer 45

alpha 1, beta 1 decrease; increase

Question 46

Adrenergic receptors of ureter motility and tone

Answer 46

Beta 1 increase

Question 47

Adrenergic receptors of the detrusor muscle of the urinary bladder

Answer 47

beta 2 relaxation

Question 48

Adrenergic receptors of the trigone and sphincter of the urinary bladder

Answer 48

alpha 1 contraction

Question 49

Adrenergic receptors of the male sex organs

Answer 49

alpha 1 ejaculation

Question 50

Adrenergic receptors of the pilomotor muscles of the skin

Answer 50

alpha 1 contraction

Question 51

Adrenergic receptors of the sweat glands

Answer 51

alpha 1 localized secretion

Question 52

Adrenergic receptors of the fat cells of the skin

Answer 52

alpha 2, beta 1, beta 2, beta 3 inhibition of lipolysis, stimulation of lypolysis

Question 53

Adrenergic receptors of the pineal gland

Answer 53

Beta melatonin synthesis