AUTONOMIC PHARMACOLOGY Flashcards Preview

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Flashcards in AUTONOMIC PHARMACOLOGY Deck (77):
1

T1 - T12
L1 - L5

Sympathetic/Thoracolumbar

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CN 3,7,9,10
S2-S4

Parasympathetic
(Craniosacral)

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SYMPATHETIC (SANS)
Preganglionic fibers originate from

Thoracic (T1 -T12) segments of the cord
Lumbar (L1 -L5) segments of the cord

4

PARASYMPATHETIC (PANS)
Preganglionic motor fibers originate from

Cranial nerve nuclei III, VII, IX and X
Sacral segments (S2-S4)

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Preganglionic fibers are short and the
postganglionic fibers are long

SYMPATHETIC

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Few (prevertebral) on the anterior aspect of the
aorta

SYMPATHETIC

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Most of the ganglia are located in 2 paravertebral
chains that lie along the spinal cord

SYMPATHETIC

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Most of the ganglia are located in the organs
innervated, most distant from the spinal cord

PARASYMPATHETIC

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Preganglionic fibers are long and the
postganglionic fibers are short

PARASYMPATHETIC

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NEUROTRANSMITTERS (NTAs)
4 FEATURES

1. Synthesis
2. Storage
3. Release
4. Termination of action

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NEUROTRANSMITTERS
TERMINATION OF ACTION

By metabolism
-Monoamine oxidase (MAO)
-Cathecol-o-methly transferase (COMT)
Diffuse away from the synaptic cleft and get metabolized elsewhere

12


A nerve ending that releases acetylcholine as
the primary transmitter
Also a synapse in which acetylcholine is the
primary transmitter

CHOLINERGIC

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A nerve ending that releases norepinephrine as
the primary transmitter
Also a synapse in which norepinephrine is the
primary transmitter

ADRENERGIC

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All preganglionic fibers are

cholinergic

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All postganglionic parasympathetic fibers are

cholinergic

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A few postganglionic sympathetic fibers are

cholinergic

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Most postganglionic sympathetic fibers are

adrenergic

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Exception: Postganglionic sympathetic fibers
are

cholinergic

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Adrenal cortex and medulla
Ductless gland that functions as a ganglion
Postganglionic fibers are cholinergic

ADRENAL GLAND

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Inhibits transport/synthesis of ACh into the cell

HEMICHOLINIUM

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Inhibits storage of ACh into the vesicle

VESAMICOL

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Inhibits the release of ACh

BOTULINUM TOXIN

23

These drugs (Hemicholinium, vesamicol, botulinum toxin) are not very useful for systemic therapy
because their

effects are not sufficiently selective

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Inhibits the synthesis of NE

METYROSINE

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Inhibits the storage of NE

RESERPINE

26

These drugs (METYROSINE, RESERPINE, GUANETHEDINE, MAO I) have been used in several diseases because

they block sympathetic but not parasympathetic functions

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Inhibits release of NE

GUANETHEDINE

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Inhibits metabolism of NE

MAO I

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Other transmitter molecules in addition to the
primary agents (ACh or NE)
Contained in many autonomic nerves
Localized in the same vesicle as the primary
transmitter or in a separate population of vesicles
Involved in the modulation of synaptic
transmission

COTRANSMITTERS

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ATP
Enkephalins
VIP
Neuropeptide Y
Substance P
Somatostatin
Neurotensin

COTRANSMITTERS

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RECEPTOR CHARACTERISTICS

Also referred as cholinergic receptors
Respond to ACh and its analogs

A. CHOLINOCEPTORS

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A. CHOLINOCEPTORS
Subdivided into

1. MUSCARINIC receptors
2. NICOTINIC receptors

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A. CHOLINOCEPTORS

Respond to muscarine (an alkaloid)
Respond to ACh
Mimics the effects of parasympathetic
G-protein coupled

1. MUSCARINIC receptors

34


Located primarily on autonomic effector cells
Heart
Blood vessels
Smooth muscles
Presynaptic nerve terminals
Exocrine glands

1. MUSCARINIC receptors

35

3 subtypes of muscarinic receptors are important in peripheral autonomic
transmission

M1-nerve endings
M2-heart, some nerve endings
M3-effector cells, smooth muscle, exocrine
glands, endothelium

36

A. CHOLINOCEPTORS
2. NICOTINIC receptors

Respond to ACh
Respond to nicotine (another ACh mimic)
Do not respond to muscarine
Ligand-gated

37

A. CHOLINOCEPTORS
2. NICOTINIC receptors
2 major subtypes:

Nn-neuronal (ANS ganglia)
Nm-neuromuscular endplate (skeletal muscle)

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TYPE OF CHOLINOCEPTORS
Nerve endings
G-coupled
Increase IP3

M1

39

TYPE OF CHOLINOCEPTORS
Heart, some nerve endings
G-coupled
Decrease cAMP,
activates K+ channel

M2

40

TYPE OF CHOLINOCEPTORS
Effector cells, smooth
muscle, glands, endothelium
G-coupled
Increase IP3

M3

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TYPE OF CHOLINOCEPTORS
ANS ganglia
Ion channel
Depolarizes, evokes
action potential

Nn

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TYPE OF CHOLINOCEPTORS
Neuromuscular end plates
Ion channel
Depolarizes, evokes
action potential

Nm

43

RECEPTOR CHARACTERISTICS

Also referred as adrenergic receptors
Respond to NE
G-protein coupled

B. ADRENOCEPTORS

44

B. ADRENOCEPTORS
Subdivided into

1. ALPHA receptors
2. BETA receptors

45

ALPHA receptors
Located in

Blood vessels
Presynaptic nerve terminals
Blood platelets
Fat cells (lipocytes)
Neurons in the brain

46

ALPHA receptors
2 subtypes
effector tissues, smooth muscles, glands

ALPHA1-

47

ALPHA receptors
2 subtypes
nerve endings, some smooth
muscles

ALPHA2-

48

ADRENOCEPTORS
2. BETA receptors
Located on

Most types of smooth muscle
Cardiac muscle
Some presynaptic nerve terminal
Lipocytes
Brain

49

BETA receptors
3 major subtypes

BETA1-heart and kidney
BETA2-lungs, uterus, liver, heart
BETA3-fat or adipose tissue

50

Type of Adrenoceptor
Effector tissues, smooth muscle,glands
G-
Increase IP3
Increase Ca2+ ,causes contraction, secretion

Alpha1

51

Type of Adrenoceptor
Nerve endings, some smooth muscle
G- Decrease
cAMP
Decrease transmitter release, causes
contraction

Alpha2

52

Type of Adrenoceptor
Cardiac muscle, kidney
G-
Increase cAMP
Increase heart rate, force, increase renin release

Beta1

53

Type of Adrenoceptor
Lungs, uterus, heart
G-
Increase cAMP
Relax smooth muscle,
increase glycogenolysis,
increase HR, force

Beta2

54

Type of Adrenoceptor
Adipose cells
G-
Increase cAMP
Increase lipolysis

Beta 3

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Predominant state in any situation

CENTRAL INTEGRATION

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CENTRAL INTEGRATION

Ergotrophic (energy expenditure)
”Fight or flight” response

SYMPATHETIC

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CENTRAL INTEGRATION

Tropotrophic (energy saving)
Leading to growth
”Rest and digest

PARASYMPATHETIC

58


Principle of negative feedback control
Alpha receptors located on noradrenergic
terminals which are activated by NE and other
similar molecules
Activation diminishes further the release of NE
from these nerve endings

PRESYNAPTIC REGULATION

59

PRESYNAPTIC REGULATION

Presynaptic receptors that respond to
transmitter substances released by the
nerve endings and thereby regulate its
release

AUTORECEPTORS

60


Up- and down-regulation are known to
occur in response to decreased or
increased activation of the receptors
Up regulation (agonist)
Down regulation (antagonist)

POSTSYNAPTIC REGULATION

61

Transmission involves different mechanisms
in different segments of the ANS
Some drugs produce highly specific effects
Others drugs are much less selective in their
actions

PHARMACOLOGIC MODIFICATION OF
AUTONOMIC FUNCTION

62

PHARMACOLOGIC MODIFICATION OF
AUTONOMIC FUNCTION

Drug that block action potential
Very nonselective
Act on the process that is common to all
neurons

LOCAL ANESTHETICS

63

PHARMACOLOGIC MODIFICATION OF
AUTONOMIC FUNCTION
Drugs that act on the biochemical processes
involved in transmitter synthesis and storage
are more ----

selective

64


Promote the release of NE
Effect is sympathetic

TYRAMINE AND AMPHETAMINE

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Blocks uptake of ACh
Slows synthesis of ACh

HEMICHOLINIUM

66


Prevents storage of ACh

VESAMICOL

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Prevents release ACh

BOTULINUM TOXIN

68

Binds alpha receptors
Causes activation (agonist)

NOREPHINEPHRINE

69


Binds alpha receptors
Prevents activation (antagonist)

PHENTOLAMINE

70


Binds beta receptors
Activates adenyl cyclase (agonist)

ISOPROTERENOL

71


Binds to beta receptors
Prevents activation (antagonist)

PROPRANOLOL

72


Causes skeletal muscle contraction
(agonist)

NICOTINE

73


Prevents skeletal muscle contraction
(antagonist)

TUBOCURARINE

74


Binds muscarinic receptors
Activates (agonist)

BETANECHOL

75


Binds muscarinic recepto
Prevents activation

ATROPINE

76


Inhibits enzyme acetylcholinesterase
Prolongs and intensifies transmitter action

NEOSTIGMINE

77


Inhibits MAO
Increases stored transmitter pool

TRANYLCYPROMINE

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