Unit 1-Review of ANS

8/18/2019 Unit 1-Review of ANS

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PHARMACOLOGY 2 and

THERAPEUTICS


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Topic One:Autonomic Nervous System

Learning Objective: Recall and review the principles of ANS

1. To review the organization, functional components, andphysiologic roles of the autonomic nervous system

2. To describe the synthesis, storage, release, reuptake,and metabolism of the major neurotransmitters in theautonomic nervous system


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ENTERICPARASYMPATHETIC

SYMPATHETIC


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AUTONOMIC NERVOUS SYSTEMCriteria Sympathetic

(Adrenergic)

Parasympathetic

(Cholinergic)

Anatomy Thoracolumbar Craniosacral

Length of Neurons Pre-ganglion: SHORTPost-ganglion: LONG

Pre-ganglion: LONGPost-ganglion: SHORT

Location of theGanglion

Near the spinal cord Near the target organ

Neurotransmitter Pre-ganglion: ACh

Post-ganglion: NE,Dopamine, Epinephrine(Hormone)

Pre-ganglion: ACh

Post-ganglion: ACh

Receptors Ganglion: NNTarget Organ: alpha,

beta, dopa

Ganglion: NNTarget Organ:

Muscarinic, Nicotinic


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ANS NEUROTRANSMITTERS

• Adrenergic(Sympathetic)

• Cholinergic(Parasympathetic)


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Sympathetic innervation of the adrenal medulla

acetylcholine

Adrenergic receptor

Nicotinic receptor

Adrenal medulla

Epinephrine is released into the blood

Ganglionic

neuron

Ganglionic transmitter

Neuroeffectortransmitter


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AUTONOMIC NERVOUS SYSTEM


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CHOLINERGIC TRANSMISSION

ADRENERGIC TRANSMISSION


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SYNTHESIS

STORAGE

RELEASE

TERMINATION


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uptake

uptake

SYNTHESIS

STORAGE

RELEASE

TERMINATION


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Biosynthesis & Metabolism of

Catecholamines

Tyrosine

DOPA

Dopamine

NE

Tyrosine hydroxylase

ALAAD

Dopamine β-hydroxylase

NE, Epi

MAO

Dihydroxymandelicacid

Normetanephrine (NE);Metanephrine (Epi)

3-methoxy-4-hydroxy-mandelic acid(VMA)

COMT

MAO

Biosynthesis Metabolism

Phenylethanolamine-N-methyltransferase

EPI(Adrenal medulla)

(Sympathetic nerve)

COMT


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The Alpha Receptors

http://cdn.pharmacologycorner.com/wp-content/uploads/2010/07/alpha-2-receptors-synapse.gifhttp://cdn.pharmacologycorner.com/wp-content/uploads/2010/07/alpha-1-receptors-synapse.gif


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Effects of alpha 1 receptor activation

on different tissues and systems


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Postsynaptic Alpha1 Receptors on

Vascular Smooth Muscle


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Presynaptic Alpha2 Receptors

• Alpha2 receptors also exist presynaptically

associated with nerve terminals• Activation of these receptors inhibits the release of

NE▫ NE acts at presynaptic alpha2 receptors to inhibit its own

release.


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Alpha-2 receptor activation


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Drugs affecting alpha receptors

http://cdn.pharmacologycorner.com/wp-content/uploads/2010/07/alpha_blockers_agonists.gif


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The Beta receptors


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Effect of Beta1 Receptor Activation

on the Heart


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Effect of Beta2 Receptor Activation

on Smooth Muscle

• Leads to vascular andnonvascular smoothmuscle relaxation

• Drugs that activate the beta2 receptor can be; ▫ used to treat as asthma

(by relaxing airway smoothmuscle) and

▫ premature labor (byrelaxing uterine smoothmuscle).


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Main effects of receptor activation

Adrenoceptor Main effects

1-receptor Vasoconstriction, relaxation of GI smooth

muscle, salivary secretion, and hepatic

glycogenolysis

2 –

receptor Inhibition of transmitter release (Ach andNA), platelet aggregation, contraction of

vascular smooth muscle, inhibition of insulin

release

1-receptor Increased cardiac rate and force

2 -receptor Bronchodilatation, vasodilatation, relaxation

of the visceral smooth muscle, hepatic

glycogenolysis and muscle tremor

3-receptor Lipolysis

Documents

Unit 1-Review of ANS