2. Autonomic Pharmacology Flashcards
Draw out the flow chart from sensory afferent input to final efferent output
Draw out the synthesis of NE
Phenylalanine to tyrosine (phenylalanine hydroxylase - deficiency = PKU)
Tyrosine to DOPA (Tyrosine hydroxylase)
DOPA to Dopamine (Amino acid decarboxylase)
Dopamine to NE (Dopamine-B hyroxylase)
*RLS is the first step
*NE to E occurs within the adrenal medulla
What blocks tyrosine hydroxylase?
What blocks dopamine entry into vesicles?
Metyrosine
Reserpine
How does NE enter nerve terminals?
Tyrosine enters a nerve terminal via Na channel and is converted into dopamine. Dopamine then enters a vesicle vai VMAT2 where it is converted into NE
What are the three fates of NE after being released into the synaptic cleft?
1) Binds to post-synpatic membrane
2) Binds to autoreceptor
3) Reuptake into presynaptic neuron via NET
The three autoreceptors are
- Alpha 2: Inhibits NE release
- M2: Inhibits NE release
- Angiotensin2: Stimulates NE release
How can you block NE reuptake? (i.e. NET)
Cocaine
TCA
What two enzymes metabolize NE?
Monoamine oxidase (oxidizes NE)
Cathechol-O-methyl transferase (methylates NE)
Why is taking dopamine orally not effective?
MOA and COMT are located within the liver and thus taking dopamine will result in significant metabolism
How is Ach synthesized?
Choline enters the nerve terminal via Na channels and is combined with acetyl Ca via the enzyme choline acetly transferase
What drug blocks packaging of Ach inside of vesicles?
Vesamicol
Name one toxin that stimulates Ach release and another that inhibits Ach release.
Stimulates Ach release: Black widow spider toxin (results in spastic paralysis)
Inhibits ACh release: Botulinum toxin (results in flaccid paralysis)
What causes NE and Ach to be released from their vesicles?
Depolarization resulting in Ca channels opening and Ca influx
What inhibits Ach release?
Botulism toxin
What enzyme metabolizes Ach?
Acetylcholinesterase
What are the two cholinergic receptors?
Nicotinic (ligand-channels)
Muscarinic (GPCR)
What are the adernergic receptros?
Alpha and beta
What NT is released from the CNS in
a. Somatic innervation to skeletal muscle
b. SNS innervation to organs
c. PNS innervation to organs
Somatic: Ach
SNS: Preganglion - Ach; Postganglion - NE
PNS: Preganglion - Ach; Postganglion - Ach
*Postganglion SNS release Ach only when targetting sewat glands
*Preganglion SNS release Ach (as expected) at ganglions or at the adrenal medulla to induce E formation
What receptor do each of the following hit?
a. Somatic innervation to skeletal muscle
b. SNS innervation to organs
c. PNS innervation to organs
Somatic: NM on skeletal muscle
SNS preganglion: NN at adrenal medulla or ganglion
SNS postganglion: Adrenergic (alpha/beta) at organs
SNS postganglion: M receptors at sweat glands
PNS preganglion: NN at ganglion
PNS postganglion: M receptors at organs
What effect does SNS have on the body?
Increase HR
Increase blood flow to skeletal muscles
Dilate bronchi and pupils
Sweat
What effect does PNS have on the body?
Decrease HR
Increase GI
Pupil constriction
Poop
What inhibits choline uptake into nerve terminals, which otherwise would have gone on to become Ach?
Hemicholinium
Muscarinic Receptor
*For each, name the receptor involved and the effect
Heart
- SA Node
- AV node
- Atria
- Ventricles
M2 receptor invovled
Heart
- SA Node: Decrease HR
- AV node: Decrase conduction
- Atria: Decrease contractility
- Ventricles: No effect
Muscarinic Receptor
*For each, name the receptor involved and the effect
Blood vessels
- Arterioles
- Skeletal muscle
- Veins
M3 receptor invovled
Blood vessels
- Arterioles: No effect
- Skeletal muscle: No effect
- Veins: No effect
*While there is no PNS innervation, endothelium of blood vessels contain M3 receptors which if acted on by NO, cause vasodilation
Muscarinic Receptor
*For each, name the receptor involved and the effect
Lung
- Bronchiols
- Glands
M3 receptor invovled
Lung
- Bronchiols: Contraction (bronchospasms)
- Glands: Secretion
Muscarinic Receptor
*For each, name the receptor involved and the effect
GI
- Motility/tone
- Sphincters
- Glands
M3 receptor invovled
GI
- Motility/tone: Increase
- Sphincters: Relax
- Glands: Secretion
Muscarinic Receptor
*For each, name the receptor involved and the effect
Eye
- Radial muscle (dilator pupillae)
- Circular muscle (sphincter pupillae)
- Ciliary muscle
M3 receptor invovled
Eye
- Radial muscle (dilator pupillae): No effect
- Circular muscle (sphincter pupillae): Contract (miosis)
- Ciliary muscle: Contract (accomodation near vision)
Muscarinic Receptor
*For each, name the receptor involved and the effect
Urinary bladder
- Detrusor
- Trigone/sphincter
M3 receptor invovled
Urinary bladder
- Detrusor: Contract
- Trigone/sphincter: Relax
Muscarinic Receptor
*For each, name the receptor involved and the effect
Glands
- Salivary
- Salivation
- Lacrimation
M3 receptor invovled
Glands
- Salivary: Secretion
- Salivation: Secretion
- Lacrimation: Secretion
Muscarinic Receptor
*For each, name the receptor involved and the effect
Sphincters
M3 receptor invovled
Sphincters
Relaxation except for lower esophageal (contract)
Muscarinic Receptor
*For each, name the receptor involved and the effect
Sex organ
M3 receptor invovled
Sex organ
Erection
PNS acts mainly on M2 and M3 receptors.
Which organs are associated with each?
M2 - Heart
M3 - the rest
What are the 3 receptors of the CNS
Major receptors for the CNS
- NN receptor
- Found in PNS/SNS ganglions as well as on the adrenal medulla
- Nm
- Found on skeletal muscle motor end plate which are innervated by somatic motor neurons
- M1-3
- Found on organs that are innervated by the PNS as well as sweat glands which are innervated by SNS
Where are the SNS and PNS ganglions located?
SNS: Within the paraventral chains adjacent to the
PNS: Within their target organs
What is the equation for BP and CO?
BP = TPR x CO
CO = HR x SV