Intro To Autonomic System

Question 1

Which presynaptic receptor provides feedback inhibition of NE

Answer 1

alpha2 receptors

Question 2

Inhibition of alpha 2 receptor cause

Answer 2

Increase of NE

Question 3

Location of alpha 1 receptors

Answer 3

1. Blood vessels of skin, viscera, kidney , salivary glands

2. Most sympathetic organs (except heart)

Question 4

Location of alpha 2 receptors

Answer 4

Platelets
Vascular smooth muscles
Exocrine gland of pancreas
Never terminals
Fat cells

Question 5

Beta 1 receptor location

Answer 5

Heart - + ve chronotrophic and inotrophic

kidney- increase renin production

Question 6

Which adrenergic receptors are inhibitory(hyperpolarize)

Answer 6

Alpha 2

Beta 2

Question 7

Which receptor binds only to epinephrine

Answer 7

Beta 2

Question 8

Action of alpha 2 and G protein

Answer 8

G protein- Gi

1. constriction of vasculature
2. Inhibit lipolysis
3. Inhibit insulin secretion
4. Increase platelet aggregation
5. Inhibit transmitter release
6. Decrease secretions

Question 9

Action of beta 2receptors G protein

Answer 9

G protein- Gs

1. Dilation of bronchiole
2. Dilation of blood vessels to lund and heart
3. Lipolysis
4. Glycogenolysis
5. Decrease motility of GIT
6. Tremors of skeletal muscles
7. Relaxation of urinary bladder
8. Increase HR and force

Question 10

Where are beta 3 receptor found

Answer 10

Fat cells

Question 11

Location and function of D1 receptors

Answer 11

1. Splanchnic vessels-dilates

2. Renal vessels- dilate

Question 12

D2 receptor location and function

Answer 12

Presynaptic nerve terminals- inhibit adenylyl cyclase

Question 13

Mechanism of action of alpha 1

Answer 13

1. Ligand binds
2. Gq protein activated
3. Activates PLC
4. Hydeolyzes PIP2
5. Form DAG and IP3
6. IP3 cause increase in intracellular Ca2+
7. Ca bind calmodulin cause phosphorylation

Question 14

Mechanism of alpha 2

Answer 14

1. Activation Gi
2. Inhibits adenylyl cyclase - dec cAMP
3. activate K+ channels or inhibit voltage gates Ca2+ channels

Question 15

Beta receptor with least affinity

Answer 15

Beta 3 but is resistant to desensitization

Question 16

G protein of D1

Answer 16

Gs - activates adenylyl cyclase-increase cAMP- vasodilation of renal and splanchnic vessels

Question 17

Mechanism of D2

Answer 17

Activate Gi protein - inhibit adenylyl cyclase- dec cAMP- open K+ channels and Ca 2+ influx

Question 18

NE more potent at which receptors

Answer 18

alpha 1 and beta 3

Question 19

Phenylephrine and methoxamine have greater affinity at

Answer 19

Alpha1 more than alpha 2

Question 20

Clonidine and methylnorepinephrine greater affinity to which receptor

Answer 20

Alpha 2 greater than alpha 1

Question 21

Phenylephrine and methoxamine receptor, features, action

Answer 21

1. Alpha 1
2. Not a cathecol derivative
   not activated by COMPT
   Longer duration of action
3. Vasoconstriction

Question 22

Treat hypotension, nasal congestion and cause local mydriasis

Answer 22

Phenylephrine and methoxamine

Question 23

Milodrine acts on

Answer 23

Selective alpha 1 receptor

Question 24

Effects if alpha 1 agonist

Answer 24

1. mydriasis (ciliary muscle contact)
2. Increased BP (arterioles and veins constrict)
3. Piloerection
4. Bladder sphincters contacted

Question 25

Hypertension treatment

Answer 25

Presynaptic Alpha 2 agonist- Clonidine, guanabenz, guanfacine, methyldopa, moxonidine Feedback inhibition of NE release

Question 26

Side effects of presynaptic Alpha 1 agonist

Answer 26

1. Drug withdrawn too quickly- withdrawal symptoms- rebound hypertension 2. Dry mouth in 50%patient 3. Sexual dysfunction in males 4. Nausea 5. Dizziness 6. Sleep disturbances

Question 27

Clonidine acts on and effect

Answer 27

1. Brain stem alpha 2 receptors 2. Dec symp outflow to CVS - hypotension - bradycardia

Question 28

Clonidine acts on and effect

Answer 28

1. Brain stem alpha 2 receptors 2. Dec symp outflow to CVS - hypotension - bradycardia

Question 29

Fusion proteins

Answer 29

vSNARES- VAMPs ( synaptobrevin) | tSNARES- SNAPs (syntaxin, SNAP 25)

Question 30

Enzyme that converts Acetyl CoA +choline-> Ach

Answer 30

Choline acetyltransferase

Question 31

Where is Acetyl and choline got from

Answer 31

Acetyl CoA synthesised in mitochondria | Choline got from outside the cell transported by- choline transporter (CHT) Na dependent

Question 32

Drugs that act on CHT

Answer 32

HEMICHOLINIUMS

Question 33

Ach transported in to vesicle by

Answer 33

VAT (vesicle associated transport) driven by proton efflux

Question 34

VAT anther is blocked by

Answer 34

Vesamicol

Question 35

Ach in the vesicle is bound to

Answer 35

Negatively charged vesicular proteoglycan ( VPG)

Question 36

Ca entering the cells interested with what protein to trigger fusion

Answer 36

Ca binds with VAMPs- synaptotagmin on vesicle never

Question 37

How is Ach vesicle release blocked

Answer 37

Botulinum toxin cleaves 2aa from one or more SNARE proteins

Question 38

Converts tyrosine to dopa | And drug that invite this process

Answer 38

Tyrosine hydroxylase | Metyrosin

Question 39

Catecholamine enter vesicle through | This protein is blocked by

Answer 39

VMAT (vesicle monoamine transporter) | Reserpine

Question 40

1. Dopa is converted to dopamine by | 2. Dopamine is converted to NE by

Answer 40

1. Dopa decarboxylase | 2. Dopamine-β - hydroxylase