Anti Parkinsons

Question 1

What is Parkinson’s disease

Answer 1

Degeneration of cell bodies which decrease dopamine transmission

Question 2

What is the difference between Parkinson’s and parkinsonism

Answer 2

Parkinsonism is usually drug developed symptoms of Parkinson’s

Question 3

What are the common symptoms of Parkinson’s

Answer 3

Muscle rigidity
Tremor
Uncontrollability of voluntary movement

Question 4

Where is DA produced usually which then isn’t produced in Parkinson’s

Answer 4

Nigra substantia

Question 5

What does the nigra substantia have their terminals to for DA transmission

Answer 5

Striatum

Question 6

What is the nigra striatum system called

Answer 6

Nigro striatal pathway

Question 7

What are the other 3 pathways other than the nigra striatal pathway

Answer 7

Mesocortical

Mesolimbic

Tuberoinfundibular

Question 8

Why would decreased DA at the nigra substantia cause lower control of muscle

Answer 8

Because less DA would bind to D2 inhibitory receptors At the striatum
This usually stops firing to control voluntary movement

This causes firing down neurones to the spinal cord and causes uncontrollable voluntary control

Question 9

How is dopamine synthesised

Answer 9

Via tyrosine

Tyrosine hydroxylase

L dopa

Dopa decarboxylase

Dopamine

Question 10

Which enzyme is limiting in making dopamine

Answer 10

Tyrosine hydroxylase

Question 11

Which protein transfers DA from cytosol to vesicles

Answer 11

VMAT

Question 12

What enzyme would metabolise DA if not in vesicle

Answer 12

MAO

Question 13

Explain the steps of dopamine metabolism

Answer 13

DA

MAO metabolises it into

DOPA L

Converted to DOPA C via aldehyde dehydrogenase

Converted to HVA via catechol - O - methyl transferase

Question 14

At what point does DA become inactive

Answer 14

As DOPA L, C and HVA

Question 15

What happens when DA binds to D2 inhibitory receptors

Answer 15

Inhibits adenylate cyclase

Or can open K channels stopping firing down striatum

Question 16

What happens at D1 receptors

Answer 16

Usually stimulated adenylate cyclase (excitatory causing firing down striatum)

Until DA binds which causes decreased camp and decreased firing down striatum (inhibitory)

Question 17

Which protein reuptake DA

Answer 17

DAT protein

Question 18

Which molecule is added to treat Parkinson’s disease by increasing levels of DA (to stop firing)

Answer 18

Add L dopa intermediate

Question 19

Why would L dopa be added instead of tyrosine to treat Parkinson’s

Answer 19

Because tyrosine hydroxylase is limiting

Question 20

Which drug is given with L dopa to stop too much dopamine production

Answer 20

Carbidopa

It inhibits the rate of dopa decarboxylase

Question 21

Why can’t DA be given instead of L dopa (3 reasons)

Answer 21

It’s polar so can’t cross membrane

Also would be metabolised quickly by MAO

Also causes sympathomimetic effects like tachycardia

Question 22

Why would MAOI be used to increase DA

Answer 22

Less metabolised

More DA in the vesicles

More released

More inhibition of firing at D1 and 2

Question 23

Why type of agonists would be given to treat Parkinson’s via increase in DA effects

Answer 23

D2 receptor agonists which also mimic DA inhibition of firing down the striatum

Question 24

Why would L dopa not have anywhere to be stored in Parkinson’s

Answer 24

Neuronal body degeneration (less nigra substantia)

Question 25

What is the negative effect of D2 agonists

Answer 25

They affect the other pathways like mesolimbic and mesocortical which causes psychosis

Question 26

What is the word for drug induced parkinsonism

Answer 26

Iatrogenic Parkinsonism

Question 27

Why would anti psychotics cause Parkinsonism

Answer 27

They block D2 pathways like the nigro striatal pathway

This would increase firing down striatal and cause Parkinson symptoms