Basal Ganglia Pharmacology

Question 1

Parkinsons: hyperkinetic or hypokinetic

Answer 1

hypokinetic

Question 2

Huntingons: hyperkinetic or hypokinetic

Answer 2

hyperkinetic

Question 3

What is the underlying pathology of Parkinson Disease?

Answer 3

loss of dopaminergic activity in substantia nigra pars compact:

less direct stimulation
more indirect stimulation

Question 4

Does dopamine cross BBB?

Answer 4

no

Question 5

Levodopa
specialness
how it crosses BBB
activating enzyme
orally effective

Answer 5

• progrdug
• amino acid transporter
• L-aromatic amino acid decarboxylase
• yes

Question 6

What causes systemic side effects of L-dopa?

Answer 6

L-aromatic amino acid decarboxylase is also present in GI tract

Question 7

Carbidopa function

Answer 7

inhibits peripheral breakdown of L-dopa, only present in periphery

Question 8

What is the mechanism of L-dopa?

Answer 8

activating D1 and D2 receptors

Question 9

Why does the effectiveness of L-dopa decrease with time?

Answer 9

L-aromatic amino acid decarboxylase decrease in # w/ time

Question 10

Why should one not eat before taking L-dopa?

Answer 10

L-dopa competes w/ amino acids for transport in gut

Question 11

Biggest adverse effect of L-dopa

Answer 11

dyskenesias: abnormal involuntary movements

“peak dose dyskenesia”

Question 12

Peak dose dyskenesia
Diphasic dyskinesia
Off period dystonia

Answer 12

high level in upper limbs
rising of falling–effect on lower limbs
shortly before dose due

Question 13

What is the function of COMT inhibitors?

Answer 13

inhibit COMT: enzyme that degrades dopamine

Question 14

Entacapone mechanism

Answer 14

COMT inhibitor