P6: Parkinson's Disease Flashcards
(63 cards)
what type of disease is Parkinson Disease
neurodegenerative
what % of the population over 60 has Parkinson Disease
1%
what are the classic symptoms of Parkinson Disease (4)
- rigidity
- resting tremor of hands
- bradykinesia
- postural instability
what is bradykinesia
slow movement
what is the primary cause of Parkinson Disease and what part of the brain is affected
degeneration of dopaminergic neurons in substantia nigra
in the basal ganglia, what two neurotransmitters are in balance with one another
dopamine and acetlycholine
what happens in Parkinson’s when dopamine is decreased (directly)
Ach increases
what other NTs are affected by the depletion of dopamine (4)
- GABA
- glutamate
- 5-HT (serotonin)
- norepinephrine
what is the process of creation of dopamine (3 step process)
- tyrosine
–>
- dopa
–>
- dopamine
what enzyme transforms tyrosine into dopa
tyrosine hydroxylase
what enzyme transforms dopa into dopamine
dopa decarboxylase
will dopa cross the blood brain barrier
yes
will dopamine cross the blood brain barrier
no
what part of dopa can cross the BBB
L-hand isomer (levodopa)
what is the rationale for levopoa therapy (3)
- attempt to increase dopamine content in the basal ganglia
- direct administration of dopamine ineffective because dopamine can’t cross the BBB
- must provide precursor to dopamine (levodopa (L-DOPA))
what does the BBB divide
cerebral capillary and cerebral tissue
what is the role of the BBB
be selective on what can and can’t reach the brain
once L-DOPA crosses the BBB, what enzyme converts it to dopamine
DOPA decarboxylase
what is the problem with DOPA decarboxylase
it’s found in the blood stream and brain.. L-DOPA needs to be converted to dopamine in the brain, not the blood.. means we need another drug to protect it until it can reach the brain (carbidopa)
what drug is a protective drug that is often given with L-DOPA
carbidopa
brain or blood stream:
90% of L-DOPA is converted to dopamine here
the blood stream
mechanism of carbidopa
inhibits dopa decarboxylase (prevents premature conversion)
what two things are often included in the same pill
l-dopa and carbidopa
side effects of L-Dopa therapy (5)
- GI irritation
- hypotension
- psychotropic, behavioral effects
- dyskinesias
- “freezing” of gait