Parkinsonism Flashcards
types of Parkinsonism
- naturally occurring
- drug-induced
types of drug induced parkinsonism
- reversible: antipsychotic drugs BLOCK dopamine receptors
- irreversible: MPTP (a by-product of meperidine) DESTROYS dopaminergic neurons in the substantia nigra
neurotransmitter levels in parkonsinism
- low levels of dopamine
- high levels of ACh
theraputic strategies for parkinsonism
- drugs can only be used to treat reverible parkonsinism
- drugs are used to correct the imbalance between dopamine and ACh activity
what are the symptoms of parkinson’s disease
- tremors (shaking)
- bradykinesia (slow movement)
- muscle rigidity
- difficulty initiating movement
- reduced facial expression
- speech and cognitive impairments
what is the substantia nigra
region of the brain responsible for dopamine production
what happens to the substantia nigra in Parkinson’s disease
- undergoes progressive degeneration
- results in loss of dopamine-producing neurons
- leads to impaired motor control
what is the mechanism of toxicity for MPTP
- when MPTP enters the brain it turns into MPP+ by MAO-B
- MPP+ accumulates in dopaminergic neurons via dopamine transporter
- MPP+ causes oxidative stress, ATP depletion and neuronal cell death
what is the role of L-dopa in treating parkinson’s disease
- L-dopa is a precursor to dopamine that can cross the BBB
- it is converted to dopamine in the brain to replenish the loss of neurotransmitters
- temporarily improves motor symptoms by compensating for dopamine deficiency
what are the side effects of L-dopa
- nausea and vomitting
- dyskinesia
- hallucinations and confusion
- hypotension
- good motility then sudden freezing
how does selegiline attempt to compensate for the dopamine deficit in Parkinson’s
- an MAO-B inhibitor that prevents dopamine breakdown, prolonging its availability in the brain
how does benztropine attempt to compensate for the dopamine deficit in Parkinson’s
- an anticholenergic drug that reduces excessive ACh - helps with neurotransmitter levels and improves motor symptoms
how does ropinirole attempt to compensate for the dopamine deficit in Parkinson’s
- a dopamine agonist that directly stimulates dopamine receptos, mimicing the effects of dopamine
which drugs can cause reversible parkinsonism
haloperidol
olanzapine
