Anti-Parkinsons/ Neurodegenerative Diseases Flashcards
(46 cards)
As of now, what is the major role of drugs used to treat neurodegenerative diseases?
Retard neuronal degeneration
Neurodegenerative diseases mainly affect extrapyramidal systems. What is an example of 2 areas usually affected? What is usually spared?
Substancia Nigra, Striatum
Cortex
What is an example of a hypokinetic neurodegenerative disorder? A hyperkinetic one?
Hypo - Parkinson
Hyper - Huntingtons
What is a neurodegenerative disease involving muscle
weakness and atrophy due to degeneration of motor neurons in the spinal cord and cerebral cortex?
Amyotrophic lateral sclerosis (ALS)
What is a neurodegenerative disease characterized by
dementia due to degeneration of neurons in the hippocampus and cerebral cortex?
Alzheimers
What are three elements that may contribute to Parkinson’s disease?
Genetic predisposition
Environmental toxins
Viral Infections
What is a progressive neurological disease characterized by impaired voluntary movement and tremors at rest, bradykinesia, muscular rigidity, mask like facce and impaired speech?
Parkinson’s disease
What dopaminergic neuronal population is lost in Parkinson’s disease? How much of the population in lost before symptoms are seen? What is another hallmark of these neurons?
Nigrostriatal Dopamine Pathway
80% neuronal loss before symptoms
Lewy bodies in the surviving neurons
What is the protein that aggregates to form Lewy bodies?
alpha-Synuclein
Parkinson’s disease is considered an idiopathic disease. Why?
Because the exact cause of the disease is not known
What is the difference between Parkinsonism and Parkinson’s disease? What are 2 known drug causes of Parkinsonism?
Parkinsonism, known cause for the symptoms
Parkinson’s, no known cause for disease
Haloperidol and Chlorpromazine
Regarding the normal physiology of the basal ganglia, what is the major dopamine receptor of the direct pathway? What is the effect of dopamine on the direct pathway? What is the net effect of direct pathway activation and how?
D1 receptor
Dopamine activates the direct pathway
Facilitation of movement, inhibit GABA to thalamus
Regarding the normal physiology of the basal ganglia, what is the major dopamine receptor of the indirect pathway? What is the effect of dopamine on the indirect pathway? What is the net effect of indirect pathway activation?
D2
Dopamine inhibits the indirect pathway
Inhibition of movement
What is the effect of degeneration of basal ganglia neurons of dopamine levels? What is the effect of loss of DA on the direct pathway? Indirect pathway? On overall movement and why?
Reduction of dopamine release
Direct pathway now inhibited
Indirect pathway now activated
Movement in inhibited because of less excitatory input to cortex
There are 4 examples of drugs used to treat Parkinsons that increase dopamine synthesis. They are _
L-DOPA
L-DOPA/Carbidopa
Entacapone
Entacapone/L-DOPA/Carbidopa
There are 2 examples of drugs used to treat Parkinsons that decrease the catabolism of dopamine. They are _
Selegiline
Rasagiline
There are 4 examples of drugs used to treat Parkinsons that act as DA receptor agonists. They are _
Bromocriptine
Ropinirole
Pramipexole
Apomorphine
There are 2 examples of drugs used to treat Parkinsons that act as muscarinic antagonists. They are _
Benzotropine
Trihexyphenidyl
What is L-DOPA? What Parkinson symptoms does it treat? What is the L-DOPA wearing off effect?
Dopamine precursor that crosses BBB
Decreases rigidity and tremor
After 3-5 years, decreased effects of the medication in patients
What is the enzyme that metabolizes L-DOPA in the periphery such that only 1-3% of the drug reaches the brain?
aromatic l-amino acid decarboxylase
What is the basis of peripheral side effects of L-DOPA? What are some examples (5)?
Peripheral conversion of DA to NE
nausea, vomiting, anorexia, cardiac arrhythmias, orthostatic hypotension
What are 3 general CNS side effects of L-DOPA?
Hallucinations
Dyskinesia (invol. movements)
Mood changes
What is the medication of choice for the treatment of Parkinson’s disease? What is the mechanism? How does this drug improve the side effect profile of L-DOPA
- L-DOPA/Carbidopa
- Carbidopa blocks aromatic l-amino acid decarboxylase in the periphery, more L-DOPA reaches brain.
- Use less L-DOPA, less side effects
What is the mechanism if action of entacapone/Levodopa/Carbidopa ?
Entacapone blocks catechol-O-methyltransferase, which further decreases metabolism of L-DOPA. More L-DOPA reaches brain