Parkinson's Disease Flashcards
What are some symptoms of a patient suffering from Parkinson’s Disease?
blank facial expression slow, monotonous slurred speech rigidity and tremor of extremities and head forward tilt to posture reduced arm swinging short, shuffling gait
Degeneration of dopaminergic neurons projecting from the ___ ___ to the ___.
substantia nigra; striatum
Normally, activation of dopamine ___ receptors (Galpha-i) in the striatum affects ___ and ___ release.
D2; acetylcholine; GABA
Degeneration of dopaminergic neurons projecting to the striatum attenuates ___ release and leads to a loss of proper control of motor function.
dopamine
There is loss of dopaminergic input
T/F. Dopamine can cross the blood brain barrier to get to the substantia nigra.
False, L-dopa, not dopamine, can cross the blood brain barrier to get to the substantia nigra.
Why does therapy with L-dopa have the best results if obtained during the first several years of treatment?
Sometimes there is a need to diminish dose over time because of adverse effects
Patients become less responsive (more degeneration)
T/F. Generally, L-DOPA treatment is good for 3-4 years.
True.
What enzyme does carbidopa inhibit?
a PERIPHERAL dopa decarboxylase
What reaction does carbidopa affect?
the conversion of Levodopa to dopamine, this gets more drug into the CNS because dopamine does not cross the BBB.
T/F. Without carbidopa, 80% of patients experience nausea and vomiting. This is due to activation of dopamine receptors in the gut.
True.
T/F. Dopamine receptor agonists are more toxic than L-DOPA and require a neuron from substantia nigra for delivery.
False, Dopamine receptor agonists are LESS toxic than L-DOPA and DO NOT require a neuron from substantia nigra for delivery.
Match the Dopamine Receptor Agonists with its receptor of choice.
- Bromocriptine
- Pergolide
- Pramipexole
- Ropinirole
A. D1
B. D2
C. D3
1 - B
2 - A, B
3 - C
4 - B
Dopamine is metabolized by what two enzymes?
- MAO
2. COMT
What are the MAO and COMT inhibitors?
MAO = selegiline, rasagiline COMT = tolcapone, entacapone
___ is a dopamine receptor agonists that when given alone causes marked vomiting and is administered parenterally. The vomiting can be overcome by concomitant use of the anti-sickness drug ___.
Apomorphine; domperidone
Amantadine is used to treat ___, however it appears to enhance synthesis, release or reuptake of ___ from the surviving nigral neurons.
influenza; nigral
What is the algorithm for Parkinson’s disease treatment?
- dopamine agonist
- levodopa + carbidopa
- increase dose and frequency of 2
- COMT or MAO-B inhibitors and adjunt therapy
- Surgery
What condition is an electrical disturbance in the brain caused by an inherited biochemical defect or a previously healed brain injury which manifests as a seizure disorder?
epilepsy
___ and other anti-seizure drugs block high frequency firing of action potentials.
Phenytoin
T/F. Some anti-convulsants potentiate the effects of GABA to dampen synaptic nerve impulses.
True.
GABA ___ is the first step in GABA metabolism. ___ is an irreversible inhibitor of this enzyme.
tranaminase; Vigabatrin
What drug is a GABA up-take inhibitor?
Tiagabine
The binding of ___ causes the chloride channel to open leading to ___ of the cell. This affect is enhanced with the addition of ___, resulting in a greater entry of chloride ions making it more difficult to ___ and therefore ___ neural excitability.
GABA; depolarization; benzodiazepines; depolarize; reduces
What type of drug is favored by dentists in emergency treatment of seizures?
Benzodiazepines: diazepam, lorazepam, clonazepam, clorazepate, clobazam, midazolam
What type of drug binds with GABA to facilitate Cl- channel opening and although it is reasonably safe to treat epilepsy it has sedative effects that limit its utility?
Barbituates
List some barbituates.
Phenobarbital
Mephobarbital
Metharbital
Primidone
_-__ ___ channels are a low voltage activated channel that require hyperpolarization for ___. Drugs that block these channels in the ___ are effective anti-convulsants.
T-type calicum; activation; thalamus
Examples include ethosuximide, phensuximide, methsuximide, trimethadione
___ and ___ are anti-convulsant drugs that block presynaptic voltage-gated ___ channels and are thought to diminish ___ mediated neurotransmission.
Gabapentin; Pregabalin; calcium; glutamate
what drugs block the NMDA receptor?
felbamate, topiramate
