Parkinsons Disease (Final Exam) Flashcards
this is a clinical syndrome characterized by
- rigidity
- bradykinesia (slowness of movement and speed (or progressive hesitations/halts) as movements are continued)
- tremor and postural instability
- asymmetry
- good response to levodopa
Parkinsonism
how is Parkinsonism caused?
idiopathic
- Parkinson’s disease (PD)
toxins
- carbon disulfide, carbon monoxide, etc,
drugs
- metoclopramide, pehnothizaine, butyrophenones, reserpine and tetrabenazine
diseases
- Wilsons disease ( a genetic disorder that prevents the body from removing extra copper, causing copper to build up in the liver, brain, eyes, and other organs)
- Shy-Drager syndrome (similar to Parkinson’s)
genetics
-PARK1, PARK2, PARK5 & PARK7
- LRRK2 is the most common familial form of PD
- glucocerebrosidase mutations
others
- von Economo encephalitis (sleeping sickness)
- repeated head trauma
this is also knowns as idiopathic Parkinsonism
- a slowly progressive degenerative neurologic disorder
- selective degeneration of monoamine containing cells
- onset: middle age but can occur much earlier
Parkinsons disease (PD)
neuronal degeneration with inclusion body formation can also effect cholinergic neurons in Parkinsons disease. what are some cholinergic neurons that may be affected
- cholingeric neurons nucleus basalis of Meynert
- NE neurons of Locus Coeruleus
- serotonin neurons of Raphe nuclei
- cerebral hemispheres, spinal cord
- peripheral autonomic nervous system
begins in autonomic nervous system, spreads upwards to affect upper CNS structures. dopaminergic neurones degeneration develops midway in the disease process
Lewy body
in Parkinson’s disease is there a loss or gain of dopaminergic neurons in the substantial nigra
loss
Parkinson’s disease is a disorder of the extrapyramidal system which is
a neuronal network that help regulate movement
in parkinsons disease there is a disruption of neurotransmitter function first ID in striatum. proper balance of stratum requires a balance between these two neurotransmitters
dopamine (inhibitory) and acetylcholine (excitatory)
is a midbrain dopaminergic nucleus which has a critical role in modulating motor movement and reward functions as part of the basal ganglia circuitry
substantia nigra
what are the two theories for the causes of degeneration of the dopaminergic neurons in parkinsons disease
- increased oxidative stress caused by interactions with “complex I” or mitochondria dysfunction
- failure to degrade alpha-synuclein has been proposed at the ethology (genetic vulnerability or environemental toxins)
what are some environmental factors that increase the risk of parkinsons disease
- presticides
- rural living and drinking well water
- MPTP
what are some environmental factors that decrease the risk of parkinsons disease
- cigarette smoking
- caffeine
explain the role of MPTP in MPTP induced parkinsons
- MPTP enters the brain astrocytes and is converted to MPDP+ by MAO-B
- MDPD+ is metabolized extracellularly to MPP+ which is taken up through dopamine uptake sites on dopamine nerve terminals & concentrated in mitochondria
- the resulting disturbance of mitochondrial function can lead to neuronal death
why are dopaminergic neurons more selectively vulnerable
due to their extensive branching & the large amounts of energy needed to send nerve signals along this extensive network
what is the difference between normal and PD dopamine transmission
Normally, dopamine operates in a delicate balance with other neurotransmitters to help coordinate the millions of nerve and muscle cells involved in movement which results in controlled movement
in parkinsons disease. there are less dopamine cells in the substrata nigra which results in disturbed movement
