Lecture 5- Parkinsons

Question 1

4 major symptoms or Parkinson’s Disease (PD)

Answer 1

Tremor
Bradykinesia-slowness of movement
Hypokinesia-decreasing range of movement
Emotionally flat

Question 2

Substantia Nigra secretes?

Answer 2

The Pars compacta (black part) secretes dopamine using thin unmyelinated fibres into the Striatum

Question 3

6 steps in PD?

Answer 3

1. Nigroatriatal pathway uses thin unmyelinated fibres to keep the Striatum held in control
2. Glutamatergic fibre from the cerebral cortex causes info to be passed to Globus Pallidus and through Basal Ganglia (if normal)
3. In PD the Pars compacta cells are dead as very reactive to O2 species
4. Striatum doesn’t get enough dopamine input, meaning GABA neurons to VA-VL of thalamus go unchecked
5. too much GABA causes reduction in glutamate fibres from Thalamus to UMN
6. Hypo kinesics occurs due to reduction in cortex excitation

Question 4

Extremes of Dopamine levels

Answer 4

Too little- CATATONIA(stiffness and rigidity)

Too much- wild movement + psychotic behaviours (schizophrenia)

Question 5

Main drug treatment?

Answer 5

LEVO-DOPA (L-Dopa)
Is the precursor for dopamine and can pass blood brain barrier.
Can however cause DISKINESIA and has only 8 years of effectiveness.

Question 6

Lower parts of Striatum?

Answer 6

Lower cortex, lots of input from nigrostruatal pathway. MOOD + FEELING

Upper Part, NS pathway and more involved with MOTOR MOVEMENT

Question 7

Other treatment?

Answer 7

Surgical Lesions
1. Pallidotomy (Globus Pallidus internal)
2. Thalamotomy (VA-VL thalamus)
Both relieve inhibition caused by GABA

Deep Brain Stimulation

• Can increase growth of new cells
• allows a level of control especially good for some Dyskinesias