Drugs - Dyskenesias - Huntingtons Flashcards
Which is an inherited disorder characterized by progressive dementia?
Huntington’s Chorea
Where do the two aspects of Huntington’s, chorea and dementia, arise from?
chorea - striatal pathology
dementia - cerebral pathology
What is seen on the terminal of the HD gene in Huntington’s?
40+ repeats of CAG (the codon for glutamine)
At what age is Huntington’s usually seen?
30s or 40s (4th and 5th decades of life)
What is Huntington’s believed to be related to?
An imbalance of dopamine, acetylcholine, and GABA
What leads to the involuntary movements in Huntington’s?
The destruction of cholinergic neurons and GABAergic neurons in the striatum (indirect pathway) = overactivity of dopamine
What is thought to be the cause of impaired cognitive functions and dementia in Huntington’s?
The concomitant loss of cerebral cortex neurons
What drugs are used to treat Huntington’s?
- Reserpine and tetrabenazine
- Antipsychotics
- alpha-methyl-p-tyrosine
What do reserpine and tetrabenazine do in the treatment of Huntington?
They deplete the dopamine stores in the CNS
What do antipsychotics do in the treatment of Huntington’s?
They block postsynaptic D2 receptors
What does alpha-methyl-p-tyrosine do in the treatment of Huntington’s?
It inhibits tyrosine hydroxylase so there is a decreased formation of dopamine
What is chorea exacerbated by?
Levodopa
What can low doses of dopamine agonist activate?
Presynaptic auto receptors which lead to inhibition of dopamine release
