Neurological Disorders Flashcards
What is one of the most defining features of Alzheimer’s disease?
Senile plaques
What are senile plaques?
Dense, roughly spherical, extracellular deposits that contain a protein called beta-amyloid.
Where in the brain are the senile plaques found?
Throughout the grey matter of the cerebral cortex and hippocampus. (can also appear in striatum, basal ganglia, and thalamus)
What are glial plaques usually surrounded by?
clumps of degenerating axons and glial cell activity, indicating that their presence is toxic to brain cells.
What accompanies senile plaques?
Neurofibrillary tangles (NFTs)
Where are neurofibrillary tangles found?
cytoplasm of neurons
What do neurofibrillary tangles resemble?
Tiny bundles of knotted string (technically called paired helical filaments)
What are neurofibrillary tangles made from?
A protein called tau
What does tau form an important part of?
The cell’s inner framework.
What enzyme was found to be reduced by up to 90 per cent in the cerebral cortex and hippocampus of Alzheimer’s brains?
Choline Acetyltransferase (CAT)
What is CAT involved in?
the synthesis of acetylcholine.
The only drugs which have shown benefits in the treatment of Alzheimer’s disease (and only in early stages) do what?
Increase levels of acetylcholine in the brain.
What are drugs that increase levels of acetylcholine in the brain?
Cholinesterase inhibitors such as Tacrine and Donepezil
How do cholinesterase inhibitors work?
these drugs work by inhibiting the enzyme acetylcholinesterase, which acts to break down acetylcholine after it has been released into the synapse. Inhibition of this enzyme leads to increased levels of acetylcholine in the synapse.
What is the amyloid cascade theory?
The theory proposes that the deposition of amyloid causes a chain reaction of events that leads to senile plaques, neurodegeneration and ultimately dementia.
