BIOL 460 Exam 3 material

Notes condensed into flashcards. Starts at Alzheimer's in Memory from Central Nervous system, mostly Endocrine

Alzheimer’s Disease - Common or not?

Most common form of dementia

What are some characteristics of Alzheimers?

Loss of brain weight and volume with decreased cortical thickness with cognitive decline

Loss of neurons, dendritic spines and synapses

Accumulation of extracellular proteins called amyloid senile plaques

Accumulation of intracellular proteins forming neurofibriallary tangles

Amyloid precursor protein (APP) is broken down into peptides called what?

Amyloid beta (Aβ)

Aβ forms dimers and oligomers that join to form fibers in β pleated sheet structure that forms the

Amyloid senile plaques

Tau protein in normal state

Bind to microtubules and stabilizes them in axons

Tau proteins in alzheimer’s

They phosphorylate, aggregating in the cell body and dendrites and become insoluble, forming neurofibrillary tangles. Changes driven by Aβ

What is a major characteristic of soluble, intermediate tau proteins?

They’re more toxic

What are some toxic changes of Alzheimer’s?

Loss of synapses and dendritic spines

Reduced LTP

Excitotoxicity leading to neuron apoptosis

Mitochondrial release of reacitve oxygen species causing oxidative stress and apoptosis

Inflammation caused by these changes damage neurons

Astrocytes are a major source of what?

Apolipoprotein E (APOE)

What does apolipoprotein E do?

Carries lipids from degenerating neurons and other important activities for neuron health

What gene can increase the chance of developing Alzheimer’s?

APOE4

How does APOE4 affect people?

It promotes inflammatory damage to the blood-brain barrier

Drugs for Alzheimers

Acetylcholinesterase inhibitors

Antagonists of glutamate (hippocampus becomes more active as we age)

Drugs for depression

Antipsychotic drugs (if needed)

Lifestyle changes to build cognitive reserve, exercise, healthy eating, reducing risk factors

Short-term memory may involve a _______ where neurons synapse on each other in a circle

Recurrent circuit, or reverberating circuit

Long-term memory requires a ________ change in neuron chemical structure and synapses involving protein synthesis for consolidation of memory traces

relatively permanent

What is a good example for long-term memory in the hippocampus?

Long-term potentiation (LTP)

Synapses that are stimulated at a high frequency exhibit increased excitability. In these synapses, what is secreated by the presynaptic neuron?

Glutamate

What does the postsynaptic neuron have for glutamate?

AMPA and NMDA receptors

Which receptor does Glutamate bind to? What does it allow?

AMPA; allows Na+ to flow in

When Na+ flows it, it partially depolarizes the cell and activated NMDA receptor channels (which were inactive due to what?)

a Mg2+ blocking the pore

What does NMDA allow?

Ca2+ and Na+ to flow in

What does Ca2+ bind to? What does it do?

A protein called calmodulin, which activates an enzyme called CaMKII

What does CaMKII do?

causes more AMPA receptors to fuse into plasma membrane. Strengthens the synapse and becomes more sensitive to glutamate release (EPSP)

Rise is Ca2+ causes long term changes in postsynaptic neurons needed for?

Synaptic plasticity

Ca2+ enters nucleus and binds to calmodulin, activating what?

Protein kinase, which activates transcription factor

Protein kinase, which activates transcription factor called?

CREB (cyclic AMP response element binding protein)

What does CREB do?

Activates genes to produce mRNA and proteins, along with epigenetic changes of DNA

Stimulation of NMDA receptors and activation of CaMKII also results in what?

A growth of dendritic spines with AMPA receptors inserted on pyramidal cells

What do dendritic spines do?

Increase synaptic strength, stabilize during training and remain afterwards