Lecture 13 Flashcards
Why is Parkinson’s disease caused?
Due to a loss of dopaminergic cells in the substantia nigra.
What kinds of environmental and genetic factors cause Parkinson’s?
Environmental-pesticide exposure, head injury, heavy metal exposure
Genes: LRRK2, PRKN, SNCA
What are the 2 ways you can treat (NOT CURE) Parkinsons?
Dopamine replacement treatment-L-Dopa
Deep Brain Stimulation
How does our body make dopamine?
The dietary amino acid Tyrosine is turned into L-Dopa with tyrosine hydroxalase (which we don’t have much of). Because of this, DOPA decarboxylase (which we have a lot of) converts L-Dopa into dopamine.
Why don’t we just inject dopamine? Why L-Dopa?
Dopamine doesn’t get past the blood-brain barrier, but L-Dopa can. By injecting L-Dopa directly, we bypass the tyrosine hydroxylase phase so we can get more dopamine out of L-Dopa.
Who discovered the L-Dopa cure and how did he do it?
Oliver Sacks-supervised people with influenza in the 20s who developed Parkinson’s symptoms-all went into comas. He then tried L-Dopa on a hunch and the patient woke up!
What did Oliver Sack’s experiment show?
A neurological condition can be treated by a drug that replaces neurotransmitters.
What are some of the side effects of too much dopamine?
Hypotension, arrhythmias, nausea, confusion, anxiety, vivid dreams, insomnia, auditory/visual hallucinations, psychosis.
What is deep brain stimulation?
Microelectrodes that are chronically implanted into the brain-stimulation of a specific area is provided via a pulse generator.
How does deep brain stimulation work for someone with Parkinson’s?
Bypasses the substantia nigra to target network responsible for movement-not a cure, but there are less side effects than L-Dopa.
What are some other ways to slow the symptoms of Parkinsons?
Activities with large movements (Boxing), singing (improves speech and swallowing).
What is neuroplasticity?
Modification at the synapse-how does our experience modify information flow at the level of the synapse.
Who was Donald Hebb?
First person to theorize about neuroplasticity-cells that fire together, wire together.
Who was Erik Kandel?
Awarded Nobel prize in physiology and medicine for his work on memory in Aplysia (sea slug)- great simple system to work on!
What are the 2 types of behaviour that Erik Kandel studied?
Habituation-Learning behaviour in which response to a stimuli weakens with repeated presentation
Sensitization- Response to a stimulus strengthens with repeated presentation- because the stimulus is novel, or stronger than normal.
How can we tell if an Aplysia has learned?
In response to a shock, it keeps itself contracted for a longer period of time.
What happens at the synapse with habituation?
Influx of calcium ions in response to an action potential decreases-less neurotransmitters are released at the presynaptic membrane, less depolarization of post synaptic membrane.
What happens at the synapse with sensitization?
Interneuron added which releases serotonin-reduces K+ efflux through potassium channels, prolonging an action potential. Prolonged action potential results in greater calcium influx, leading to increased neurotransmitter release and greater depolarization.
How does the neuron change in response to short-term learning versus long term?
Short-term- changes in neurotransmitter release
Long-term- actually changes connections between neurons.
