Neurons and Glia Flashcards
How does brain have to be processed in order to slice it and why?
- Fresh brain hard to cut therefore processed
- Brain has to be processed by preserving them in a paraformaldehyde which hardens the brain and can be sliced
What are the 2 ways the brain can be sliced in?
- Microtome
- Cryostat
What do you do in a microtome?
In this you embed the brain with wax in a particular orientation
What do you do in a cryostat?
- In this you freeze the brain in the orientation you want
- You can get really small slices about 2 mm in thickness
What do we need to do in order to see small structures?
In order to see small structures, we need to use staining methods
What does nissi stain do?
Stains RNA in purple dye
What does the golgi stain use and label?
Golgi stain uses silver chromate and labels cell body of some neurons
Why do we express fluorescent proteins and how do we view them?
We use fluorescent proteins which we express in cells . in order to see there anatomy and there physiology
-We use fluorescent microscopy where we share a particular frequency of light on the sample
What is clarity and what does this allow?
Clarity is where you get rid of the myelin fat making the brain more transparent
-This allows less light to scatter and therefore better images produced
What can green fluorescent protein be expressed in and due to what?
GFP can be expressed in biological organisms due to the universal genetic code
What are opsins?
Light emitting protein
What are the methods to target opsins to specific cells?
- Viral delivery
- Cre/lox technology
What are the steps involved in viral delivery?
- Carry out the sequencing of the GFP genetic code
- The GFP genetic code is packaged into a virus
- -Fluorescent protein DNA code is inserted into viral DNA along with a promoter. The promoter determines which cell type the virus can infect
- The virus infects neurons, inerting the GFP code into the DNA of the neuron
- DNA transcription and translation of GRP DNA to produce a fluorescent protein
What is Cre recombinase?
Cre recombinase is an enzyme that recognises loxp sites
What are genetic modifications dependent on in cre/lox technology?
Different genetic modification takes place dependent upon loxp location/orientation
What genetic modification occurs if 2 loxp sites are facing each other?
If 2 loxp sites are facing each other, inversion will occur of the gene
What genetic modification occurs if 2 loxp sites are facing the same way?
If 2 loxp sites are facing the same way, this results in deletion of gene between the 2 loxp sites
What genetic modification occurs if 2 loxp sites are on different strands of DNA?
If 2 loxp sites are on different strands of DNA, translocation of base sequence will occur
THE PROTOTYPICAL NEURON
The neuronal body
- Has a K+-rich cytosol
- Has the nucleus
- Performs DNA replication and transcription
- Has an endoplasmic reticulum
- RNA translation
- Golgi apparatus
- Protein folding
- Mitochondria
THE PROTOTYPICAL NEURON
The neuronal membrane
What proteins are present on the dendrites?
Dendritic proteins
-Ligand gated ion channels and G protein coupled receptors mostly expressed on dendrites
THE PROTOTYPICAL NEURON
The neuronal membrane
What proteins are present on the axon?
Axonal proteins
-Ion pumps and channels mostly expressed on axons
THE PROTOTYPICAL NEURON
The cytoskeleton
Microtubules
- Relatively large
- Tubulin composition
THE PROTOTYPICAL NEURON
The cytoskeleton
Microfilaments
- Actin composition
- Smallest fillament
THE PROTOTYPICAL NEURON
The cytoskeleton
Neurofilaments
- Called intermediate filaments in other cell types
- Composed of 5 proteins
- NFL
- NFM
- NFH
- Internexin
- Peripherin
