15-Neuronal_death - Neuronal Survival Cell Death Factors...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Neuronal Survival & Cell Death
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Factors Determine Neuron Survival 20-80% neurons died due to programmed cell death 5 factors affecting survival: 1. Target-derived signal 2. Synaptic input 3. Neighboring neurons 4. Surrounding glial cells 5. Blood vessel-derived signal
Image of page 2
Two neurons with condensed chromatin in their nuclei (arrows). Dying Neurons An electron micrograph shows a degenerating retinal ganglion cell with a clearly pyknotic nucleus (pn). TUNEL assay is used to detect apoptotic cells: T erminal transferase U TP N ick E nd L abeling Attach labeled nucleotides to the exposed 3’- hydroxyl ends of the DNA fragments
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Apoptosis and Necrosis shrinking Osmotic imbalance swelling Injury Natural Apoptosis: Graceful cell death Not to injure neighboring healthy neurons Necrosis: Abrupt death, bursting open membrane May release harmful enzymes or factors Phagocytized Pyknosis is the irreversible condensation of chromatin in the nucleus undergoing apoptosis
Image of page 4
DRG neuronal death occurs mostly in the DRG with less target muscle . Cell death occurs after projection axon contacted targets. Therefore, cell death important for selective elimination of neurons with less target. Cell Death in Chick D orsal R oot G anglia More cell death Limb muscle grows fast, and less cell death in the DRG innervating limb than those DRG innervating the axial musculature, showing target effect on the innervating sensory neurons’ survival.
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Motor Neuron Death Most rapid decrease of the number of healthy cells precisely coincides with the peak of apoptotic motor neurons! Study motor neurons innervating frog hind limb muscle
Image of page 6
Target Influences Neuronal Survival Remove limb bud, less motor neurons and DRG cells; Add limb bud, more motor neurons and DRG cells.
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern