Glia—are they more than glue? The recent spotlight on glial cell function has revealed numerous ways in which these cells influence nervous system physiology, but how these roles manifest during CNS development remains unknown. Consider some of these questions: Is oligodendrocyte wrapping required for neuronal survival? Do astroglial cells regulate the targeting of synaptic partners? Do microglia help “sculpt” the brain during development?

Glia—are they more than glue? The recent spotlight on glial cell function has revealed numerous ways in which these cells influence nervous system physiology, but how these roles manifest during CNS development remains unknown. Consider some of these questions: Is oligodendrocyte wrapping required for neuronal survival? Do astroglial cells regulate the targeting of synaptic partners? Do microglia help “sculpt” the brain during development?

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

Problem 4TAHL: Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and...

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Fluorescent FM dyes partition reversibly into biological membranes without penetrating through them. Suppose that you have neurons cultured in a dish. You incubate the neurons with an FM dye, and then you wash them with medium to remove the dye. You find that if the neurons are stimulated to trigger action potentials during incubation with the dye, the synaptic regions of the neurons remain fluorescent after the wash. Can you explain why this effect may have occurred? Also, after generating fluorescent synaptic regions by this procedure, suppose that you trigger additional action potentials while continuing to wash with medium. Would you expect the synaptic regions to lose fluorescence?
Fluorescent FM dyes partition reversibly into biological membranes without penetrating through them. Suppose that you have neurons cultured in a dish, and you incubate them with an FM dye for a period of time before washing the cells with excess medium to remove the dye. a) You find that if you stimulate the neurons to trigger action potentials during incubation with the dye, the synaptic regions of the neurons remain fluorescent after the wash. Propose an explanation for this effect. b) After you have generated fluorescent synaptic regions by this procedure, suppose that you trigger further action potentials while continuing to wash with excess medium. Would you expect the synaptic regions to lose fluorescence? Explain.
A fellow classmate is planning to study endocytosis at neuronal synapses for their senior thesis. He is interested in what type of molecules neurons endocytose. They propose to use a cell line mutated in the microtubule motor kinesin to keep endocytic vesicles clustered at the synapse where they can be isolated into synaptosomes through differential centrifugation. Your classmate shows you protocols for growing neurons in culture and one that demonstrates the feasibility of isolating synaptosomes. But you know there is something else wrong with this proposal that will keep it from succeeding. What is it?
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If a postsynaptic cell has synapses from five different cells, and three cause EPSPs and two of them cause IPSPs, give an example of a series of depolarizations and hyperpolarizations that would result in the neuron reaching threshold.
Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and presynaptic excitatory neuron B terminates on the same postsynaptic cell on a dendrite located on the side of the cell body opposite the axon hillock. Explain why rapid firing of presynaptic neuron A could bring the postsynaptic neuron to threshold through temporal summation, thus initiating an action potential, whereas firing of presynaptic neuron B at the same frequency and the same magnitude of EPSPs may not bring the postsynaptic neuron to threshold.
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One of your classmates is planning to study endocytosis at neuronal synapses for their senior thesis. He is interested in what type of molecules neurons endocytose. They propose to use a cell line mutated in the microtubule motor kinesin to keep endocytic vesicles clustered at the synapse where they can be isolated into synaptosomes through differential centrifugation. The classmate shows you protocols for growing neurons in culture and one that demonstrates the feasibility of isolating synaptosomes. But you know there is something else wrong with this proposal that will keep it from succeeding. What is it?
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