Astrocytic Calcium Signals Shape Network Activity and Behaviour - Krohn Flashcards
What are the functions of neurons in the brain?
Transfer and integration of information, sensory input, motor output, mainly electrical signals and memory.
What are the functions of astrocytes in the brain?
transfer and integration of information, calcium waves, and modulate neuronal activity.
What are some common astrocyte markers?
GFAP, EAAT1, S100beta
How do astrocytes develop?
Neural stem cells develop into neurons first, then they migrate along radial glia into layers, a developmental switch induces gliogenesis by activation of Notch and Sox9
How are astrocytes highly diverse and plastic?
diversity - astrocytes demonstrating diverse transcriptome, proteome or metabolome profiles or observable differences in proliferation, morphology, cell functions, cell signalling etc. when investigated.
heterogenity - types of astrocytes where diverse origin and function has been conclusively demonstrated.
plasticity - astrocytes responding to their local environment in a context/pathology-dependent way resulting in observable changes accross transcriptome, proteome, morphology, function, etc. Dynamic and plastic changes.
How do human astrocytes differ from mouse astrocytes?
They are larger than rodent astrocytes, thus have more contact points, have faster calcium dynamics, have a higher diversity of subtypes, can modulate human neuron activity.
What functions do astrocytes take up in the brain?
Astrocytes are the bridge to the outside world for the neurons. They connect with oligodendrocytes, regulate synaptic activity, connect with astrocytes, form the blood brain barrier, are involved in energy support and synaptogenesis.
How are calcium levels tightly regulated in astrocytes?
Ca2+ is an important information carrier in astrocytes, there are 3 major sources of Ca2+ - external, ER and mitochondrial. There are many different triggers for Ca2+ signals including neurotransmitters, mechanical stimulation, osmolarity, CO2 and neural activity. The most is in the extracellular calcium pahtway, the intracellular/mitochondrial dependent pathway, then in the intracellular/store-dependent pathway.
What is the basic internal calcium cascade?
Ligand activates GPCR, then Phospholipase C mediated PIP2 to IP3 conversion occurs, then IP3 triggers calcium efflux fro ER via IP3R
What are some pros and cons of using dyes to study astrocyte calcium?
Pros - high sensitivity, versatile - easy and quick to use, dual wavelength dyes allow for ratiometric measurements
Cons - concentration per cell viable and hard to estimate, not able to detect events in fine processes, non-specific loading, problematic in adult tissue.
What are pros and cons of using patching to study astrocyte calcium?
Pros - high sensitivity, targeted delivery to individual cells, controlled concentration (though often rather high), often in combination with electrophysiological measurements, some processes are filled.
Cons - highly invasive, time and labor intensive - no high throughput possible, not suitable for long-term studies
