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Printable Handouts
Navigable Slide Index
- Introduction
- Section 5 - Ion excitability: Calcium
- Calcium – the beginning
- Biological importance of calcium ions
- Patch-clamp and fluorescent Ca2+ indicators
- Calcium as a universal signalling molecule
- Calcium signalling in neurones and glia: Extracellular vs. intracellular pathway
- Calcium signalling in neurones and neuroglia: General principles
- Spatio-temporal organisation
- ATP triggers calcium release from InsP3-sensitive stores in Bergmann glial cells in cerebellar slices
- Synchronised global calcium signals in cortex
- Propagating calcium waves in culture
- Mechanisms of Ca2+ wave propagation
- Section 6 - Ionic excitability: Sodium
- Sodium homeostasis and signalling
- How to monitor intracellular [Na+]
- Sodium as an astrocytic signalling molecule
- Recapitulation (3)
- Section 7 - Homeostatic transporters
- Membrane transporters
- Astroglial-specific glutamate transporters
- Astroglial Sxc- cystine/glutamate antiporter
- Regulation of synaptic and extrasynaptic glutamate levels
- Astroglial Na+-dependent vitamin C transporter SVCT2/SLC23A2
- Operation arrangements of NHE and NBC
- Recapitulation (4)
- Section 8 - Astrocytes as secretory cells of the CNS
- Secretory granules in glial cells of the grey matter
- Astrocytes as endocranial secretory cells
- Multiple mechanisms of astroglial secretion
- Astroglial secretory organelles
- Slowness of astroglial secretion
- Recapitulation (5)
- Section 9 - Astrocytes in synaptic transmission
- The ultrastructure of the CNS synapse
- Functional implication of microdomains
- The concept of the tripartite synapse
- The astrocytic synaptic cradle
- Homeostatic control of synapses
- Astroglial morphological plasticity
- Neurotransmitter transporters
- Glutamate homeostasis is mediated via glutamate-uptake and glutamate-glutamine shuttle
- Astrocytes supply glutamine, a precursor of glutamate and GABA to neurons
- Astrocytes control major neurotransmitters
- The epilogue
Topics Covered
- Intracellular ionic signalling associated with astroglial excitability
- Calcium and sodium ions
- Homeostatic membrane transporters
- Astrocytes as secretory cells of the CNS
- Astrocytes in synaptic transmission
- Functional implication of microdomains
- Tripartite synapse
- Astrocytic synaptic cradle
- astrocytes control homeostasis of the CNS
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Talk Citation
Verkhratsky, A. (2022, April 28). Astrocytes: definition, appearance and general physiology 2 [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 5, 2024, from https://doi.org/10.69645/XQJJ7693.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Alexei Verkhratsky has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
Astrocytes: definition, appearance and general physiology 2
Published on April 28, 2022
30 min
A selection of talks on Neurology
Transcript
Please wait while the transcript is being prepared...
0:03
Now, we are coming to mechanisms
of excitability of astrocytes.
By definition,
astrocytes are electrically
non-excitable cells.
This means that they cannot
produce a regenerative
action potential.
That, of course,
is a function of
neurons in the nervous system.
However, astrocytes do have
their own mechanism
of excitability,
which is represented
by changes in
the cytosolic
concentration of ions
and second messengers.
Of course, ion number one
which is a reversal second
messenger in many different cells,
tissues practically
all over the universe
or the living universe on Earth,
this is calcium.
0:49
Let me start with a small
historical digression.
Calcium had been discovered by
Professor Humphry Davy in 1808.
That is the reason
for the name is
because Humphry Davy
demonstrated that
lime is a combination
of metal and oxygen;
hence, calcium from the
Latin word 'calx' for chalk.
The biological importance of
1:14
calcium ions had been
found some years later.
That was Sydney Ringer,
who, in the 1880s,
performed several experiments in
different tissues and species
which demonstrated incredible
importance at this time.
One of his most
amazing experiments
was also extremely simple.
He took some fish from
the fish market in London
and put them in
normal tap water.
Normal tap water
was from the Thames
and, of course, it
had everything and
those animals survived
without any major problems.
But then he transferred
some of these fish into
distilled water, which
doesn't have calcium,
and these animals started
to die very slowly.
In order to rescue them,
the only thing that was
necessary to do was to add
a minor amount of calcium
into the distilled water.
That was the very
first experiment that
demonstrated the importance of
calcium as an ion
of life and death.