Astrocytes are not only the “glue’ that
hold neurons together, providing nutrients for
their function, but they are also now seen as
important modulators of synaptic activity. They
have come to be seen as key partners in what
is called the “tripartite synapse” (i.e.
1. presynaptic terminals, 2. postsynaptic terminals,
and 3. the surrounding astrocytes). Increases
in astrocytic Ca releases glutamate and ATP onto
neurons, modulating and integrating neuronal
excitability.
Mapping of nicotinic acetylcholine receptor
(nAChR) subtypes and subunits in human brain
is far from complete, however it is clear that
multiple subunits are present (including alpha3,
alpha4, alpha5, alpha6 and alpha7, beta2, alpha3
and beta4) and that these receptors are not solely
distributed on neurons, but also on cerebral
vasculature and astrocytes. Changes in nAChR
expression in neuropsychiatric disorders appear
to be brain region and subtype specific and have
been shown in some instances to be associated
with pathology and symptomatology. The lab uses
2-photon microscopy (2PM) to study cortical astrocytic
calcium signaling in vivo in normal and
diseased states.
(Image of layer 1 and 2/3
cortical astrocytes in a living mouse
taken on our 2P microscope.)
