Early electrical activity and calcium influx regulate crucial
aspects of neuronal development. Small-conductance calcium-
activated potassium (SK) channels regulate action
potential firing and shape calcium influx through feedback
regulation in mature neurons. These functions, observed in
the adult nervous system, make them ideal candidates to
regulate activity- and calcium-dependent processes in neurodevelopment.
However, to date little is known about the
onset of expression and regions expressing SK channel subunits
in the embryonic and postnatal development of the
central nervous system (CNS). To allow studies on the contribution
of SK channels to different phases of development
of single neurons and networks, we have performed a
detailed in situ hybridization mapping study, providing comprehensive
distribution profiles of all three SK subunits
(SK1, SK2, and SK3) in the rat CNS during embryonic and
postnatal development. SK channel transcripts are
expressed at early stages of prenatal CNS development.
The three SK channel subunits display different developmental
expression gradients in distinct CNS regions, with time
points of expression and up- or downregulation that can be
associated with a range of diverse developmental events.
Their early expression in embryonic development suggests
an involvement of SK channels in the regulation of developmental
processes. Additionally, this study shows how the
postnatal ontogenetic patterns lead to the adult expression
map for each SK channel subunit and how their coexpression
in the same regions or neurons varies throughout
development.
