Abstract:
Changes in the brain activity patterns are the neural correlates underlying
behavioural flexibility. Previous studies con
ducted in our
lab
oratory
have identified
CART
as a major anorexia inducing agent in zebrafish. CART induces neuronal
activity in the medial region of dorsal telencephalon (Dm) by
potentiating
the NMDA
receptor activit
y
rendering the Dm neurons hyperexcitab
le
.
Herein
, we used CART
as an entry point and identified the neural circuitries
that regulate
feeding drive in
zebrafish,
Danio rerio
.
We found that the CART and NPY neurons
, at discrete sites
in hypothalamus and in the ventral telencephalon are the major
gluco
-
responsive
neurons in the brain.
T
hese
apparently
ener
gy sensing neurons project to Dm
and
seem to
modulate the activity of the
constituent
neurons.
Both NPY and CART act
through parallel
, yet opposing,
mechanisms and alter the neuronal activity in
Dm
leading to a switch
-
like action between the
satiety and hunger
states
.
Each of these
state
s last
over an extended period of time and may be attributed to the biochemical
modulation of the neuronal activity.
Here, we describe the possible mechanisms
, and
their neuroanatomical correlates,
through which
these
neuromodulators influence
food intake
.
Sensory modalities like olfaction
also play a major role in sensing the
energy status
and influencing energy acquisition
. NPY
in the olfactory system
seems
to
mod
ulat
e
the
feeding drive
in
an
energy dependent manner
.
In brief,
Dm
emerges
as an integration centre of CART and NPY mediated interoceptive inputs, whose
activity
may determine
the feeding state.
