| dc.description | In nature, honey bees are exposed
to
both
aversive
and
appetitive
stimuli,
such
as
odors
and
colors
when
they
arrive
to
a
flower,
or
the
shape
of
a
spider
web
after
they
escape
from
it.
Bees
need
to
learn
from
these
experiences
in
order
to
appropriately
respond
to
its
environment.
With
a
relatively
simple
brain
with
only
960,000
neurons,
and
a
complex
learning
capacity,
comparable
to
that
of
vertebrate
organisms,
honey
bees
represent
a
great
model
to
study
the
molecular
mechanisms
of
learning
and
memory.
Many
of
the
molecular
components
of
learning
have
been
studied
in
honey
bees,
however
the
role
of
HCN
channels
and
Ih
currents
has
not
been
examined.
The
hyperpolarization-‐activated
cyclic
nucleotide
gated
channels
(HCN),
responsible
for
the
Ih
currents
production,
are
molecular
components
that
have
been
associated
with
learning
and
memory
in
vertebrates
(Nolan
et
al.,
2003).
The
present
work
examines
the
following
hypothesis:
If
HCN
channels
and
Ih
currents
play
a
role
in
honey
bee
learning
and
memory,
then
treatment
with
an
Ih
blocker
will
affect
both
their
aversive
and
appetitive
learning.
In
order
to
test
this
hypothesis
we
fed
honey
bees
two
Ih
blockers
ZD7288
and
DK-‐AH269
(Cilobradine)
and
followed
two
lines
of
inquiry:
Determine
Ih
blocker
effect
on
1)
honey
bee
aversive
learning
and
memory
by
using
the
electric
shock
avoidance
(ESA)
assay
2)
honey
bee
appetitive
learning
and
memory
by
using
the
proboscis
extension
response
conditioning
(PER)
assay.
By
using
the
ESA
assay,
we
found
that
feeding
honey
bees
the
Ih
blocker
ZD7288
does
not
have
a
significant
effect
on
the
aversive
learning
Acquisition
Phase.
Even
though
no significant
effect
of
treatment
with
ZD7288
on
ESA
was
found
on
the
aversive
learning
Acquisition
Phase,
a
tendency
was
observed,
in
which
individuals
treated
with
ZD7288
presented
a
higher
ESA
performance
than
individuals
from
the
control
group.
Following
this
tendency,
I
found
that
treatment
with
the
Ih
blocker
Cilobradine
(1.0,
2.0mM)
caused
a
statistically
significant
effect
on
the
learning
Acquisition
Phase,
enhancing
the
ESA
performance.
Treatment
with
ZD7288
caused
a
significantly
detrimental
effect
on
honey
bee
aversive
learning
Reinforcement
Phase,
while
on
the
contrary,
treatment
with
Cilobradine
(2.0mM)
caused
an
enhancing
effect
on
aversive
learning
Reinforcement
Phase.
On
the
other
hand,
for
aversive
STM,
ZD7288
has
a
significant
negative
effect
but
Cilobradine
has
no
effect.
I
examined
appetitive
learning
by
using
the
PER
assay
and
found
that
feeding
honey
bees
the
Ih
blocker
ZD7288
significantly
enhances
appetitive
learning
acquisition,
while
it
does
not
affect
appetitive
short
term
memory.
Taken
together
these
results
suggest
an
important
role
of
HCN
channels
and
Ih
currents
on
honey
bee
learning
modulation.
Given
that
HCN
channels
and
Ih
currents
have
been
associated
with
Dopamine
modulation
in
various
organisms,
I
suggest
that
the
observed
effects
of
treatment
with
the
Ih
blockers
ZD7288
and
Cilobradine
on
aversive
and
appetitive
learning
and
memory,
could
be
explained
by
changes
in
dopamine
levels.
Even
though
further
experiments,
such
as
pharmacological
experiments
using
dopamine
agonist
and
antagonists
are
needed
in
order
to
prove
this
inference. | |
