Behavioural Processes, Elsevier
ADAPTATION CONDITIONAL LARRY
12 (1986) 57-66
57
TO COLD SWIM STRESS-INDUCED TOLERANCE
HYPOTHERMIA:
ABSENCE
OF PAVLOVIAN
KOKKINIDIS’
1 Department of Psychology, S7N OWO (Canada)
(Accepted
29 April
University
of
Saskatchewan,
Saskatoon,
Saskatchewan,
1985)
ABSTRACT Adaptation to Cold Swim Stress-Induced Kokkinidis, L., 1986. Hypothermia: Absence of Pavlovian Conditional Tolerance. Behav. Processes 12: 57-66. Mice subjected to cold swim stress developed pronounced hypothermia. Exposure to warm water swim, however, had little or no effect on body temperature. After repeated exposure to cold swim, the stress-induced hypothermia was The finding that cold swim resulted in hypothermia, whereas warm attenuated. swim had no effect in this respect, provided a useful experimental design by which to assess the role of conditioning factors in the adaptation to the thermic effects of cold swim. In two subsequent experiments, mice received Adaptacold swim either in a familiar environment or in a novel environment. tion to the thermic effects of cold swim was observed when mice were tested in regardless of the environmental cues previously the distinctive environment, paired with repeated exposure to the cold swim stress. These findings suggest that contextual cues were not of primary importance in the development of tolerance to the thermic effects of cold swim stress. INTRODUCTION Tolerance effects
has
of
the
Presumably, adapt
to
processes
in
effects
with
the
repeated
repeated
is
(i.e.,
since
the
case
exposure effects to
0376-6357/86/$03.50
the
although
an
stimulus
to
observed
the
the
of
under-
associative
1979).
This
is
an
of to
of
the
the
drug The
drug.
systemic is
is
anticipatory to
the
the
reaction
the
drug
association
exposed
effects
effect
between the
eventually
direction
and
well
develops
organism
primary
not
surrounding
compensatory the
pairings,
Siegel,
and
to
physiological are
association
systemic in
ability
importance
array
opposite
conditioned
the
the
drug,
exposure.
organism’s
process
see
physiological
drug
Conditioning). the
when of
is
the
and
review
Pavlovian
absence
stimulus/drug
the
the
exposure be
the
that
and
chronic
emphasizing (for
and
behavioral
adaptation
thought
typically
(Siegel,
deliterious resistant
in
response
attenuated
drug
can
procedure
and
the
the after
reflects
assault,
is
repeated
response
drug,
As
the
procedure
conditioned
tolerance
evidence
it
to
agents
development
of
with
conditioned
develop
governing
speaking,
strengthened
of
of
accumulating
tolerance
administration
to
pharmacological
pharmacological
is
Generally
injection
observed
mechanisms
there
systemic
of
development
repeated
neurochemical stood,
been
a number
effects
strengthened drug
is
1979). with to
long-term
various of
anorexic
exposure
stressors
stress
to
effects
0 1986 Elsevier
the of Science
to
results
a variety in
an
organism.
For
restraint
stress
Publishers
of
drug
attenuation example, after
B.V. (Biomedical
treatments, of
rats
the
became
repeated
Division)
exposure
58
to
the
stressor
showed producing cold
effects
of
increased
(Zigmond
and
animals shock
chronic
McCarty, The
question
control
(cf.,
available chronic
The
stimulus
stress.
exposure
to
In
cold
environmental contextual
to
cues of
chronic
At
this
role
of
of
may be
stress
associated
the
1, were
design with
time,
study
thermic
evaluated, was
the
in
et
is
swim
in
neurochemical
was
in
in
the
procedure
Platt,
adaptation the
of
repeated
Experiments to
Stone
stimulus
evaluate
of
and
information
development
order
1981;
physiological,
little
to
including
al.,
under
factors
the
or observed
(Stone
come
effects and
employed cold
several
behavioral,
conditioning
footshock
adaptation,
can
there
involved
the
are
Anisman
the
stress
present
to
rats
ulcer
ordinarily
subsensitivity
whether
of
Experiment
see
stress,
and
exposure deficits
behavioral
reviews
chronic
1570),
There
receptor
factors
swim
the
(for
purpose
specificity
development
the
Chronic
1979).
however,
1978).
respect
stress. that
chronic
remains,
Anisman,
with
al.,
noradrenergic
after
Harvey,
behavioral
parallel
consequences
and
1582).
et
that
Similarly,
the
synthesis and
1583),
Platt, against
(Weiss
stress
neurochemical
bility
1982).
lethal
catecholamine
1982). and
Platt,
its
(Stone
inescapable
effects
and
to
swim protected
after
and
(Stone
a resistance
possi-
tolerance
to
daily 2 and
determine
are
to
important
3 an
whether in
the
tolerance.
EXPER I MENT 1
Methods Subjects Twenty-four naive male Swiss mice procurred from the Animal Resources Centre at the University of Saskatchewan served as subjects. Mice weighed 25-30 g at the beginning of the experiment, and were housed individually in standard polypropylene mouse cages with free access to food and water. Apparatus and Procedure Mice were randomly assigned to one of three groups: cold swim, warm swim or -Mice in the cold swim condition were placed in a no-swim (n = 8 per group). glass cylinder (18.5 cm in diameter and 25.0 cm high) filled to within 7.0 cm from the top with cold water (lO’C), and allowed to swim for 3 min. Body temperatures were taken prior to the swim session by inserting a lubricated small animal probe into the rectum (1.5 cm) for 30 set before a reading was taken on a Yellow Springs Instruments Tele-thermometer (model 43TD). Following the swim session mice were returned to their home cage, and 15 min later body Mice in the warm swim group were temperatures were recorded once again. treated in an identical manner as those in the cold swim condition, with the exception that water temperature was maintained at 3O’C. In the no-swim mice were placed into an empty polypropylene mouse cage for 3 min, condition, Body temperatures were taken immediately and then returned to their home cage. and 15 min after they were prior to animals being placed in the holding cage, Mice in the three conditions were tested daily returned to their home cage. for
15 consecutive
days.
59
Results
and
Figure the
Discussion 1 shows
lst,
8th
and
temperatures yielded
of
15th mice
their
of
respective
mice in
in the
the
the
the
pre-swim warm
warm
and
to
and
post-swim
either
X Day
multiple in
and
no swim
Group
mice
pre-
exposure in
Newman-Keuls
temperatures
mice
mean
a significant
p < .ot.
of
the
cold
group.
X Temperature
swim
no swim
(a
and Pre-
groups.
groups
were
warm
not
@S.E.M.)
swim,
of
and
variance
interaction, =
condition
temperatures,
no swim
or
Analysis
comparisons
cold
temperatures
.05) were
lower and
body of
revealed
the
post-swim
post-swim
significantly
these
F(4,42)
significantly
than
following
data
= 27.75, post-swim lower
than
temperatures
temperatures different
of from
one
another.
DAY 1
0 PRESWIM B POST SWIM
38
, DAY8
Fig. 1. Mean 8th, and 15th swim group.
and preexposure
post-swim temperatures to cold or warm swim,
(+ and
S.E.M.) following of control animals
the in
lst, the
no
60
Mice stress,
were but
still
to
temperatures pre-swim
a
of
hypothermic lesser
mice
in
temperatures,
after
eight
days
degree.
As shown
the
swim group
and
cold were
also
in
of
mice
in
the
warm
and
temperatures
of
mice
in
the
cold
swim group
days
initial
of
exposure
By the swim was were
warm
appeared groups
swim
stress.
As depicted
to
cold
swim
of
stress
mice
in
but
the
warm
no swim groups.
not
to
was
evident
were
and
The
to
the
days
observed
hyperthermia
after
test
not
session,
effects
of
cold
of
mice
that
different
lower This
post-swim
to
from
than
difference
in
these
was of
was
not
the
mice
in
groups
temperatures it
their
post-swim
temperatures
higher
although
after after
temperatures
were
their
post-swim higher
hypothermic
no swim groups.
than
post-swim
temperatures
significantly
a trend
body
However,
post-swim
of
since
than
post-swim
swim
lower
significantly
increase
fortuitous, every
were
1,
cold
post-swim
groups.
fifteen
they
significant
and
be
Figure for
although
no swim
tolerance
in
1,
to
significantly lower
respective
session,
exposure
in
these
significant
in
case.
If the
the
2 stimulus
thermic
repeatedly the
cold test
a small
EXPERIMENT
to
their
temperatures,
of
every
than
to
evident.
temperatures result
swim,
fifteenth
exposed
pre-swim
the
cold
were
significantly
temperatures
eight
of
Figure
aspects
effects
exposed
to
same environment,
mice
tested
cold
swim
in (c.f.,
cold
cold
the
environment
swim
swim
would
a stimulus Siegel,
of
of
show
in
stress, the
were then
context
behaviourally
situation
which
it of
important would
one
not
the
environment
augmented
was
in
tolerance
previously
adaptation
be expected
that
and
mice
tested
relative
associated
in to
with
1979).
Methods Subjects and Apparatus. Twenty-one naive male Swiss mice concerning subjects were the same as
served those
as subjects. described in
All other Experiment
particulars 1.
Animal Colony Environment. Mice were housed individually in polypropylene cages that were situated on aluminium racks in a 2.6 x 3.2 x 2.9 meter room with fluorescent lighting and a 12 hr light-dark cycle. Ambient room temperature was 21°C and sound levels Sound intensity measurements were made with a Bruel Kjaer sound were 60 dB. level meter (Model 2203; A scale). Distinctive Environment. The distinctive environment consisted of four identical aluminium chambers (70 cm long x 40 cm wide x 30 cm high) with an aluminium floor and top. A General Electric 60 watt light bulb and a 10 cm speaker were situated on the White noise was presented through the speaker and back wall of each chamber. was generated by a Grason-Stadler Noise Generator (Model 9018). Sound intensity levels in each chamber were 100 dB and ambient temperature in the chambers was maintained at 21’~.
61
Procedure Two groups of mice (n = 7 per group) received cold water swim (lO’C), and warm water swim (3O’C) for 24 days on an alternating schedule. One group received cold swim in the distinctive environment (DE), and on alternate days, warm swim in the colony environment (CE): Group ColdDistinctive Environment/Warm-Colony Environment (Cold-DE/Warm-CE) . The second group received cold swim in the colony environment, and on alternate days, warm swim in the distinctive environment: Group Cold-Colony Environment/Warm Distinctive Environment (Cold-GE/Warm-DE). Thus all animals were subjected to 12 days of cold and warm water swim and differed only in the environmental cues associated with the swim procedure. On days when the mice received a swim session in the colony environment, they were removed frm their home cage and placed in a glass cylinder containing either cold or warm water for 3 min, and then returned to their home cage (see Experiment 1 for details). On days when the mice were tested in the distinctive environment, their home cage was removed from the rack and placed in one of the aluminium chambers. Thirty min later the mice were removed from their cage and placed in a glass cylinder containing either cold or warm water The glass cylinder was situated in the aluminium chamber. for 3 min. Following the swim session mice were returned to their home cage, and remained in the distinctive environment for 1.5 min, at which time the cage was returned to the animal rack in the colony room. On the test day (Day 25), the mice in the Cold-DE/Warm-CE and Cold-CE/ Warm-DE groups were exposed to cold swim in the distinctive environment. Body temperatures were recorded imnediately prior to the cold swim session, and 15 min following exposure to cold swim, both on the first day of exposure to cold A third group of mice (n = 7) served as control subjects swim and on test day. and were exposed to each of the environments on alternate days for 24 days, but were not subjected to forced swim. Results
and
Pre-
Discussion
and
post-
Cold-GE/Warm-DE first of
session variance
of
F(2,18)
were
and
post-swim
as can groups.
and
That
is,
respective seen
degree
Figure
the
with
still
that
seen
mice
in
cold
upon
first
cold
on the
first
in
mice
in
the
on the
tolerance
was
comparable
the
distinctive day
to
and
session.
in
test
exposure
swim on test test
stress.
temperatures,
Cold-DE/Warm-CE
after
of
swim
observed
Experiment
swim
pre-swim
evident
Analysis
Cold-GE/Warm-DE
was
after
of
cold
no swim condition.
to
degree
and
the
2.
X Temperature
results
to
and
during
Figure
X Day the
respective
hypothermia
of
in
the
groups
temperatures 2,
Group
of
higher
Cold-DE/Warm-CE animals
exposure
their in
the
depicted
Cold-DE/Warm-CE
mice
temperatures
significantly
post-swim in
the
than of
relative
body
were
in
in
control
are
after
hypothermia
the
of
25)
Consistent
.Ol.
Cold-GE/Warm-DE
However,
groups
be
mice
(Day
evident
lower
substantially
stress.
p
ADAPTATION CONDITIONAL LARRY
12 (1986) 57-66
57
TO COLD SWIM STRESS-INDUCED TOLERANCE
HYPOTHERMIA:
ABSENCE
OF PAVLOVIAN
KOKKINIDIS’
1 Department of Psychology, S7N OWO (Canada)
(Accepted
29 April
University
of
Saskatchewan,
Saskatoon,
Saskatchewan,
1985)
ABSTRACT Adaptation to Cold Swim Stress-Induced Kokkinidis, L., 1986. Hypothermia: Absence of Pavlovian Conditional Tolerance. Behav. Processes 12: 57-66. Mice subjected to cold swim stress developed pronounced hypothermia. Exposure to warm water swim, however, had little or no effect on body temperature. After repeated exposure to cold swim, the stress-induced hypothermia was The finding that cold swim resulted in hypothermia, whereas warm attenuated. swim had no effect in this respect, provided a useful experimental design by which to assess the role of conditioning factors in the adaptation to the thermic effects of cold swim. In two subsequent experiments, mice received Adaptacold swim either in a familiar environment or in a novel environment. tion to the thermic effects of cold swim was observed when mice were tested in regardless of the environmental cues previously the distinctive environment, paired with repeated exposure to the cold swim stress. These findings suggest that contextual cues were not of primary importance in the development of tolerance to the thermic effects of cold swim stress. INTRODUCTION Tolerance effects
has
of
the
Presumably, adapt
to
processes
in
effects
with
the
repeated
repeated
is
(i.e.,
since
the
case
exposure effects to
0376-6357/86/$03.50
the
although
an
stimulus
to
observed
the
the
of
under-
associative
1979).
This
is
an
of to
of
the
the
drug The
drug.
systemic is
is
anticipatory to
the
the
reaction
the
drug
association
exposed
effects
effect
between the
eventually
direction
and
well
develops
organism
primary
not
surrounding
compensatory the
pairings,
Siegel,
and
to
physiological are
association
systemic in
ability
importance
array
opposite
conditioned
the
the
drug,
exposure.
organism’s
process
see
physiological
drug
Conditioning). the
when of
is
the
and
review
Pavlovian
absence
stimulus/drug
the
the
exposure be
the
that
and
chronic
emphasizing (for
and
behavioral
adaptation
thought
typically
(Siegel,
deliterious resistant
in
response
attenuated
drug
can
procedure
and
the
the after
reflects
assault,
is
repeated
response
drug,
As
the
procedure
conditioned
tolerance
evidence
it
to
agents
development
of
with
conditioned
develop
governing
speaking,
strengthened
of
of
accumulating
tolerance
administration
to
pharmacological
pharmacological
is
Generally
injection
observed
mechanisms
there
systemic
of
development
repeated
neurochemical stood,
been
a number
effects
strengthened drug
is
1979). with to
long-term
various of
anorexic
exposure
stressors
stress
to
effects
0 1986 Elsevier
the of Science
to
results
a variety in
an
organism.
For
restraint
stress
Publishers
of
drug
attenuation example, after
B.V. (Biomedical
treatments, of
rats
the
became
repeated
Division)
exposure
58
to
the
stressor
showed producing cold
effects
of
increased
(Zigmond
and
animals shock
chronic
McCarty, The
question
control
(cf.,
available chronic
The
stimulus
stress.
exposure
to
In
cold
environmental contextual
to
cues of
chronic
At
this
role
of
of
may be
stress
associated
the
1, were
design with
time,
study
thermic
evaluated, was
the
in
et
is
swim
in
neurochemical
was
in
in
the
procedure
Platt,
adaptation the
of
repeated
Experiments to
Stone
stimulus
evaluate
of
and
information
development
order
1981;
physiological,
little
to
including
al.,
under
factors
the
or observed
(Stone
come
effects and
employed cold
several
behavioral,
conditioning
footshock
adaptation,
can
there
involved
the
are
Anisman
the
stress
present
to
rats
ulcer
ordinarily
subsensitivity
whether
of
Experiment
see
stress,
and
exposure deficits
behavioral
reviews
chronic
1570),
There
receptor
factors
swim
the
(for
purpose
specificity
development
the
Chronic
1979).
however,
1978).
respect
stress. that
chronic
remains,
Anisman,
with
al.,
noradrenergic
after
Harvey,
behavioral
parallel
consequences
and
1582).
et
that
Similarly,
the
synthesis and
1583),
Platt, against
(Weiss
stress
neurochemical
bility
1982).
lethal
catecholamine
1982). and
Platt,
its
(Stone
inescapable
effects
and
to
swim protected
after
and
(Stone
a resistance
possi-
tolerance
to
daily 2 and
determine
are
to
important
3 an
whether in
the
tolerance.
EXPER I MENT 1
Methods Subjects Twenty-four naive male Swiss mice procurred from the Animal Resources Centre at the University of Saskatchewan served as subjects. Mice weighed 25-30 g at the beginning of the experiment, and were housed individually in standard polypropylene mouse cages with free access to food and water. Apparatus and Procedure Mice were randomly assigned to one of three groups: cold swim, warm swim or -Mice in the cold swim condition were placed in a no-swim (n = 8 per group). glass cylinder (18.5 cm in diameter and 25.0 cm high) filled to within 7.0 cm from the top with cold water (lO’C), and allowed to swim for 3 min. Body temperatures were taken prior to the swim session by inserting a lubricated small animal probe into the rectum (1.5 cm) for 30 set before a reading was taken on a Yellow Springs Instruments Tele-thermometer (model 43TD). Following the swim session mice were returned to their home cage, and 15 min later body Mice in the warm swim group were temperatures were recorded once again. treated in an identical manner as those in the cold swim condition, with the exception that water temperature was maintained at 3O’C. In the no-swim mice were placed into an empty polypropylene mouse cage for 3 min, condition, Body temperatures were taken immediately and then returned to their home cage. and 15 min after they were prior to animals being placed in the holding cage, Mice in the three conditions were tested daily returned to their home cage. for
15 consecutive
days.
59
Results
and
Figure the
Discussion 1 shows
lst,
8th
and
temperatures yielded
of
15th mice
their
of
respective
mice in
in the
the
the
the
pre-swim warm
warm
and
to
and
post-swim
either
X Day
multiple in
and
no swim
Group
mice
pre-
exposure in
Newman-Keuls
temperatures
mice
mean
a significant
p < .ot.
of
the
cold
group.
X Temperature
swim
no swim
(a
and Pre-
groups.
groups
were
warm
not
@S.E.M.)
swim,
of
and
variance
interaction, =
condition
temperatures,
no swim
or
Analysis
comparisons
cold
temperatures
.05) were
lower and
body of
revealed
the
post-swim
post-swim
significantly
these
F(4,42)
significantly
than
following
data
= 27.75, post-swim lower
than
temperatures
temperatures different
of from
one
another.
DAY 1
0 PRESWIM B POST SWIM
38
, DAY8
Fig. 1. Mean 8th, and 15th swim group.
and preexposure
post-swim temperatures to cold or warm swim,
(+ and
S.E.M.) following of control animals
the in
lst, the
no
60
Mice stress,
were but
still
to
temperatures pre-swim
a
of
hypothermic lesser
mice
in
temperatures,
after
eight
days
degree.
As shown
the
swim group
and
cold were
also
in
of
mice
in
the
warm
and
temperatures
of
mice
in
the
cold
swim group
days
initial
of
exposure
By the swim was were
warm
appeared groups
swim
stress.
As depicted
to
cold
swim
of
stress
mice
in
but
the
warm
no swim groups.
not
to
was
evident
were
and
The
to
the
days
observed
hyperthermia
after
test
not
session,
effects
of
cold
of
mice
that
different
lower This
post-swim
to
from
than
difference
in
these
was of
was
not
the
mice
in
groups
temperatures it
their
post-swim
temperatures
higher
although
after after
temperatures
were
their
post-swim higher
hypothermic
no swim groups.
than
post-swim
temperatures
significantly
a trend
body
However,
post-swim
of
since
than
post-swim
swim
lower
significantly
increase
fortuitous, every
were
1,
cold
post-swim
groups.
fifteen
they
significant
and
be
Figure for
although
no swim
tolerance
in
1,
to
significantly lower
respective
session,
exposure
in
these
significant
in
case.
If the
the
2 stimulus
thermic
repeatedly the
cold test
a small
EXPERIMENT
to
their
temperatures,
of
every
than
to
evident.
temperatures result
swim,
fifteenth
exposed
pre-swim
the
cold
were
significantly
temperatures
eight
of
Figure
aspects
effects
exposed
to
same environment,
mice
tested
cold
swim
in (c.f.,
cold
cold
the
environment
swim
swim
would
a stimulus Siegel,
of
of
show
in
stress, the
were then
context
behaviourally
situation
which
it of
important would
one
not
the
environment
augmented
was
in
tolerance
previously
adaptation
be expected
that
and
mice
tested
relative
associated
in to
with
1979).
Methods Subjects and Apparatus. Twenty-one naive male Swiss mice concerning subjects were the same as
served those
as subjects. described in
All other Experiment
particulars 1.
Animal Colony Environment. Mice were housed individually in polypropylene cages that were situated on aluminium racks in a 2.6 x 3.2 x 2.9 meter room with fluorescent lighting and a 12 hr light-dark cycle. Ambient room temperature was 21°C and sound levels Sound intensity measurements were made with a Bruel Kjaer sound were 60 dB. level meter (Model 2203; A scale). Distinctive Environment. The distinctive environment consisted of four identical aluminium chambers (70 cm long x 40 cm wide x 30 cm high) with an aluminium floor and top. A General Electric 60 watt light bulb and a 10 cm speaker were situated on the White noise was presented through the speaker and back wall of each chamber. was generated by a Grason-Stadler Noise Generator (Model 9018). Sound intensity levels in each chamber were 100 dB and ambient temperature in the chambers was maintained at 21’~.
61
Procedure Two groups of mice (n = 7 per group) received cold water swim (lO’C), and warm water swim (3O’C) for 24 days on an alternating schedule. One group received cold swim in the distinctive environment (DE), and on alternate days, warm swim in the colony environment (CE): Group ColdDistinctive Environment/Warm-Colony Environment (Cold-DE/Warm-CE) . The second group received cold swim in the colony environment, and on alternate days, warm swim in the distinctive environment: Group Cold-Colony Environment/Warm Distinctive Environment (Cold-GE/Warm-DE). Thus all animals were subjected to 12 days of cold and warm water swim and differed only in the environmental cues associated with the swim procedure. On days when the mice received a swim session in the colony environment, they were removed frm their home cage and placed in a glass cylinder containing either cold or warm water for 3 min, and then returned to their home cage (see Experiment 1 for details). On days when the mice were tested in the distinctive environment, their home cage was removed from the rack and placed in one of the aluminium chambers. Thirty min later the mice were removed from their cage and placed in a glass cylinder containing either cold or warm water The glass cylinder was situated in the aluminium chamber. for 3 min. Following the swim session mice were returned to their home cage, and remained in the distinctive environment for 1.5 min, at which time the cage was returned to the animal rack in the colony room. On the test day (Day 25), the mice in the Cold-DE/Warm-CE and Cold-CE/ Warm-DE groups were exposed to cold swim in the distinctive environment. Body temperatures were recorded imnediately prior to the cold swim session, and 15 min following exposure to cold swim, both on the first day of exposure to cold A third group of mice (n = 7) served as control subjects swim and on test day. and were exposed to each of the environments on alternate days for 24 days, but were not subjected to forced swim. Results
and
Pre-
Discussion
and
post-
Cold-GE/Warm-DE first of
session variance
of
F(2,18)
were
and
post-swim
as can groups.
and
That
is,
respective seen
degree
Figure
the
with
still
that
seen
mice
in
cold
upon
first
cold
on the
first
in
mice
in
the
on the
tolerance
was
comparable
the
distinctive day
to
and
session.
in
test
exposure
swim on test test
stress.
temperatures,
Cold-DE/Warm-CE
after
of
swim
observed
Experiment
swim
pre-swim
evident
Analysis
Cold-GE/Warm-DE
was
after
of
cold
no swim condition.
to
degree
and
the
2.
X Temperature
results
to
and
during
Figure
X Day the
respective
hypothermia
of
in
the
groups
temperatures 2,
Group
of
higher
Cold-DE/Warm-CE animals
exposure
their in
the
depicted
Cold-DE/Warm-CE
mice
temperatures
significantly
post-swim in
the
than of
relative
body
were
in
in
control
are
after
hypothermia
the
of
25)
Consistent
.Ol.
Cold-GE/Warm-DE
However,
groups
be
mice
(Day
evident
lower
substantially
stress.
p
