This study investigated the effects of acute prenatal ethanol exposure on social behavior and anxiety in Sprague-Dawley rats. Pregnant rats received injections of ethanol or saline on gestational day 12. Male offspring exposed to ethanol prenatally showed social deficits like decreased social investigation and contact behavior at various ages. Female offspring exposed to ethanol prenatally showed social deficits like decreased social investigation and play behavior at later adolescent and adult ages. Both male and female offspring exposed to ethanol prenatally showed increased social anxiety at some ages. When tested in non-social contexts in adulthood, there were no increases in anxiety-like behavior for either sex after prenatal ethanol exposure. Therefore, the social deficits and some anxiety effects of

1. ACUTE PRENATAL EXPOSURE TO ETHANOL ELICITS SOCIAL DEFICITS
AND ANXIETY-LIKE ALTERATIONS IN SPRAGUE-DAWLEY RATS
Elena I. Varlinskaya, Marvin R. Diaz, Jesse M. Cole
Developmental Exposure Alcohol Research Center (DEARC),
Department of Psychology, Binghamton University, Binghamton, NY 13902-6000.
• In humans, emerging evidence points to a relationship
between prenatal alcohol exposure, social deficits and
anxiety (Kelly et al., 2000; Kodituwakku, 2007; O’Connor et al.,
2002).
• Our previous research has shown that in Long Evans rats
even acute prenatal exposure to a high dose of ethanol on
gestational day (G)12 decreases social investigation,
contact behavior and play fighting in male offspring only
and produces social anxiety, indexed by social avoidance in
late adolescents and adults regardless of sex (Mooney &
Varlinskaya, 2011).
• In order to generalize the observed detrimental effects of
acute ethanol exposure on G12 and ensure that the effects
are not strain-specific, Sprague-Dawley rats were used in
the present study.
• Therefore, one of the aims of the present study was to
assess whether acute prenatal exposure to ethanol on G12
can produce sex-dependent and age-associated social
alterations in a strain-independent manner.
• Another objective of the study was to investigate whether
prenatal ethanol-induced anxiety-like alterations are
specific to social behavior or can be seen under non-social
test circumstances as well.
Introduction
Methods
• Subjects: male and female Sprague-Dawley rats exposed
to ethanol (EtOH) or saline on G12.
• Prenatal Exposure: pregnant females received two
intraperitoneal (i.p.) injections of EtOH or saline
– Ethanol exposure: 1st injection of 2.5 g/kg EtOH (20%,
v/v) was followed by the 2nd injection of 1.25 g/kg EtOH
in 2hr
– Saline exposure: two i.p. injections of equivalent
volumes of saline given 2 hr apart
• Social Interaction (SI) Test: P28 (early adolescence),
P42 (late adolescence), or P77 (young adulthood), familiar,
non-anxiogenic environment (2-compartment apparatus),
30 min pre-test social isolation in the test apparatus,
exposure to a non-manipulated social partner for 10 min
– Social investigation (sniffing of the partner)
– Contact Behavior (crawling under or over the partner,
social grooming)
– Play Fighting (pouncing or playful nape attack, following
and chasing, pinning)
– Social Preference/Avoidance [coefficient of
preference/avoidance = (crossovers to the partner –
crossovers away from the partner)/(total number of
crosses both to and away from the partner) x 100].
• Elevated Plus Maze (EPM): 5-min test on P80
following a 60-min period of social isolation in a novel
holding cage
– Measures of anxiety-like behavior: % open arm entries,
% open arm time
– Activity measures: number of closed arm entries
• Light/Dark Box (LDB): 5-min test on P87
– Latency to enter the dark chamber
– Latency to re-enter the light chamber (i.e., time to return
to the light side after initial entry to the dark side)
– Time spent in the light chamber
• Data Analyses:
– SI test: separate for each measure 2 (prenatal
exposure: Sal, EtOH) x 3 (age: P28, P42, P77) x 2 (sex)
analyses of variance (ANOVAs).
– EMP and L/D box: separate for each measure 2
(prenatal exposure: Sal, EtOH) x 2 (sex) ANOVAs.
Social Investigation Contact Behavior Play Behavior Social Preference/Avoidance
410.07
Significant decreases in social investigation were evident
in ethanol-exposed males relative to their saline-exposed
counterparts at all ages. Only older females exposed to
ethanol prenatally and tested at P42 and P77
demonstrated significant decreases in social investigation
relative to age-matched saline controls.
Ethanol-exposed males demonstrated significantly less
contact behavior than age-matched saline-exposed
controls at P28 and P77.In ethanol exposed females, this
social deficit was evident at P42 only.
Males demonstrated a gradual decrease in play
behavior regardless of prenatal exposure. In females,
play behavior also decreased with age and was
significantly lower in ethanol-exposed females than
saline-exposed controls at P42 and P77.
In males, prenatal ethanol-associated significant
decreases in the coefficient were evident in younger
animals tested at P28 and P42.Social preference was
significantly diminished by prenatal ethanol exposure in
older females tested at P42 and P77.
Summary and Conclusions
• In a manner similar to our previous findings with Long Evans rats (Mooney
& Varlinskaya, 2011), the present study using Sprague-Dawley rats clearly
demonstrates that ethanol exposure on G12 resulted in age- and sex-
dependent social deficits and anxiety-like alterations.
– Ethanol-exposed males showed substantial deficits in social
investigation at all ages, whereas social anxiety-like behavior (indexed
via decreases in social preference) declined with age and was no longer
evident in adult males.
– In contrast, ethanol-exposed early adolescent females showed no
changes in social behavior and social preference, whereas late
adolescent and adult females demonstrated social deficits and social
anxiety.
• In adulthood, when animals were tested under non-social circumstances,
anxiety-like behavior assessed on the elevated plus maze or in the
light/dark box was not enhanced in males and females following acute
prenatal exposure to ethanol.
– In contrast to SI testing, adult males and females surprisingly showed
decreased anxiety-like responses when tested in the EPM, but not in
the LDB.
– Therefore, acute exposure to ethanol on G12 has opposing effects on
different forms of anxiety in Sprague-Dawley rats.
• In summary, the findings of the present study suggest that, in general,
social alterations associated with acute exposure to ethanol on G12 are not
strain-specific, whereas prenatal ethanol-induced anxiety-like alterations
are rather specific to social interaction and are not evident under non-social
test circumstances.
Elevated Plus Maze Light/Dark Box
Percent open arm entries was higher in females than males.
Males prenatally exposed to ethanol showed more open arm
entries than saline controls. Similar sex differences were evident
for percent open arm time, with no effect of prenatal ethanol
exposure evident for this measure. Females were more active
than males, demonstrating more closed arm entries.
Behavior in the light/dark box was not affected by prenatal
ethanol exposure. Females showed significantly shorter
latencies for re-entering the light box than males.
Supported by NIH grant P50 AA017823
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