SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science XIII. Sleep and Gender
ship, University of Washington School of Nursing; Virginia Henderson
Research Grant and Psi Chaper-at-Large Research Grant, Sigma Theta
Tau Nursing International Honor Society
0914
SEX EFFECTS ON NREM SPECTRAL POWER WITH
GABAERGIC DRUGS
Hall-Porter JM 1 , Schweitzer PK 1 , Walsh JK 1,2
1
Sleep Medicine and Research Center, St. Luke’s Hospital,
Chesterfield, MO, USA, 2 Department of Psychology, Saint Louis
University, St. Louis, MO, USA
Introduction: Tiagabine, a selective GABA reuptake inhibitor, and
gaboxadol, a selective extrasynaptic GABA A
agonist, are two SWSenhancing
drugs that produce larger increases in NREM slow wave activity
(SWA; 0.75-4.5Hz) and theta (4.5-8Hz) power for females than
males. The current analysis explores the spectral profile of males and females
in response to sodium oxybate, a ligand of both GHB and GABA B
receptors.
Methods: Fifty-five healthy individuals (21M, 34F; age 27.04±9.05)
underwent a baseline PSG (2200-0700), followed by two days/nights of
sleep deprivation, each with a subsequent 3-hour nap (0800-1100) with
placebo (n=26) or 3.5mg sodium oxybate (n=29). Spectral analysis was
conducted on NREM epochs from the first three hours of baseline and
nap PSGs. Absolute power in quarter-Hz bins from central EEG was
summed into SWA, theta, alpha, sigma, and beta bands.
Results: Absolute SWA and theta power were increased after sleep
deprivation during the placebo naps, compared to baseline (p≤0.03);
no sex differences were found. Compared to placebo, sodium oxybate
increased relative-to-baseline SWA and theta (p≤0.001). Furthermore,
this increase in relative-to-baseline power was greater for females
(SWA=2.070; theta =2.484) than males (SWA=1.549; theta =1.934;
p≤0.022 for all). Increases above baseline in absolute SWA and theta,
respectively, were: 15.2% and 7.1% (female-placebo), 36.5% and 21.7%
(male-placebo), 107.0% and 148.4% (female-sodium-oxybate), 54.9%
and 93.4% (male-sodium-oxybate).
Conclusion: The greater SWA and theta power in females with sodium
oxybate is similar to that observed previously with the GABAergic
drugs tiagabine and gaboxadol. This contrasts with the 5-HT 2A
antagonist
eplivanserin, which was previously shown to enhance SWA without
sex differences. The receptors for gaboxadol (delta-containing GABA A
)
and sodium oxybate (GABA B
) are located extrasynaptically, and tiagabine-induced
increases in GABA likely spill out of the synapse to extrasynaptic
receptors. The sex difference observed may be associated with
interaction of neurosteroids with these extrasynaptic GABA inhibitory
processes.
Support (If Any): Jazz Pharmaceuticals
0915
SLEEP APNEA IN POSTMENOPAUSAL WOMEN:
ASSOCIATION WITH VISCERAL ADIPOSITY
Kritikou I 1 , Vgontzas AN 1 , Liao D 1 , Nazir R 1 , Fernandez-Mendoza J 1 ,
Chrousos G 2 , Bixler EO 1
1
Psychiatry, Penn State College of Medicine, Hershey, PA, USA, 2 First
Department of Pediatrics, University of Athens, Athens, Greece
Introduction: Visceral adiposity is associated with sleep apnea (OSAS)
in men, but very few studies have examined the association between
OSAS and visceral adiposity in women. It is known that both the prevalence
of OSAS and visceral adiposity increase in postmenopausal women.
Therefore, this study aimed to examine the association between sleep
apnea and visceral adiposity in postmenopausal women and to compare
the patterns of this association between postmenopausal women and
similar-aged men.
Methods: This study evaluated forty-two postmenopausal women, of
whom twenty-one had OSAS and twenty-one were normal controls. The
male sample consisted of twenty-two OSAS cases and twenty normal
controls. All subjects were monitored in the sleep laboratory for 4 consecutive
nights. The abdominal fat distribution wa measured with computed
tomography scans at five mid-lumbar levels (L1 - L5). Sex and
OSAS-status specific linear regression was used to assess the association
between AHI and visceral adipose tissue measures, adjusting for age,
BMI, and physical activity simultaneously.
Results: In both apneic women and apneic men, AHI was significantly
associated with the L1 - L5 overall visceral adipose tissue, with β=0.60
and 0.56 for women and men, respectively (both p < 0.05). Moreover,
there was a progressive decline of the magnitude of association from
L1 to L5 in women, with β=0.67, p=0.02 at L1 and β=0.19, p=0.51 at
L5, respectively. In contrast, in men this association remained relatively
constant across all five levels.
Conclusion: These preliminary data suggest a similar association between
the severity of sleep apnea and visceral adiposity in women and
in men. The progressive decline of the magnitude of such association
across lumbar levels seen in women, in contrast to the constant magnitude
across all lumbar levels in men, may suggest different metabolic
processes in visceral adiposity in postmenopausal apneic women versus
men.
0916
COMPENSATORY SLEEP EFFORT IS ASSOCIATED WITH
INSOMNIA SYMPTOMS IN WOMEN WITH AND WITHOUT
BREAST CANCER
Rissling M 1 , Natarajan L 3 , Cornejo M 2 , Ancoli-Israel S 1,2
1
SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San
Diego, CA, USA, 2 Department of Psychiatry, University of California
San Diego, San Diego, CA, USA, 3 Department of Family and
Preventive Medicine, University of California San Diego, San Diego,
CA, USA
Introduction: Chronic insomnia is prevalent in breast cancer patients
both during and following chemotherapy. Psychophysiological models
of insomnia suggest that compensatory sleep effort and pre-sleep cognitive
activity may be both a precipitating and perpetuating factor. However,
this has not been studied in cancer patients. This study examined
this question in a sample of recently-diagnosed breast cancer patients
and demographically-similar women without breast cancer.
Methods: 21 women (M age
=53.6 yrs, SE=2.9, range=38-81) diagnosed
with stage I-III breast cancer and 19 yoked, demographically-similar
healthy controls (M age
=53.6 yrs, SE=1.7, range=36-64) were studied
before (BL) and after 4 cycles of chemotherapy (C4). The Glasgow
Sleep Effort Scale (GSES), the Glasgow Content of Thoughts Inventory
(GCTI) and the Insomnia Severity Index (ISI) were evaluated. Data are
presented from both a linear and logistic regression analysis (α=0.05) on
C4 follow-up data only.
Results: There was no significant difference at C4 in mean GSES, GCTI
or ISI scores between cases and controls. A restricted linear regression
model explained a significant proportion of variance in ISI (R 2 =0.43,
F 3,31
=7.69, p=0.001), with GSES significantly predicting ISI (β=1.21,
t=2.64, p=0.01) in both groups. The addition of age and case-control
group and interaction terms between GSES, GCTI and group did not
significantly increase the variance explained in ISI (ΔR 2 =0.03). In an
exploratory logistic regression model, the continuous ISI variable was
dichotomized based on clinical cut-off for mild insomnia (ISI ≥8; Insomnia
n=15, No Insomnia n=22); in this model, GSES significantly
predicted insomnia status (β=1.20, p=0.01, OR=3.31).
Conclusion: Preliminary results suggest that independent of age or
breast cancer diagnosis, women with increased compensatory sleep
effort may experience more insomnia symptoms. Future analyses will
investigate this relationship longitudinally (pre- and post-treatment) in
a larger sample.
Support (If Any): CBCRP 15GB-0024, NCI CA112035 and the Moores
UCSD Cancer Center.
A313
SLEEP, Volume 34, Abstract Supplement, 2011