PTSD in women is associated with a block in conversion of progesterone to the GABAergic neurosteroids allopregnanolone and pregnanolone measured in plasma.

There is a need to identify new and more effective treatments for posttraumatic stress disorder (PTSD). Allopregnanolone and its stereoisomer pregnanolone (together termed ALLO) are metabolites of progesterone that positively and allosterically modulate GABA effects at GABAA receptors, thereby reducing anxiety and depression. Previous research revealed that women with PTSD had low cerebrospinal fluid (CSF) ALLO levels and a low ratio of ALLO to the allopregnanolone precursor 5α-DHP, consistent with deficient activity of the ALLO synthetic enzyme 3α-hydroxysteroid dehydrogenase (3α-HSD). The current study examined ALLO and the ratio of ALLO to 5α-DHP in plasma at rest and in response to psychophysiological stressors in trauma-exposed, medication-free women with and without PTSD. Participants were examined twice in random order during the early follicular phase (eFP) and mid-luteal phase (mLP) of the menstrual cycle. Plasma neurosteroids were measured using gas chromatography-mass spectrometry. Results indicate that the ALLO to 5α-DHP ratio in plasma increases between the eFP and mLP. In addition, women with PTSD have a lower ratio of ALLO to 5α-DHP than trauma-exposed healthy women, as well as blunted increases in this ratio in response to a moderately stressful laboratory procedure, i.e., differential fear conditioning, across the menstrual cycle. Clinically feasible testing for 3α-HSD dysfunction is critical to translating this line of research into clinical care. Measurement of this ratio in plasma could facilitate patient stratification in clinical treatment trials, as well as precision medicine targeting of treatments that address ALLO synthesis deficits in women with PTSD.

The role of PKC signaling in CRF-induced modulation of startle.

RATIONALE: Hypersignaling of corticotropin releasing factor (CRF) has been implicated in stress disorders; however, many of its downstream mechanisms of action remain unclear. In vitro, CRF1 receptor activation initiates multiple cell signaling cascades, including protein kinase A (PKA), protein kinase C (PKC), and mitogen-activated protein kinase kinase MEK1/2 signaling. It is unclear, however, which of these signaling cascades mediate CRF-induced behaviors during stress. OBJECTIVES: We examined the role of PKA, PKC, and MEK1/2 signaling pathways in CRF-induced anxiety as measured by startle hyperreactivity. METHODS: Mice treated with intracerbroventricular (ICV) ovine CRF (oCRF) were pretreated with the PKA inhibitor Rp-cAMPS, PKC inhibitor bisindolylmaleimide (BIM), or MEK1/2 inhibitor PD98059 (ICV) and assessed for acoustic startle reactivity. RESULTS: The PKC inhibitor BIM significantly attenuated CRF-induced increases in startle. BIM was also able to block startle increases induced by oCRF when both compounds were infused directly into the bed nucleus of stria terminalis (BNST). PKA and MEK1/2 inhibition had no significant effects on CRF-induced changes in startle at the dose ranges tested. CRF-induced disruption of prepulse inhibition was not significantly reversed by any of the three pretreatments at the dose ranges tested. CONCLUSIONS: PKC signaling is required for CRF-induced increases in startle, and this effect is mediated at least in part at the BNST. These findings suggest that PKC signaling cascades (1) may be important for the acute effects of CRF to induce startle hyperreactivity and (2) support further research of the role of PKC signaling in startle abnormalities relevant to disorders such as posttraumatic stress disorder.

A multivariate twin study of hippocampal volume, self-esteem and well-being in middle-aged men.

Self-esteem and well-being are important for successful aging, and some evidence suggests that self-esteem and well-being are associated with hippocampal volume, cognition and stress responsivity. Whereas most of this evidence is based on studies on older adults, we investigated self-esteem, well-being and hippocampal volume in 474 male middle-aged twins. Self-esteem was significantly positively correlated with hippocampal volume (0.09, P = 0.03 for left hippocampus, 0.10, P = 0.04 for right). Correlations for well-being were not significant (Ps > 0.05). There were strong phenotypic correlations between self-esteem and well-being (0.72, P < 0.001) and between left and right hippocampal volume (0.72, P < 0.001). In multivariate genetic analyses, a two-factor additive genetic and unique environmental (AE) model with well-being and self-esteem on one factor and left and right hippocampal volumes on the other factor fits the data better than Cholesky, independent pathway or common pathway models. The correlation between the two genetic factors was 0.12 (P = 0.03); the correlation between the environmental factors was 0.09 (P > 0.05). Our results indicate that largely different genetic and environmental factors underlie self-esteem and well-being on one hand and hippocampal volume on the other.

Testosterone modifies the effect of APOE genotype on hippocampal volume in middle-aged men.

BACKGROUND: The APOE epsilon4 allele is an established risk factor for Alzheimer disease (AD), yet findings are mixed for how early its effects are manifest. One reason for the mixed results could be the presence of interaction effects with other AD risk factors. Increasing evidence indicates that testosterone may play a significant role in the development of AD. The aim of the present study was to examine the potential interaction of testosterone and APOE genotype with respect to hippocampal volume in middle age. METHODS: Participants were men from the Vietnam Era Twin Study of Aging (n = 375). The mean age was 55.9 years (range 51-59). Between-group comparisons were performed utilizing a hierarchical linear mixed model that adjusted for the nonindependence of twin data. RESULTS: A significant interaction was observed between testosterone and APOE genotype (epsilon4-negative vs epsilon4-positive). Those with both low testosterone (> or =1 SD below the mean) and an epsilon4-positive status had the smallest hippocampal volumes, although comparisons with normal testosterone groups were not significant. However, individuals with low testosterone and epsilon4-negative status had significantly larger hippocampal volumes relative to all other groups. A main effect of APOE genotype on hippocampal volume was observed, but only when the APOE-by-testosterone interaction was present. CONCLUSIONS: These findings demonstrate an interaction effect between testosterone and the APOE epsilon4 allele on hippocampal volume in middle-aged men, and they may suggest 2 low testosterone subgroups. Furthermore, these results allude to potential gene-gene interactions between APOE and either androgen receptor polymorphisms or genes associated with testosterone production.

Circadian phase in adults of contrasting ages.

There is evidence that aging may impair phase-shifting responses to light synchronizers, which could lead to disturbed or malsynchronized circadian rhythms. To explore this hypothesis, 62 elder participants (age, 58 to 84 years) and 25 young adults (age, 19 to 40 years) were studied, first with baseline 1-wk wrist actigraphy at home and then by 72 h in-laboratory study using an ultra-short sleep-wake cycle. Subjects were awake for 60 minutes in 50 lux followed by 30 minutes of darkness for sleep. Saliva samples were collected for melatonin, and urine samples were collected for aMT6s (a urinary metabolite of melatonin) and free cortisol every 90 minutes. Oral temperatures were also measured every 90 minutes. The timing of the circadian rhythms was not significantly more variable among the elders. The times of lights-out and wake-up at home and urinary free cortisol occurred earlier among elders, but the acrophases (cosinor analysis-derived peak time) of the circadian rhythm of salivary melatonin, urinary aMT6s, and oral temperature were not significantly phase-advanced among elders. The estimated duration of melatonin secretion was 9.9 h among elders and 8.4 h among young adults (p < 0.025), though the estimated half-life of blood melatonin was shorter among elders (p < 0.025), and young adults had higher saliva melatonin and urinary aMT6s levels. In summary, there was no evidence for circadian desynchronization associated with aging, but there was evidence of some rearrangement of the internal phase-angles among the studied circadian rhythms.

Plasma cortisol and neuropeptide Y in female victims of intimate partner violence.

BACKGROUND: The experience of intimate partner violence (physical and sexual violence) has been linked to psychiatric disorders such as posttraumatic stress disorder, yet data on the neuroendocrine profile in this population is sparse. This study sought to examine baseline plasma cortisol and neuropeptide Y (NPY) levels in female victims of intimate partner violence (IPV). METHODS: Morning plasma samples were collected for cortisol and NPY determination in 22 women with histories of IPV (10 with current PTSD, 12 without current or lifetime PTSD) and 16 non-abused controls. RESULTS: Mean cortisol levels were significantly lower in IPV subjects compared with controls, but did not distinguish IPV subjects with and without PTSD. There were no significant differences in mean NPY levels between the groups. Neither cortisol nor NPY levels were significantly correlated with PTSD symptoms. CONCLUSIONS: These preliminary findings suggest that victims of IPV, like women traumatized by childhood abuse, may be characterized by alterations in hypothalamic-pituitary-adrenal axis functioning, however, further study is needed to identify specific stress system disturbances in this group.

Evidence that a single nucleotide polymorphism in the promoter of the G protein receptor kinase 3 gene is associated with bipolar disorder.

In a genome-wide linkage survey, we have previously shown evidence suggesting that the chromosome 22q12 region contains a susceptibility locus for bipolar disorder (BPD). Two independent family sets yielded lod scores suggestive of linkage at markers in this region near the gene G protein receptor kinase 3 (GRK3). GRK3 is an excellent candidate risk gene for BPD since GRK3 is expressed widely in the brain, and since GRKs play key roles in the homologous desensitization of G protein-coupled receptor signaling. We have also previously shown GRK3 expression to be induced by amphetamine in an animal model of mania using microarray-based expression profiling. To identify possible functional mutations in GRK3, we sequenced the putative promoter region, all 21 exons, and intronic sequence flanking each exon, in 14-22 individuals with BPD. We found six sequence variants in the 5'-UTR/promoter region, but no coding or obvious splice variants. Transmission disequilibrium analyses of one set of 153 families indicated that two of the 5'-UTR/promoter variants are associated with BPD in families of northern European Caucasian ancestry. A supportive trend towards association to one of these two variants (P-5) was then subsequently obtained in an independent sample of 237 families. In the combined sample, the P-5 variant had an estimated allele frequency of 3% in bipolar subjects, and displayed a transmission to non-transmission ratio of 26 : 7.7 (chi(2)=9.6, one-sided P value=0.0019). Altogether, these data support the hypothesis that a dysregulation in GRK3 expression alters signaling desensitization, and thereby predisposes to the development of BPD.

Decreased corticotropin-releasing factor receptor expression and adrenocorticotropic hormone responsiveness in anterior pituitary cells of Wistar-Kyoto rats.

The Wistar-Kyoto (WKY) rat shows signs of persistent activation of the hypothalamic-pituitary-adrenal axis, but the cause and site of this activation is not yet known. Chronically activated corticotrophs generally show blunted adrenocorticotropic hormone (ACTH) response to corticotropin releasing factor (CRF); therefore, the anterior pituitary responsiveness to ACTH secretagogues, CRF and vasopressin, was compared in male WKY and Wistar rats. Anterior pituitary CRF binding and CRF receptor mRNA expression was significantly decreased in WKY rats. ACTH response to CRF or vasopressin was markedly impaired, and vasopressin failed to potentiate the CRF-stimulated ACTH release in cultured WKY anterior pituitary cells. In contrast, CRF and vasopressin alone and in combination stimulated large, concentration-dependent increases in ACTH release in Wistar anterior pituitary cells. By contrast to the decreased ACTH secretory responses, steady-state anterior pituitary pro-opiomelanocortin mRNA levels were approximately 12-fold greater in WKY rats compared to Wistar rats, and they further increased in response to CRF stimulation. These findings suggest that, although the WKY rat corticotroph is under a chronic state of activation or disinhibition, the in vitro secretory responses to classic ACTH secretagogues are impaired.

Effects of acute progesterone administration in healthy postmenopausal women and normally-cycling women.

The goal of this study was to investigate the behavioral and subjective effects of single doses of progesterone (intramuscular) in post-menopausal women and in women with normal menstrual cycles. Although certain metabolites of progesterone (e.g., allopregnanolone) are known to bind to GABA(A) receptors and produce sedative-like effects in laboratory animals, few studies have examined the acute effects of these neurosteroids in humans. Postmenopausal women (N=10) received progesterone (25, 50, 100 mg im) or placebo at weekly intervals, and women with normal menstrual cycles (N=8) received progesterone (100 mg im) or placebo once a month during the early follicular phase. Dependent measures included plasma levels of progesterone and allopregnanolone, self-report measures of mood and subjective effects and psychomotor performance. Plasma concentrations of progesterone and allopregnanolone increased in a time and dose-dependent manner, with relatively little variability. The concentrations were similar in both groups, although the ratio of allopregnanolone to progesterone was higher in cycling women at certain time points. Contrary to expectations, progesterone produced only modest behavioral or subjective effects. In the cycling women, it produced mild sedative-like effects (i.e., decreases in ratings of Vigor and Friendliness). In the post-menopausal women, only the highest dose (100 mg) slightly increased ratings of feeling "sluggish". These results suggest that progesterone and its metabolites, at concentrations well beyond those attained during the normal menstrual cycle, produce only marginal sedative-like effects. These findings suggest that brief (i.e., several hours) increases in plasma levels of allopregnanolone do not have direct effects on mood.

Circulating human corticotropin-releasing factor-binding protein levels following cortisol infusions.

Corticotropin-releasing factor-binding protein (CRF-BP) is a 37 kDa protein present in the brain and plasma and is known to regulate the actions of CRF. It has been demonstrated that CRF-BP in the brain and the pituitary appears to be positively regulated by glucocorticoids. In this study, the effect of various doses of hydrocortisone infusions on plasma CRF-BP levels was assessed. Four groups of 10 age-matched males received a 100 min infusion of either placebo (saline), 40 microg/kg/h, 300 microg/kg/h or 600 microg/kg/h hydrocortisone. CRF-BP levels were measured via a LIRMA. In addition, levels of plasma ACTH and cortisol were measured by standard radioimmunoassay. As expected, plasma cortisol levels increased and plasma ACTH levels were suppressed following the infusion. When expressed as proportion of pre-infusion baseine, no significant changes in plasma CRF-BP levels were observed following the infusion for all hydrocortisone groups relative to the control group. However, a significant time-averaged positive correlation was found between CRF-BP and cortisol levels at low to moderate, but not high, cortisol levels. The data obtained in this study indicate that CRF binding protein levels within the time course examined may slightly appear to be affected in the peripheral circulation in response to pronounced, sustained hypercortisolemia.

Stress hormone dysregulation at rest and after serotonergic stimulation among alcohol-dependent men with extended abstinence and controls.

BACKGROUND: Alcohol dependence has been associated with long-lasting alterations in limbic-hypothalamic-pituitary-adrenal (LHPA) axis and serotonin (5-hydroxytryptamine [5-HT]) function. Other conditions that are associated with alcoholism (cigarette smoking and antisocial personality disorder [ASPD]) have been linked with disturbances in these interrelated systems. We evaluated the stress hormone response to 5-HTergic stimulation in alcohol-dependent men with extended abstinence (average abstinence duration, 4.3 months) and controls to determine the relative contributions of alcoholism, cigarette smoking, and ASPD on baseline and provoked plasma cortisol and adrenocorticotropin hormone (ACTH) concentrations. METHODS: One hundred nine alcohol-abstinent men with alcohol dependence (62%), habitual smoking (70%), and ASPD (43%) received D,L-fenfluramine (100 mg po) in a randomized, double-blind, placebo-controlled, crossover trial. The group of recovering alcohol-dependent individuals included abstinent primary alcohol-dependent men and alcohol-dependent men with ASPD, whereas the group of non-alcohol-dependent men comprised healthy controls and non-alcohol-dependent men with ASPD. Plasma cortisol and ACTH levels were obtained at AM baseline and at half-hour intervals after drug administration. Subjective ratings of drug response and physiological measures were also obtained at baseline and every 30 min. RESULTS: Abstinent alcohol-dependent men had significantly lower (approximately 20%) AM baseline plasma cortisol concentrations than non-alcohol-dependent men on both challenge days; however, no differences between the groups were observed with regard to resting AM plasma ACTH levels. After adjusting for these baseline differences, recovering alcohol-dependent men (area under curve = 35.6 +/- 37.4 [microg/dl] x min) had a twofold greater cortisol response to fenfluramine than non-alcohol-dependent men (area under curve = 17.5 +/- 32.5 [microg/dl] x min) (F = 5.1; df = 1,105; p < 0.03). The elevated cortisol response, which occurred primarily along the descending limb of the response curve, was paralleled by a nonsignificant statistical trend for alcohol-dependent men to also exhibit a greater ACTH response to fenfluramine at the 210-min (p < 0.07) and 240-min (P < 0.09) time points as compared with non-alcohol-dependent men. Cigarette smoking and ASPD did not affect hormonal responses, nor could the groups' subjective ratings and physiological measures be distinguished. CONCLUSIONS: Alcohol-dependent men with extended abstinence differed from age- and race-matched non-alcohol-dependent men in resting AM and fenfluramine-induced plasma cortisol levels. This dysfunction in glucocorticoid homeostatic mechanisms was associated with alcoholism and not with smoking or ASPD. We also observed a nonsignificant statistical trend for plasma ACTH levels to be elevated among alcohol-dependent men along the descending limb of the response curve. Alcohol-dependent men seemed to have inherited or acquired damage to 5-HT-regulated LHPA axis function, the precise mechanisms and sites of which remain to be determined.

Molecular biology of the CRH receptors-- in the mood.

Dysfunctioning of corticotropin-releasing hormone (CRH) and its receptors (CRH(1) and CRH(2)) has been linked to the development of stress-related disorders, such as mood and eating disorders. The molecular characterization of CRH(1) and CRH(2) receptors and their splice variants has generated detailed information on their pharmacology, tissue distribution and physiology. While mammalian CRH(1) receptors nonselectively bind CRH analogs, the ligand specificity of CRH(2) is narrower. CRH(1) receptors are predominantly expressed in the brain and pituitary, whereas CRH(2) receptor expression is limited to particular brain areas and to some peripheral organs. Molecular approaches to block CRH(1) receptor expression in the brain argue in favor of its involvement in the regulation of some aspects of the stress response. The CRH(2alpha) receptor may be more important for motivational types of behavior essential for survival, such as feeding and defense.(1)

GRK3 mediates desensitization of CRF1 receptors: a potential mechanism regulating stress adaptation.

Potential G protein-coupled receptor kinase (GRK) and protein kinase A (PKA) mediation of homologous desensitization of corticotropin-releasing factor type 1 (CRF1) receptors was investigated in human retinoblastoma Y-79 cells. Inhibition of PKA activity by PKI(5-22) or H-89 failed to attenuate homologous desensitization of CRF1 receptors, and direct activation of PKA by forskolin or dibutyryl cAMP failed to desensitize CRF-induced cAMP accumulation. However, treatment of permeabilized Y-79 cells with heparin, a nonselective GRK inhibitor, reduced homologous desensitization of CRF1 receptors by approximately 35%. Furthermore, Y-79 cell uptake of a GRK3 antisense oligonucleotide (ODN), but not of a random or mismatched ODN, reduced GRK3 mRNA expression by approximately 50% without altering GRK2 mRNA expression and inhibited homologous desensitization of CRF1 receptors by approximately 55%. Finally, Y-79 cells transfected with a GRK3 antisense cDNA construct exhibited an approximately 50% reduction in GRK3 protein expression and an ~65% reduction in homologous desensitization of CRF1 receptors. We conclude that GRK3 contributes importantly to the homologous desensitization of CRF1 receptors in Y-79 cells, a brain-derived cell line.

G-protein-coupled receptor kinase 3- and protein kinase C-mediated desensitization of the PACAP receptor type 1 in human Y-79 retinoblastoma cells.

Pituitary adenylyl cyclase-activating polypeptide (PACAP) receptor type 1 (PAC(1)) signaling and desensitization were investigated in human retinoblastoma Y-79 cells. Concentration-dependent stimulation of cAMP accumulation was observed in Y-79 cells incubated for 30 min with PACAP38, PACAP27, or VIP (10(-12) to 10(-6) M). The following EC(50) values were calculated: PACAP38, 24+/-3 pM; PACAP27, 99+/-8 pM; and VIP, 29+/-3 nM. Homologous desensitization of PAC(1) receptors in Y-79 cells pretreated with 10 nM PACAP38 or PACAP27 for 60 min was characterized by a 30-50% reduction in PACAP-stimulated cAMP accumulation (p<0.0001) and a two- to fivefold rightward shift in EC(50) values (p<0.0001). PAC(1) receptor desensitization was not accompanied by a reduction in PAC(1) mRNA expression. We concluded that the desensitizing effect of PACAP38 was homologous because neither corticotropin-releasing factor- nor (-)-isoproterenol-stimulated cAMP accumulation was altered by PACAP38 preincubation. Pretreating Y-79 cells with the protein kinase A (PKA) inhibitor H89 failed to inhibit homologous PAC(1) receptor desensitization. Similarly, pretreating Y-79 cells with the protein kinase C (PKC) inhibitors staurosporine or bisindolylmaleimide failed to alter homologous PAC(1) receptor desensitization. Although activation of PKA by dibutyryl cAMP or forskolin did not desensitize PAC(1) receptors, direct activation of PKC by PMA heterologously desensitized PAC(1) receptors, reducing cAMP accumulation 34.2+/-2.2% (p<0.001). Using RT-PCR, mRNA levels for G-protein-coupled receptor kinase 3 (GRK3), but not GRK2, were found to increase 2.2- to 4.8-fold in Y-79 cells exposed to PACAP38 for 10 min to 24 h (p<0.001). PAC(1) receptor desensitization decreased 72.5+/-4.3% (p<0.001) in Y-79 cells transfected with a GRK3 antisense cDNA construct that also reduced GRK3 protein expression 48.5+/-7.9% (p<0.0005). These experiments demonstrate that GRK3 plays an important role in the homologous desensitization of retinoblastoma PAC(1) receptors, whereas PKC, but not PKA, contributes to the heterologous desensitization of retinoblastoma PAC(1) receptors.

Interaction of neuropeptide Y and corticotropin-releasing factor signaling pathways in AR-5 amygdalar cells.

Corticotropin-releasing factor (CRF) is a 41 amino acid neuropeptide which is involved in the stress response. CRF and neuropeptide Y (NPY) produce reciprocal effects on anxiety in the central nucleus of the amygdala. The molecular mechanisms of possible CRF-NPY interactions in regulating anxiety behavior is not known. In the central nervous system, the action of NPY leads to inhibition of cAMP production while CRF is known to stimulate levels of cAMP in the brain. Consequently, we hypothesized that NPY may antagonize anxiety-like behavior by counter-regulating CRF-stimulated cAMP accumulation and activation of the protein kinase A pathway. We have engineered an immortalized amygdalar cell line (AR-5 cells) which express via RT-PCR, the CRF(2alpha), Y(1) and Y(5) NPY receptor. In addition, in these cells CRF treatment results in significant concentration-dependent increases in cAMP production. Furthermore, incubation of 3 microM CRF with increasing concentrations of NPY was able to significantly inhibit the increases in cAMP compared to that observed with 3 microM CRF treatment alone. These findings suggest that CRF and NPY may counter-regulate each other in amygdalar neurons via reciprocal effects on the protein kinase A pathway.

Identifying a series of candidate genes for mania and psychosis: a convergent functional genomics approach.

We have used methamphetamine treatment of rats as an animal model for psychotic mania. Specific brain regions were analyzed comprehensively for changes in gene expression using oligonucleotide GeneChip microarrays. The data was cross-matched against human genomic loci associated with either bipolar disorder or schizophrenia. Using this convergent approach, we have identified several novel candidate genes (e.g., signal transduction molecules, transcription factors, metabolic enzymes) that may be involved in the pathogenesis of mood disorders and psychosis. Furthermore, for one of these genes, G protein-coupled receptor kinase 3 (GRK3), we found by Western blot analysis evidence for decreased protein levels in a subset of patient lymphoblastoid cell lines that correlated with disease severity. Finally, the classification of these candidate genes into two prototypical categories, psychogenes and psychosis-suppressor genes, is described.

Cortisol circadian rhythms during the menstrual cycle and with sleep deprivation in premenstrual dysphoric disorder and normal control subjects.

BACKGROUND: In this study we extended previous work by examining whether disturbances in the circadian rhythms of cortisol during the menstrual cycle distinguish patients with premenstrual dysphoric disorder (PMDD) from normal control (NC) subjects. In addition, we tested the differential response to the effects of early and late partial sleep deprivation on cortisol rhythms. METHODS: In 15 PMDD and 15 NC subjects we measured cortisol levels every 30 min from 6:00 PM to 9:00 AM during midfollicular (MF) and late luteal (LL) menstrual cycle phases and also during a randomized crossover trial of early (sleep 3:00 AM-7:00 AM) versus late (sleep 9:00 PM-1:00 AM) partial sleep deprivation administered in two subsequent and separate luteal phases. RESULTS: In follicular versus luteal menstrual cycle phases we observed altered timing but not quantitative measures of cortisol secretion in PMDD subjects, compared with NC subjects: in the LL versus MF phase the cortisol acrophase was a mean of 1 hour earlier in NC subjects, but not in PMDD subjects. The effect of sleep deprivation on cortisol timing measures also differed for PMDD versus NC subjects: during late partial sleep deprivation (when subjects' sleep was earlier), the cortisol acrophase was almost 2 hours earlier in PMDD subjects. CONCLUSIONS: Timing rather than quantitative measures of cortisol secretion differentiated PMDD subjects from NC subjects both during the menstrual cycle and in response to early versus late sleep deprivation interventions.

Effects of sleep and sleep deprivation on interleukin-6, growth hormone, cortisol, and melatonin levels in humans.

The objective of this study was to evaluate the effects of nocturnal sleep, partial night sleep deprivation, and sleep stages on circulating concentrations of interleukin-6 (IL-6) in relation to the secretory profiles of GH, cortisol, and melatonin. In 31 healthy male volunteers, blood samples were obtained every 30 min during 2 nights: uninterrupted, baseline sleep and partial sleep deprivation-early night (awake until 0300 h). Sleep was measured by electroencephalogram polysomnography. Sleep onset was associated with an increase in serum levels of IL-6 (P < 0.05) during baseline sleep. During PSD-E, the nocturnal increase in IL-6 was delayed until sleep at 0300 h. Sleep stage analyses indicated that the nocturnal increase in IL-6 occurred in association with stage 1-2 sleep and rapid eye movement sleep, but levels during slow wave sleep were not different from those while awake. The profile of GH across the 2 nights was similar to that of IL-6, whereas the circadian-driven hormones cortisol and melatonin showed no concordance with sleep. Loss of sleep may serve to decrease nocturnal IL-6 levels, with effects on the integrity of immune system functioning. Alternatively, given the association between sleep stages and IL-6 levels, depressed or aged populations who show increased amounts of REM sleep and a relative loss of slow wave sleep may have elevated nocturnal concentrations of IL-6 with implications for inflammatory disease risk.

Plasma neuropeptide-Y concentrations in humans exposed to military survival training.

BACKGROUND: Neuropeptide-Y (NPY) is present in extensive neuronal systems of the brain and is present in high concentrations in cell bodies and terminals in the amygdala. Preclinical studies have shown that injections of NPY into the central nucleus of the amygdala function as a central anxiolytic and buffer against the effects of stress. The objective of this study was to assess plasma NPY immunoreactivity in healthy soldiers participating in high intensity military training at the U.S. Army survival school. The Army survival school provides a means of observing individuals under high levels of physical, environmental, and psychological stress, and consequently is considered a reasonable analogue to stress incurred as a result of war or other catastrophic experiences. METHODS: Plasma levels of NPY were assessed at baseline (prior to initiation of training), and 24 hours after the conclusion of survival training in 49 subjects, and at baseline and during the Prisoner of War (P.O.W.) experience (immediately after exposure to a military interrogation) in 21 additional subjects. RESULTS: Plasma NPY levels were significantly increased compared to baseline following interrogations and were significantly higher in Special Forces soldiers, compared to non-Special Forces soldiers. NPY elicited by interrogation stress was significantly correlated to the subjects' behavior during interrogations and tended to be negatively correlated to symptoms of reported dissociation. Twenty-four hours after the conclusion of survival training, NPY had returned to baseline in Special Forces soldiers, but remained significantly lower than baseline values in non-Special Forces soldiers. NPY was positively correlated with both cortisol and behavioral performance under stress. NPY was negatively related to psychological symptoms of dissociation. CONCLUSIONS: These results provide evidence that uncontrollable stress significantly increases plasma NPY in humans, and when extended, produces a significant depletion of plasma NPY. Stress-induced alterations of plasma NPY were significantly different in Special Forces soldiers compared to non-Special Forces soldiers. These data support the idea that NPY may be involved in the enhanced stress resilience seen in humans.

Low baseline and yohimbine-stimulated plasma neuropeptide Y (NPY) levels in combat-related PTSD.

BACKGROUND: Consistent with many studies demonstrating enhanced reactivity of the sympathetic nervous system in posttraumatic stress disorder (PTSD), the administration of yohimbine, a noradrenergic alpha(2)-antagonist, has been shown to increase core symptoms of PTSD and to induce greater increases in plasma 3-methyl-4-hydroxy-phenyl-glycol (MHPG) in subjects with PTSD compared with healthy control subjects. In turn, neuropeptide Y (NPY) has been shown to inhibit the release of norepinephrine from sympathetic noradrenergic neurons. METHODS: In the following study, plasma NPY responses to yohimbine and placebo were measured in a subgroup of 18 subjects with PTSD and 8 healthy control subjects who participated in the previous study of the effect of yohimbine on plasma MHPG. RESULTS: The PTSD subjects had lower baseline plasma NPY and blunted yohimbine-stimulated increases in plasma NPY compared with the healthy control subjects. Within the PTSD group, baseline plasma NPY levels correlated negatively with combat exposure scale scores, baseline PTSD and panic symptoms, and yohimbine-stimulated increases in MHPG and systolic blood pressure. CONCLUSIONS: This study suggests that combat stress-induced decreases in plasma NPY may mediate, in part, the noradrenergic system hyperreactivity observed in combat-related PTSD. The persistence of this decrease in plasma NPY may contribute to symptoms of hyperarousal and the expression of exaggerated alarm reactions, anxiety reactions, or both in combat veterans with PTSD long after war.