Relationship of Psychological Characteristics to Daily Life Ischemia: An Analysis From the National Heart, Lung, and Blood Institute Psychophysiological Investigations in Myocardial Ischemia.

OBJECTIVE: Cardiac ischemia during daily life is associated with an increased risk of adverse outcomes. Mental stress is known to provoke cardiac ischemia and is related to psychological variables. In this multicenter cohort study, we assessed whether psychological characteristics were associated with ischemia in daily life. METHODS: This study examined patients with clinically stable coronary artery disease (CAD) with documented cardiac ischemia during treadmill exercise (n = 196, mean [standard deviation] age = 62.64 [8.31] years; 13% women). Daily life ischemia (DLI) was assessed by 48-hour ambulatory electrocardiophic monitoring. Psychological characteristics were assessed using validated instruments to identify characteristics associated with ischemia occurring in daily life stress. RESULTS: High scores on anger and hostility were common in this sample of patients with CAD, and DLI was documented in 83 (42%) patients. However, the presence of DLI was associated with lower anger scores (odds ratio [OR] = 2.03; 95% confidence interval [CI] = 1.12-3.69), reduced anger expressiveness (OR = 2.04; 95% CI = 1.10-3.75), and increased ratio of anger control to total anger (OR = 2.33; 95% CI = 1.27-4.17). Increased risk of DLI was also associated with lower hostile attribution (OR = 2.22; 95% CI = 1.21-4.09), hostile affect (OR = 1.92; 95% CI = 1.03-3.58), and aggressive responding (OR = 2.26; 95% CI = 1.25-4.08). We observed weak inverse correlations between DLI episode frequency and anger expressiveness, total anger, and hostility scores. DLI was not associated with depression or anxiety measures. The combination of the constructs low anger expressiveness and low hostile attribution was independently associated with DLI (OR = = 2.59; 95% CI = 1.42-4.72). CONCLUSIONS: In clinically stable patients with CAD, the tendency to suppress angry and hostile feelings, particularly openly aggressive behavior, was associated with DLI. These findings warrant a study in larger cohorts, and intervention studies are needed to ascertain whether management strategies that modify these psychological characteristics improve outcomes.

Observation of Complement Protein Gene Expression Before and After Surgery in Opioid-Consuming and Opioid-Naive Patients.

Opioids may influence inflammation. We compared genes associated with pain and inflammation in patients who consumed opioids (3-120 mg of oral morphine equivalents per day) with those who did not for differential expression. White blood cells were assayed in 20 patients presenting for total lower extremity joint replacement. We focused on messenger ribonucleic acid expression of complement proteins. We report that the expression of a complement inhibitor, complement 4 binding protein A, was reduced, and the expression of a complement activator, complement factor D, was increased in opioid-consuming patients. We conclude that opioid consumption may influence expression of complement activators and inhibitors.

Gene Variants in Hepatic Metabolism, Gamma-Aminobutyric Acid-ergic Reward, and Prostaglandin Pathways in Opioid-Consuming and Opioid-Naïve Patients Presenting for Lower Extremity Total Joint Replacement.

Gene variants may contribute to individual differences in the experience of pain and the efficacy and reward of treatments. We explored gene variation in opioid-naïve and opioid-consuming patients undergoing elective lower extremity total joint replacement. We focused on 3 gene pathways including prostaglandin, gamma-aminobutyric acid (GABA)-ergic reward, and hepatic metabolism pathways. We report that for genes with possible or probable deleterious impact in these 3 pathways, opioid consumers had more gene variants than opioid-naïve patients (median 3 vs 1, P = .0092). We conclude that chronic opiate users may have genetic susceptibility to altered responses in reward/dependency and pain/inflammation pathways.

Early life trauma: An exploratory study of effects on OXTR and NR3C1 gene expression and nurturing self-efficacy in mothers of infants.

BACKGROUND: In animals, adverse early experience alters oxytocinergic and glucocorticoid activity and maternal behavior in adulthood. This preliminary study explored associations among childhood trauma (loss of a parent or sexual abuse in childhood), maternal self-efficacy, and leukocyte gene expression (mRNA) of oxytocin and glucocorticoid receptors (OXTR and NR3C1) in mothers of infants. METHODS: 62 mothers (20 with early life trauma) with healthy 3-month old infants reported maternal self-efficacy, depression, infant temperament, and overall social support; the effects of early trauma on these measures were assessed. Of these, 35 mothers (14 with early trauma) underwent blood draws after 2 infant feeding times; their OXTR and NR3C1 mRNA was compared to a control group of 25 no-infant women without early trauma, and also was examined for associations with self-efficacy. RESULTS: OXTR mRNA was increased in mothers of infants versus no-infant controls (p < 0.0003), and mothers with greatest prior maternal experience had higher OXTR than those with less experience (0-2 vs. 3+ older children, p < 0.033). Mothers with early trauma and less maternal experience had lower OXTR mRNA than no-trauma mothers (p < 0.029) and lower NR3C1 mRNA than controls (p < 0.004). Mothers with depression also had lower NR3C1 than other mothers (p < 0.003) but did not differ in OXTR. Mothers with early trauma also reported their support network to be less helpful and more upsetting and unpredictable than other mothers (p < 0.035-p < 0.005). Regarding maternal behavior, in mothers with early trauma, helpful support networks increased self-reported nurturing self-efficacy when babies were not fussy but decreased it with fussy babies (p < 0.05). Support was unrelated to self-efficacy in no-trauma mothers. Similarly, among mothers with low OXTR or NR3C1 (-1SD, most having early trauma and lower maternal experience), greater support was associated with lower self-efficacy (p < 0.05), while mothers with high OXTR or NR3C1 (+1SD) tended to have higher self-efficacy with greater support. CONCLUSIONS: These preliminary findings need confirmation in a larger sample but suggest that childhood trauma influences maternal behavior and both OXTR and NR3C1 pathways in mothers of infants, and that both depression and prior maternal experience may be other important factors. Effects on maternal behavior appear to require more complex modeling.

Propofol for Treatment-Resistant Depression: A Pilot Study.

Background: We hypothesized that propofol, a unique general anesthetic that engages N-methyl-D-aspartate and gamma-aminobutyric acid receptors, has antidepressant properties. This open-label trial was designed to collect preliminary data regarding the feasibility, tolerability, and efficacy of deep propofol anesthesia for treatment-resistant depression. Methods: Ten participants with moderate-to-severe medication-resistant depression (age 18-45 years and otherwise healthy) each received a series of 10 propofol infusions. Propofol was dosed to strongly suppress electroencephalographic activity for 15 minutes. The primary depression outcome was the 24-item Hamilton Depression Rating Scale. Self-rated depression scores were compared with a group of 20 patients who received electroconvulsive therapy. Results: Propofol treatments were well tolerated by all subjects. No serious adverse events occurred. Montreal Cognitive Assessment scores remained stable. Hamilton scores decreased by a mean of 20 points (range 0-45 points), corresponding to a mean 58% improvement from baseline (range 0-100%). Six of the 10 subjects met the criteria for response (>50% improvement). Self-rated depression improved similarly in the propofol group and electroconvulsive therapy group. Five of the 6 propofol responders remained well for at least 3 months. In posthoc analyses, electroencephalographic measures predicted clinical response to propofol. Conclusions: These findings demonstrate that high-dose propofol treatment is feasible and well tolerated by individuals with treatment-resistant depression who are otherwise healthy. Propofol may trigger rapid, durable antidepressant effects similar to electroconvulsive therapy but with fewer side effects. Controlled studies are warranted to further evaluate propofol's antidepressant efficacy and mechanisms of action. ClinicalTrials.gov: NCT02935647.

Correction: Antidepressant and Neurocognitive Effects of Isoflurane Anesthesia versus Electroconvulsive Therapy in Refractory Depression.

[This corrects the article DOI: 10.1371/journal.pone.0069809.].

Neural consequences of post-exertion malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Post exertion malaise is one of the most debilitating aspects of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, yet the neurobiological consequences are largely unexplored. The objective of the study was to determine the neural consequences of acute exercise using functional brain imaging. Fifteen female Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients and 15 healthy female controls completed 30min of submaximal exercise (70% of peak heart rate) on a cycle ergometer. Symptom assessments (e.g. fatigue, pain, mood) and brain imaging data were collected one week prior to and 24h following exercise. Functional brain images were obtained during performance of: 1) a fatiguing cognitive task - the Paced Auditory Serial Addition Task, 2) a non-fatiguing cognitive task - simple number recognition, and 3) a non-fatiguing motor task - finger tapping. Symptom and exercise data were analyzed using independent samples t-tests. Cognitive performance data were analyzed using mixed-model analysis of variance with repeated measures. Brain responses to fatiguing and non-fatiguing tasks were analyzed using linear mixed effects with cluster-wise (101-voxels) alpha of 0.05. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients reported large symptom changes compared to controls (effect size ≥0.8, p<0.05). Patients and controls had similar physiological responses to exercise (p>0.05). However, patients exercised at significantly lower Watts and reported greater exertion and leg muscle pain (p<0.05). For cognitive performance, a significant Group by Time interaction (p<0.05), demonstrated pre- to post-exercise improvements for controls and worsening for patients. Brain responses to finger tapping did not differ between groups at either time point. During number recognition, controls exhibited greater brain activity (p<0.05) in the posterior cingulate cortex, but only for the pre-exercise scan. For the Paced Serial Auditory Addition Task, there was a significant Group by Time interaction (p<0.05) with patients exhibiting increased brain activity from pre- to post-exercise compared to controls bilaterally for inferior and superior parietal and cingulate cortices. Changes in brain activity were significantly related to symptoms for patients (p<0.05). Acute exercise exacerbated symptoms, impaired cognitive performance and affected brain function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients. These converging results, linking symptom exacerbation with brain function, provide objective evidence of the detrimental neurophysiological effects of post-exertion malaise.

Fatigue sensation and gene expression in trained cyclists following a 40 km time trial in the heat.

PURPOSE: We examined the effect of race-effort cycling exercise with and without heat stress on post-exercise perceptions of fatigue and pain, as well as mRNA expression in genes related to exercise responses. METHODS: Trained cyclists (n = 20) completed 40 km time trials during temperate (TC, 21 °C) and hot (HC, 35 °C) conditions. Blood lactates were measured 1 and 5 min post-exercise. Venous blood samples and ratings of fatigue and pain perceptions were obtained at baseline and at 0.5, 8, 24, and 48 h post-exercise. Leukocyte mRNA expression was performed for metabolite detecting, adrenergic, monoamine, and immune receptors using qPCR. RESULTS: Significantly lower mean power (157 ± 32.3 vs 187 ± 40 W) and lactates (6.4 ± 1.7 vs 8.8 ± 3.2 and 4.2 ± 1.5 vs 6.6 ± 2.7 mmol L(-1) at 1- and 5-min post-exercise) were observed for HC versus TC, respectively (p < 0.05). Increases (p < 0.05) in physical fatigue and pain perception during TTs did not differ between TC and HC (p > 0.30). Both trials resulted in significant post-exercise decreases in metabolite detecting receptors ASIC3, P2X4, TRPV1, and TRPV4; increases in adrenergic receptors α2a, α2c, and ß1; decreases in adrenergic ß2, the immune receptor TLR4, and dopamine (DRD4); and increases in serotonin (HTR1D) and IL-10 (p < 0.05). Post-exercise IL-6 differed between TC and HC, with significantly greater increases observed following HC (p < 0.05). CONCLUSIONS: Both TT performances appeared to be regulated around a specific sensory perception of fatigue and pain. Heat stress may have compensated for lower lactate during HC, thereby matching changes in metabolite detecting and other mRNAs across conditions.

Gene Expression Factor Analysis to Differentiate Pathways Linked to Fibromyalgia, Chronic Fatigue Syndrome, and Depression in a Diverse Patient Sample.

OBJECTIVE: To determine if independent candidate genes can be grouped into meaningful biologic factors, and whether these factors are associated with the diagnosis of chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS), while controlling for comorbid depression, sex, and age. METHODS: We included leukocyte messenger RNA gene expression from a total of 261 individuals, including healthy controls (n = 61), patients with FMS only (n = 15), with CFS only (n = 33), with comorbid CFS and FMS (n = 79), and with medication-resistant (n = 42) or medication-responsive (n = 31) depression. We used exploratory factor analysis (EFA) on 34 candidate genes to determine factor scores and regression analysis to examine whether these factors were associated with specific diagnoses. RESULTS: EFA resulted in 4 independent factors with minimal overlap of genes between factors, explaining 51% of the variance. We labeled these factors by function as 1) purinergic and cellular modulators, 2) neuronal growth and immune function, 3) nociception and stress mediators, and 4) energy and mitochondrial function. Regression analysis predicting these biologic factors using FMS, CFS, depression severity, age, and sex revealed that greater expression in factors 1 and 3 was positively associated with CFS and negatively associated with depression severity (Quick Inventory for Depression Symptomatology score), but not associated with FMS. CONCLUSION: Expression of candidate genes can be grouped into meaningful clusters, and CFS and depression are associated with the same 2 clusters, but in opposite directions, when controlling for comorbid FMS. Given high comorbid disease and interrelationships between biomarkers, EFA may help determine patient subgroups in this population based on gene expression.

It's Complicated: Marital Ambivalence on Ambulatory Blood Pressure and Daily Interpersonal Functioning.

BACKGROUND: Marriage decreases cardiovascular morbidity although relationship quality matters. While some marriages contain highly positive aspects (supportive), marriages may also simultaneously contain both positive and negative aspects (ambivalent). Individuals whose spouses or own behavior is ambivalent may not experience the same cardiovascular-protective benefits of marriage. PURPOSE: The purpose of this study is to elucidate the physiological pathways by which marital quality may influence long-term health and examine ambivalent behavior on interpersonal-functioning and ambulatory blood pressure (ABP). METHODS: Interpersonal functioning and ABP were examined in 94 couples. RESULTS: Spousal and own ambivalent behavior was associated with lower intimacy (ps < .01) and higher systolic ABP (ps < .01). Spousal ambivalent behavior was associated with lower ratings of partner responsiveness (p < .01) and less self- and spousal-disclosure (ps < .05). Mediational analyses indicated that own behavior mediated links between spousal ambivalent behavior and ABP. CONCLUSIONS: Despite the positivity in relationships, individuals whose spouses' or own behavior is ambivalent may not receive cardiovascular protection from this positivity.

Effect of Pregabalin on Cardiovascular Responses to Exercise and Postexercise Pain and Fatigue in Fibromyalgia: A Randomized, Double-Blind, Crossover Pilot Study.

Pregabalin, an approved treatment for fibromyalgia (FM), has been shown to decrease sympathetic nervous system (SNS) activity and inhibit sympathetically maintained pain, but its effects on exercise responses have not been reported. Methods. Using a randomized double-blind crossover design, we assessed the effect of 5 weeks of pregabalin (versus placebo) on acute cardiovascular and subjective responses to moderate exercise in 19 FM patients. Blood pressure (BP), heart rate (HR), and ratings of perceived exertion (RPE) during exercise and ratings of pain, physical fatigue, and mental fatigue before, during, and for 48 hours after exercise were compared in patients on pregabalin versus placebo and also versus 18 healthy controls. Results. On placebo, exercise RPE and BP were significantly higher in FM patients than controls (p < 0.04). Pregabalin responders (n = 12, defined by patient satisfaction and symptom changes) had significantly lower exercise BP, HR, and RPE on pregabalin versus placebo (p < 0.03) and no longer differed from controls (p > 0.26). Cardiovascular responses of nonresponders (n = 7) were not altered by pregabalin. In responders, pregabalin improved ratings of fatigue and pain (p < 0.04), but negative effects on pain and fatigue were seen in nonresponders. Conclusions. These preliminary findings suggest that pregabalin may normalize cardiovascular and subjective responses to exercise in many FM patients.

A cross-sectional analysis of the association between perceived network social control and telomere length.

OBJECTIVE: Social control in the health domain refers to attempts by social network members to get an individual to modify their health behaviors. According to the dual effects model of social control, having one's health behavior controlled by others should be related to healthier behavioral change, but might arouse psychological distress as one may resent being controlled. Despite potential healthy behavior change, the stress of social control may thus be detrimental as interpersonal stress has been related to negative health outcomes. In the present study, the association between perceived social control and telomere length was tested to examine its association to biological outcomes. METHOD: In this cross-sectional study, a relatively healthy community sample of 140 middle age and older adults completed measures of perceived social control, perceived stress, and health behaviors. Peripheral blood mononuclear cells were used to determine telomere length. RESULTS: Main results showed that higher levels of perceived direct social network control were associated with shorter telomere length. These links were not influenced by statistical controls for medication use, self-rated health, trait hostility, and optimism. Perceived social control was also related to greater perceived stress but not health behaviors overall. However, neither perceived stress nor health behaviors mediated the link between social control and telomere length. CONCLUSIONS: Although the study design precludes strong inferences, these results suggest that perceived social control may be associated with cellular aging. These data also highlight the utility of integrating biological outcomes into social control models. (PsycINFO Database Record

Blood pressure, salivary cortisol, and inflammatory cytokine outcomes in senior female cancer survivors enrolled in a tai chi chih randomized controlled trial.

PURPOSE: Older cancer survivors are a vulnerable population due to an increased risk for chronic diseases (e.g., cardiovascular disease) compounded with treatment late-effects and declines in physical functioning. Therefore, interventions that reduce chronic disease risk factors (i.e., blood pressure, chronic inflammation, and cortisol) are important in this population. Tai chi chih (TCC) is a mind-body exercise associated with reductions in chronic disease risk factors, but has not been examined with older cancer survivors. In a feasibility randomized controlled trial of TCC, we examined secondary outcomes of blood pressure, salivary cortisol, and inflammatory cytokines (interleukin (IL)-6, IL-12, tumor necrosis factor-α, IL-10, IL-4) due to their implications in chronic diseases. METHODS: Sixty-three senior female cancer survivors (M age = 67 years, SD = 7.15) with physical functioning limitations (SF-12 physical functioning ≤80 or role-physical ≤72) were randomized to 12-weeks (60-min, three times a week) of TCC or Health Education control (HEC) classes. Resting blood pressure, 1-day salivary cortisol samples, and fasting plasma samples for cytokine multiplex assays were collected at baseline and 1-week post-intervention. RESULTS: Controlling for baseline values, the TCC group had significantly lower systolic blood pressure (SBP, p = 0.002) and cortisol area-under-curve (AUC, p = 0.02) at post-intervention than the HEC group. There was no intervention effect on inflammatory cytokines (p's > 0.05). CONCLUSIONS: This TCC feasibility trial was associated with significant reductions in SBP and cortisol AUC in senior female cancer survivors. Larger, definitive trials are needed to confirm these findings. IMPLICATIONS FOR CANCER SURVIVORS: Senior survivors' have an increased risk for chronic diseases; however, TCC interventions may help reduce associated risk factors.

Cellular aging and restorative processes: subjective sleep quality and duration moderate the association between age and telomere length in a sample of middle-aged and older adults.

STUDY OBJECTIVES: To examine whether subjective sleep quality and sleep duration moderate the association between age and telomere length (TL). DESIGN: Participants completed a demographic and sleep quality questionnaire, followed by a blood draw. SETTING: Social Neuroscience Laboratory. PARTICIPANTS: One hundred fifty-four middle-aged to older adults (age 45-77 y) participated. Participants were excluded if they were on immunosuppressive treatment and/or had a disease with a clear immunologic (e.g., cancer) component. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Subjective sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index (PSQI) and TL was determined using peripheral blood mononuclear cells (PBMCs). There was a significant first-order negative association between age and TL. Age was also negatively associated with the self-reported sleep quality item and sleep duration component of the PSQI. A significant age × self-reported sleep quality interaction revealed that age was more strongly related to TL among poor sleepers, and that good sleep quality attenuated the association between age and TL. Moreover, adequate subjective sleep duration among older adults (i.e. greater than 7 h per night) was associated with TL comparable to that in middle-aged adults, whereas sleep duration was unrelated to TL for the middle-aged adults in our study. CONCLUSIONS: The current study provides evidence for an association between sleep quality, sleep duration, and cellular aging. Among older adults, better subjective sleep quality was associated with the extent of cellular aging, suggesting that sleep duration and sleep quality may be added to a growing list of modifiable behaviors associated with the adverse effects of aging.

The stress-buffering effects of functional social support on ambulatory blood pressure.

OBJECTIVE: Social support is a reliable predictor of cardiovascular health. According to the buffering hypothesis, stress is 1 mechanism by which support is able to affect physiological processes. However, most of the experimental evidence for the hypothesis comes from laboratory studies. Ambulatory blood pressure (ABP) protocols examine participants in their natural environment, where they are more likely to encounter personally relevant real-world stressors. Furthermore, prior work shows that examining support by its specific functional components reveals additional independent links to health. METHODS: The current study aimed to examine the stress-buffering effects of functional social support on ABP. One hundred eighty-eight participants completed a 1-day ABP assessment along with measures of functional social support and both global perceived stress and momentary stress at time of reading. RESULTS: RESULTS indicated main effects for both stress measures. Global support, emotional, tangible, and informational support only moderated the effects of momentary stress, but not global stress, in predicting ABP. Informational support was the most consistent stress-buffering predictor of ABP, predicting both ambulatory systolic and diastolic blood pressure. CONCLUSIONS: The predicted values in ABP for informational support achieved health-relevant differences, emphasizing the value of examining functional support beyond global support alone.

Levels of fatigue and distress in senior prostate cancer survivors enrolled in a 12-week randomized controlled trial of Qigong.

PURPOSE: Fatigue is a commonly reported symptom by prostate cancer survivors and is associated with significant distress and declines in quality of life. Qigong is a mind-body activity that consists of both physical activity and meditative aspects. This 12-week randomized controlled trial examined the feasibility and efficacy of a Qigong intervention for improving older prostate cancer survivors' levels of fatigue and distress. METHODS: Forty older (median age = 72, range = 58-93), fatigued (cut-off value of ≥ 1 on the CTCAEv4.0, >20 on a fatigue grading scale), and sedentary (<150 min of moderate exercise/week) prostate cancer survivors were randomized to 12 weeks of Qigong or stretching classes. Primary outcomes were feasibility (i.e., retention and class attendance rates) and fatigue [Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue)], and secondary outcome was distress [Brief Symptom Inventory-18 (BSI-18)]. RESULTS: Study retention rates did not significantly differ between study groups (Qigong = 80 %, stretching = 65 %, p = 0.48). The Qigong group had significantly higher class attendance than the stretching group (p = 0.04). The Qigong group had significantly greater improvements in the FACIT-Fatigue (p = 0.02) and distress (i.e., BSI-18 Somatization, Anxiety, & Global Severity Index, p's < 0.05), than the Stretching group. CONCLUSIONS: This 12-week Qigong intervention was feasible and potentially efficacious in improving senior prostate cancer survivors' levels of fatigue and distress levels. Future, larger definitive randomized controlled trials are needed to confirm these benefits in older prostate cancer survivors and in racially and ethnically diverse populations. IMPLICATIONS FOR CANCER SURVIVORS: Qigong may be an effective nonpharmacological intervention for the management of senior prostate cancer survivors' fatigue and distress.

Exogenously applied muscle metabolites synergistically evoke sensations of muscle fatigue and pain in human subjects.

NEW FINDINGS: What is the central question of this study? Can physiological concentrations of metabolite combinations evoke sensations of fatigue and pain when injected into skeletal muscle? If so, what sensations are evoked? What is the main finding and its importance? Low concentrations of protons, lactate and ATP evoked sensations related to fatigue. Higher concentrations of these metabolites evoked pain. Single metabolites evoked no sensations. This suggests that the combination of an ASIC receptor and a purinergic P2X receptor is required for signalling fatigue and pain. The results also suggest that two types of sensory neurons encode metabolites; one detects low concentrations of metabolites and signals sensations of fatigue, whereas the other detects higher levels of metabolites and signals ache and hot. The perception of fatigue is common in many disease states; however, the mechanisms of sensory muscle fatigue are not understood. In mice, rats and cats, muscle afferents signal metabolite production in skeletal muscle using a complex of ASIC, P2X and TRPV1 receptors. Endogenous muscle agonists for these receptors are combinations of protons, lactate and ATP. Here we applied physiological concentrations of these agonists to muscle interstitium in human subjects to determine whether this combination could activate sensations and, if so, to determine how the subjects described these sensations. Ten volunteers received infusions (0.2 ml over 30 s) containing protons, lactate and ATP under the fascia of a thumb muscle, abductor pollicis brevis. Infusion of individual metabolites at maximal amounts evoked no fatigue or pain. Metabolite combinations found in resting muscles (pH 7.4 + 300 nm ATP + 1 mm lactate) also evoked no sensation. The infusion of a metabolite combination found in muscle during moderate endurance exercise (pH 7.3 + 400 nm ATP + 5 mm lactate) produced significant fatigue sensations. Infusion of a metabolite combination associated with vigorous exercise (pH 7.2 + 500 nm ATP + 10 mm lactate) produced stronger sensations of fatigue and some ache. Higher levels of metabolites (as found with ischaemic exercise) caused more ache but no additional fatigue sensation. Thus, in a dose-dependent manner, intramuscular infusion of combinations of protons, lactate and ATP leads to fatigue sensation and eventually pain, probably through activation of ASIC, P2X and TRPV1 receptors. This is the first demonstration in humans that metabolites normally produced by exercise act in combination to activate sensory neurons that signal sensations of fatigue and muscle pain.

The role of oxytocin in familiarization-habituation responses to social novelty.

Stress or arousal responses to novel social contexts ease off when individuals get familiar with the social context. In the present study we investigated whether oxytocin is involved in this process of familiarization-habituation as oxytocin is known to increase trust and decrease anxiety. Fifty-nine healthy female subjects took part in the same experimental procedure in two sessions separated by 4 weeks. In the first (novelty) session state trust scores were significantly positively correlated with salivary oxytocin levels while in the second (familiarity) session state trust scores were significantly negatively correlated with salivary oxytocin levels. In a path model oxytocin was associated with increased trust in the novelty session and trust was associated with decreased oxytocin levels in the familiarity session. The results are consistent with the idea that oxytocin decreases stress-to-novelty responses by promoting familiarization to novel social contexts.

Dysregulation of leukocyte gene expression in women with medication-refractory depression versus healthy non-depressed controls.

BACKGROUND: Depressive Disorders (DD) are a great financial and social burden. Females display 70% higher rate of depression than males and more than 30% of these patients do not respond to conventional medications. Thus medication-refractory female patients are a large, under-served, group where new biological targets for intervention are greatly needed. METHODS: We used real-time quantitative polymerase chain reaction (qPCR) to evaluate mRNA gene expression from peripheral blood leukocytes for 27 genes, including immune, HPA-axis, ion channels, and growth and transcription factors. Our sample included 23 females with medication refractory DD: 13 with major depressive disorder (MDD), 10 with bipolar disorder (BPD). Our comparison group was 19 healthy, non-depressed female controls. We examined differences in mRNA expression in DD vs. controls, in MDD vs. BPD, and in patients with greater vs. lesser depression severity. RESULTS: DD patients showed increased expression for IL-10, IL-6, OXTR, P2RX7, P2RY1, and TRPV1. BPD patients showed increased APP, CREB1, NFKB1, NR3C1, and SPARC and decreased TNF expression. Depression severity was related to increased IL-10, P2RY1, P2RX1, and TRPV4 expression. CONCLUSIONS: These results support prior findings of dysregulation in immune genes, and provide preliminary evidence of dysregulation in purinergic and other ion channels in females with medication-refractory depression, and in transcription and growth factors in those with BPD. If replicated in future research examining protein levels as well as mRNA, these pathways could potentially be used to explore biological mechanisms of depression and to develop new drug targets.