The GABA system, a new target for medications against cognitive impairment-Associated with neuroactive steroids.

The prevalence of cognitive dysfunction, dementia, and neurodegenerative disorders such as Alzheimer's disease (AD) is increasing in parallel with an aging population. Distinct types of chronic stress are thought to be instrumental in the development of cognitive impairment in central nervous system (CNS) disorders where cognitive impairment is a major unmet medical need. Increased GABAergic tone is a mediator of stress effects but is also a result of other factors in CNS disorders. Positive GABA-A receptor modulating stress and sex steroids (steroid-PAMs) such as allopregnanolone (ALLO) and medroxyprogesterone acetate can provoke impaired cognition. As such, ALLO impairs memory and learning in both animals and humans. In transgenic AD animal studies, continuous exposure to ALLO at physiological levels impairs cognition and increases degenerative AD pathology, whereas intermittent ALLO injections enhance cognition, indicating pleiotropic functions of ALLO. We have shown that GABA-A receptor modulating steroid antagonists (GAMSAs) can block the acute negative cognitive impairment of ALLO on memory in animal studies and in patients with cognitive impairment due to hepatic encephalopathy. Here we describe disorders affected by steroid-PAMs and opportunities to treat these adverse effects of steroid-PAMs with novel GAMSAs.

Altered GABAA receptor function in women with endometriosis: a possible pain-related mechanism.

INTRODUCTION: The mechanism underlying endometriosis-related pain remains poorly understood. Previous studies have indicated that γ-aminobutyric acid (GABA) type A (GABAA ) receptors and GABAergic substances (eg endogenous neurosteroids) play important mechanistic roles in various pain conditions. Our primary objective was to compare GABAA receptor function between women with endometriosis and healthy controls by performing a challenge test with diazepam, a GABAA receptor agonist, using the saccadic eye velocity as the main outcome. The secondary objective was to investigate the relation between GABAA receptor function and serum levels of allopregnanolone, an endogenous positive modulator of the GABAA receptor, in the participating women. MATERIAL AND METHODS: 15 women with pelvic pain and laparoscopically confirmed endometriosis and 10 healthy, symptom-free, control women, aged 18-40 years, underwent the diazepam challenge test during the follicular phase of the menstrual cycle. Basal serum allopregnanolone levels were measured prior to diazepam injection. RESULTS: Compared with healthy controls, women with pelvic pain and confirmed endometriosis had a significantly smaller change in saccadic eye velocity after GABAA receptor stimulation with diazepam, indicating lower sensitivity to diazepam. The saccadic eye velocity response was not correlated with the serum allopregnanolone levels. CONCLUSIONS: Women with painful endometriosis show altered GABAA receptor function, depicted as a muted response to an exogenous GABAA receptor agonist.

Obstetric outcomes after cervical loop electrosurgical excision procedure.

OBJECTIVES: This study aimed to investigate whether a history of loop electrosurgical excision procedure (i.e., conisation) affects obstetric and neonatal outcomes. METHODS: A retrospective cohort study was carried out in Västernorrland county, Sweden. 57 nulliparous women with singleton pregnancies and previous conisation were compared with 100 age-matched pregnant controls without history of conisation. RESULTS: There was significantly lower gestational age by delivery (p = 0.036), however, the premature delivery rate was not different. Caesarean section was also less frequent (OR: 0.29, 95% CI: 0.081-1.04, p = 0.047) in the conisation group than those in the control group. There were no differences in neonatal outcomes. CONCLUSIONS: Previous conisation does not affect the risk of prematurity or cervical dilatation during the first stage of labour. Women with history of conisation had a lower rate of caesarean section, and lower gestational age by delivery.

Hyperandrogenic Symptoms Are a Persistent Suffering in Midlife Women with PCOS; a Prospective Cohort Study in Sweden.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder among women, and the majority suffers from hyperandrogenism. Hyperandrogenism causes psychological morbidity and impaired quality of life in women with PCOS during the reproductive years, but data on prevalence and impact during midlife are lacking. Thus, this study aimed to address whether hyperandrogenism persists into midlife and, if so, what impact it has on quality of life. In order to answer this question, we performed a multicenter prospective cohort study, where we included women already diagnosed with PCOS who had reached the age of 45 years or more and age-matched controls. All participants underwent a physical exam, structured medical interview, biochemical testing and filled out self-assessment questionnaires. More than 40% of the women with PCOS and 82% of those who presented with the hyperandrogenic phenotype at the diagnostic work-up still suffered from hirsutism. Circulating testosterone levels were similar between women with PCOS and controls while free androgen index was higher in women with PCOS, independent of weight. Women with hyperandrogenic PCOS expressed persisting concerns regarding hirsutism at the follow-up assessment. In conclusion, women with PCOS who present with hyperandrogenic symptoms at the time they are diagnosed with PCOS have a higher risk of persistent androgenic symptoms and impaired quality of life in midlife.

Higher risk of type 2 diabetes in women with hyperandrogenic polycystic ovary syndrome.

OBJECTIVE: To assess the risk of type 2 diabetes (T2D) in women with polycystic ovary syndrome (PCOS) in relation to body mass index (BMI) and the hyperandrogenic (HA) PCOS phenotype. DESIGN: Population-based cohort study. SETTING: Data from six Swedish national registers, with participants being followed for a maximum of 19 years. PATIENT(S): All women with an International Statistical Classification of Diseases and Related Health Problems, version 10, diagnosis of PCOS, androgen excess, or anovulatory infertility born between 1950 and 1999 (n = 52,535) were identified in the Patient Register. The HA PCOS phenotype was defined by two filled prescriptions for anti-androgenic drugs. For each woman with PCOS, five control women (n = 254,624) were randomly chosen from the Total Population Register, matched for age and geographic area. INTERVENTION(S): No interventions were performed. MAIN OUTCOME MEASURE(S): International Statistical Classification of Diseases and Related Health Problems, version 10, diagnosis of T2D or prescription of antidiabetic treatment other than metformin. RESULT(S): The cumulative incidence rates of T2D were 1.3%, 4.4%, and 14.2% in controls (non-PCOS women) and women with normoandrogenic (NA) and HA PCOS, respectively. After adjustment for BMI, women with PCOS had a twofold higher rate of T2D than non-PCOS women (adjusted hazard ratio, 2.52 [95% confidence interval, 2.15-2.96]). Women with HA PCOS had a higher rate of T2D than those with NA PCOS (adjusted hazard ratio, 3.86 [95% confidence interval, 3.16-4.72]). CONCLUSION(S): Polycystic ovary syndrome is an independent risk factor for T2D, even after adjustment for BMI. Women with the HA PCOS phenotype face an even higher risk of T2D than those with the NA PCOS phenotype.

Neurosteroid involvement in threatened preterm labour.

Introduction: The neurosteroid allopregnanolone modulates oxytocin expression in the brain, and its effects arise from its action on the GABAA receptor. Whether neurosteroid levels and the function of the GABAA receptor are involved in the risk of preterm labour in pregnant women is unknown. Methods: Pregnant women with (n = 16) or without (n = 20) threatened preterm labour (TPL) in gestational week 33 + 6 days to 37 + 0 days were studied prospectively with procedures including foetal heart rate monitoring, vaginal examination, ultrasound examination and blood tests to determine allopregnanolone, progesterone and oxytocin levels. The GABAA receptor function in both groups was measured with a saccadic eye velocity test (SEVT). Results: Plasma oxytocin levels were higher in the TPL group than in the control group (41.5 vs. 37.0 pmol/L, respectively, p = .021). Although the allopregnanolone and progesterone levels in both groups did not differ, there was a negative association between blood oxytocin and allopregnanolone (as predictor) levels in the TPL group (B: -3.2, 95% confidence interval (CI): -5.5 to -0.9, p = .012). As a predictor of TPL, progesterone was associated with cervix maturity (odds ratio: 1.02, 95% CI: 1.00-1.04, p = .038). SEVT showed that the women in both groups had similar GABAA receptor functions. In both groups, body mass index correlated with peak saccadic eye velocity (r = .34, p = .044) and negatively with allopregnanolone (r = -.41, p = .013). Conclusions: Neurosteroid levels were unchanged in the peripheral blood of women with TPL, despite the increase in available oxytocin. Although the function of the GABAA receptor was unchanged in women with TPL, to ensure reliable results, saccadic eye velocity should be investigated during a challenge test with a GABAA receptor agonist.

Sexuality and mood changes in women with persistent pelvic girdle pain after childbirth: a case-control study.

BACKGROUND: Pelvic girdle pain is a common problem during pregnancy. For most women, the symptoms cease within the first 3-6 months of giving birth, but in some women the pain persists. In this study we investigate the sexuality and frequency of depressive symptoms in women with persistent pelvic girdle pain after childbirth and in healthy women. METHODS: We conducted a case-control study of women with persistent pelvic girdle pain after childbirth and a control group of healthy women. The frequency of depressive symptoms and sexuality were measured using the self-rating version of the Montgomery-Asberg Depression Rating Scale and the McCoy Female Sexuality Questionnaire. RESULTS: Forty-six women with persistent pelvic girdle pain and thirty-nine healthy women were enrolled. The frequency of depressive symptoms and the total score on female sexuality did not differ between the groups. However, pain during intercourse was more frequent (P < 0.001) in women with persistent pelvic girdle pain and caused them to avoid sexual intercourse frequently (P < 0.001). In multiple linear regression a higher frequency of depressive symptoms was reversely correlated with a lower score on female sexuality (ß = - 0,41, p < 0,001 95% CI -0,6 - -0,22) This association remained after adjusting for obstetric variables and individual characteristics. CONCLUSION: Depressive symptoms and female sexuality were similar between women with persistent pelvic girdle pain after childbirth and healthy controls. However, pain during intercourse and avoidance of sexual intercourse were more frequent among women with pelvic girdle pain.

Performance of Variables in Screening for Gestational Diabetes.

Introduction: Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes. The strategies used to screen for GDM vary both internationally and nationally. Therefore, we investigated the performance of the capillary random plasma glucose (RPG) test, maternal body mass index (BMI) and maternal age in predicting GDM. Methods: In a retrospective cohort study, we included pregnant women without pre-existing diabetes or metabolic disease who gave birth in Västernorrland County, Sweden, in 2015-2016. Values for RPG in gestational weeks 23-28 were obtained from obstetric medical records for each pregnancy. The development of GDM was confirmed by evaluating data in the obstetric records. The ability of RPG, maternal BMI, and age to predict GDM was assessed with receiver-operating characteristic curves. Results: In total, 4,698 pregnancies were included in the final statistical analysis. RPG was fairly effective in screening (area under the curve [AUC] 0.73; 95% confidence interval [CI] 0.66-0.80), and BMI performed slightly better (AUC 0.75; 95% CI 0.68-0.82), whereas maternal age performed poorly (AUC 0.61; 95% CI 0.53-0.68). Combining RPG ≥7 and BMI ≥27.9 yielded the best overall sensitivity (75.4%), specificity (70.1%), and AUC (0.75; 95% CI 0.68-0.82). Conclusions: Our results show that the sensitivity of capillary RPG alone in predicting GDM is fair. The combination of RPG with maternal BMI or age showed greater sensitivity. However, none of the screening factors (RPG, BMI, and maternal age), alone or combined, showed sufficiently good performance in predicting GDM.

Foetal Macrosomia and Foetal-Maternal Outcomes at Birth.

To investigate how macrosomia affects foetal-maternal birth outcomes, we conducted a retrospective cohort study of singleton pregnant women who gave birth at gestational age ≥37+0 weeks. The patients were divided into three groups according to birth weight: "macrosomia" group, ≥4500 g, n=285; "upper-normal" group, 3500-4499 g, n=593; and "normal" group, 2500-3499 g, n=495. Foetal-maternal and delivery outcomes were compared among the three groups after adjustment for confounders. Caesarean section was more frequent in the macrosomia group than in upper-normal and normal groups. The duration of labour (p < 0.05) and postpartum care at the hospital (p < 0.001) were the highest in the macrosomia group. Increased birth weight was associated with higher risks of shoulder dystocia (p < 0.001), increased bleeding volume (p < 0.001), and perineal tear (p < 0.05). The Apgar score at 5 minutes (p < 0.05), arterial cord pH (p < 0.001), and partial pressure of O2 (p < 0.05) were lower, while the arterial cord partial pressure of CO2 was higher (p < 0.001), in the macrosomia group. Macrosomia has potentially serious impacts for neonate and mother as a result of a complicated and occasionally traumatic delivery.

Post-partum duration of satisfaction with childbirth.

AIM: Satisfaction with childbirth has become increasingly important among healthcare providers. We evaluated whether satisfaction levels change with time (up to 3 months after delivery). METHODS: A prospective study of nulliparous women was designed to evaluate their levels of satisfaction with childbirth and care during birth in the maternity unit of a county hospital in Sundsvall, Sweden. Patient satisfaction with birth and health care was measured twice, during the first week after birth and 3 months later, with the Childbirth Experience Questionnaire (CEQ). Maternal and labor information were collected with a form filled in by the patients and completed with information from the patients' records. RESULTS: A total of 78 primiparous women participated in the study and answered the questionnaire in the first week after labor, and 63 of them completed the study by answering the same questionnaire 3 months after delivery. The total CEQ score did not change after 3 months, but the scores for the subscales 'professional support' and 'participation' decreased 3 months after labor (P = 0.008 and P = 0.001, respectively). A visual analogue scale predicted the total CEQ scores at both 1 week (P < 0.001) and 3 months (P = 0.003). CONCLUSION: Our results indicate that satisfaction with labor and birth among primiparous women was unchanged 3 months after labor.

Fetal-maternal outcomes and complications in pregnant women with polycystic ovary syndrome.

BACKGROUND: Earlier studies have shown that polycystic ovary syndrome (PCOS) is associated with cardiovascular disease as well as pregnancy complications. We examined whether women with PCOS have an increased risk of complications in pregnancy compared with healthy women, and if there are any correlations between complications and clinical/demographic variables before and/or in early pregnancy. METHODS: This retrospective cohort study comprised 37 women with PCOS and 126 healthy women whose birth was recorded at Sundsvall County Hospital, Sweden, from 2009 to 2014. Medical records were searched to identify pregnancy complications, maternal outcomes, and neonatal outcomes. RESULTS: Compared with healthy women, the women with PCOS were more likely to have a history of miscarriage (42.9% vs. 19.8% P=0.005) and undergo caesarean section (41.2% vs. 21.4%, P=0.019). They were also at increased risk of developing a complication (odds ratio 2.38, 95% CI: 1.05-5.38) or having multiple concurrent complications (odds ratio 8.27, 95% CI: 1.45-47.3). The rates of premature birth, birth weight and Apgar score at 5 min were similar between the two groups. The preconception serum testosterone concentration was positively correlated with the complication rate and negatively correlated with gestational age. CONCLUSIONS: We found that women with PCOS are at greater risk of complications during pregnancy than healthy women, consistent with the results of earlier studies. High testosterone concentrations could be an aggravating factor in the risk of complications. Therefore, women with PCOS may require more careful monitoring during pregnancy than healthy women.

Roux-en-Y Gastric Bypass Surgery in Patients with Polycystic Ovary Syndrome and Metabolic Syndrome.

BACKGROUND: We aimed to evaluate the impact of Roux-en-Y gastric bypass (RYGB) surgery on metabolic syndrome-related variables in obese women with polycystic ovarian syndrome (PCOS). METHODS: Thirteen obese women with PCOS (Rotterdam criteria) who met the International Diabetes Federation criteria for metabolic syndrome and who qualified for RYGB were enrolled. Clinical examinations included ovarian ultrasonography and measurement of waist, hip, body mass index and blood pressure. Venous blood samples were taken at the visit before surgery to measure triglyceride, high-density lipoprotein, low-density lipoprotein, fasting glucose, glycated haemoglobin (HbA1c), serum progesterone, allopregnanolone, total testosterone and sex hormone-binding globulin (SHBG) levels. Six months after surgery, patients underwent the same examinations and provided blood samples to analyse the same variables. RESULTS: At 6 months after surgery, the metabolic syndrome-related variables improved in all patients, except in six patients with anovulatory menstrual cycles who still satisfied the criteria for metabolic syndrome. The metabolic variables normalised and serum progesterone and allopregnanolone levels increased in seven patients with ovulatory cycles. Testosterone and SHBG normalised in all patients at 6 months after surgery. Serum HDL and diastolic blood pressure did not change after surgery. Correlations were found among testosterone, progesterone, allopregnanolone, lipoproteins, triglyceride, fasting glucose and HbA1c levels, which was interpreted as progesterone and its metabolite allopregnanolone may contribute to metabolic abnormalities. CONCLUSIONS: In PCOS patients, normalisation of metabolic dysfunction may be incomplete by 6 months after RYGB surgery, and the start of ovulatory menstrual cycles may indicate normalisation of metabolic dysfunction.

Women with polycystic ovary syndrome have elevated serum concentrations of and altered GABA(A) receptor sensitivity to allopregnanolone.

OBJECTIVE: Several studies have reported that γ-aminobutyric acid (GABA) ergic circuits are involved in the pathophysiology of polycystic ovary syndrome (PCOS). The progesterone metabolite allopregnanolone is a potent GABA(A) -receptor-modulating steroid, and patients may have increased concentrations of allopregnanolone or altered GABAA receptor sensitivity. We investigated both of these possibilities in this study. PATIENTS: We enrolled 9 women with PCOS and 24 age-matched eumenorrhoeic controls, who were divided into two groups by body mass index (BMI) (16 normal weight and 8 overweight). MEASUREMENTS: We investigated the effects of allopregnanolone injection on GABA(A) receptor sensitivity in both groups of women. All women received a single intravenous dose of allopregnanolone (0·050 mg/kg). GABA(A) receptor sensitivity was assessed with the saccadic eye velocity (SEV) over 30° (SEV30°), the SEV30°/allopregnanolone concentration ([Allo]) ratio, and sedation, which were measured together with serum allopregnanolone at intervals for 180 min after injection. The controls were tested in the follicular phase of the menstrual cycle. RESULTS: Baseline allopregnanolone concentrations were higher in the PCOS women than in the normal-weight (P = 0·034) and overweight controls (P = 0·004). The allopregnanolone concentrations after injection were higher in the PCOS women (P = 0·006) and overweight controls (P = 0·037) than in the normal-weight controls. All groups showed a decline in the SEV30°/[Allo] ratio after injection. Allopregnanolone had a smaller effect on the SEV30°/[Allo] ratio in the overweight women (PCOS, P = 0·032; controls, P = 0·007) than in the normal-weight controls. The sedation score after allopregnanolone injection was lower in the PCOS patients than in the controls, but was not different between the two control groups. CONCLUSIONS: PCOS women had elevated baseline allopregnanolone concentrations compared with follicular-phase controls. All overweight women (PCOS and controls) were less sensitive to allopregnanolone than normal-weight controls.

Maternal and neonatal outcomes in vacuum-assisted delivery with the Kiwi OmniCup and Malmström metal cup.

AIM: To evaluate the effects of different types of vacuum cups on maternal and neonatal outcomes following assisted vaginal delivery. METHODS: A retrospective cohort study was undertaken of all vacuum-assisted deliveries performed over a period of 2 years. Patients were divided into two groups according to whether a Kiwi OmniCup (n = 230) or Malmström metal cup (n = 98) was used. Maternal outcomes included maternal genital tract injury and total blood loss. Neonatal outcomes included Apgar score, umbilical cord blood gases, neonatal scalp injury and time spent in the neonatal unit. RESULTS: Maternal or neonatal outcomes and failure rates did not differ between the two groups, however, the duration of the procedure and the fundal pressure maneuver was more frequent in the Malmström group. CONCLUSION: The results of this study suggest that the Kiwi OmniCup and Malmström metal cup vacuum extractors are safe and functionally effective for vacuum-assisted delivery.

Effects of Roux-en-Y gastric bypass surgery on eating behaviour and allopregnanolone levels in obese women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is associated with abnormal eating habits. We examined whether surgical treatment affected allopregnanolone levels and eating behaviour in nine women with PCOS who qualified for Rou-en-Y gastric bypass surgery. Blood samples were obtained to measure sex-hormone-binding globulin, total testosterone, progesterone, and allopregnanolone, and eating behaviour was evaluated using the Three-Factor Eating Questionnaire before surgery and at 6 and 12 months after surgery. Body mass index and total testosterone levels decreased, and progesterone and sex-hormone-binding globulin levels increased after bariatric surgery compared with pre-surgical values. In patients with anovulatory menstrual cycles, both the serum allopregnanolone level and the allopregnanolone/progesterone ratio were unchanged after surgery. The patients had high uncontrolled and emotional eating scores, and low cognitive restraint scores before surgery, and these scores had improved significantly at 6 and 12 months after surgery. The presurgical allopregnanolone levels were significantly correlated with uncontrolled eating. In conclusion, these results suggest that allopregnanolone appear to be part of the mechanism underlying the abnormal eating behaviour of obese PCOS patients by causing the loss of control over food intake. Roux-en-Y gastric bypass surgery can improve eating behaviour and clinical symptoms, and may facilitate weight loss in obese women with PCOS.

Sexuality and androgens in women with cyclical mood changes and pre-menstrual syndrome.

OBJECTIVE: To study the relation between androgen levels and sexual interest in women with different kinds of pre-menstrual syndrome (PMS). DESIGN: Causal comparative study. SETTING: Swedish university hospital outpatient clinic. POPULATION: Seventy women with cyclical mood changes. METHODS: Pre-menstrual syndrome patients were divided into those with and those without preovulatory symptoms. In 37 women, early follicular phase blood samples were analyzed for androstenedione, testosterone, sex hormone-binding globulin (SHBG), progesterone and estradiol, using radioimmunoassay. The participants were divided into subgroups depending on whether the levels of androgens and SHBG were above or below the median. In 33 of them it was possible to compare the cyclicity in sexual parameters between these subgroups. MAIN OUTCOME MEASURES: Daily ratings of sexual parameters and hormonal analyses. RESULTS: Plasma testosterone was significantly lower and SHBG significantly higher in women with luteal phase symptoms compared with those with additional follicular phase symptoms. ANOVA showed significant cyclicity for all sexual parameters consistently. For the "sexual feelings" and "pleasant sexual thoughts" parameters, cyclicity was the same whether or not the hormonal levels were "high" or "low." CONCLUSIONS: The "Pure-PMS" group and the "pre-menstrual-exacerbation" groups differed in their androgen and SHBG levels. Women suffering from PMS with higher neuroticism Eysenck Personality Inventory scores or "low" levels of androgens and SHBG would be more likely to have a decreased sexual interest pre-menstrually than would women with a high level.

Tolerance to allopregnanolone with focus on the GABA-A receptor.

Many studies have suggested a relationship between stress, sex steroids, and negative mental and mood changes in humans. The progesterone metabolite allopregnanolone is a potent endogenous ligand of the γ-amino butyric acid -A (GABA-A) receptor, and the most discussed neuroactive steroid. Variations in the levels of neuroactive steroids that influence the activity of the GABA-A receptor cause a vulnerability to mental and emotional pathology. There are physiological conditions in which allopregnanolone production increases acutely (e.g. stress) or chronically (e.g. menstrual cycle, pregnancy), thus exposing the GABA-A receptor to high and continuous allopregnanolone concentrations. In such conditions, tolerance to allopregnanolone may develop. We have shown that both acute and chronic tolerances can develop to the effects of allopregnanolone. Following the development of acute allopregnanolone tolerance, there is a decrease in the abundance of the GABA-A receptor α4 subunit and the expression of the α4 subunit mRNA in the ventral-posteriomedial nucleus of the thalamus. Little is known about the mechanism behind allopregnanolone tolerance and its effects on assembly of the GABA-A receptor composition. The exact mechanism of the allopregnanolone tolerance phenomena remains unclear. The purpose of this review is to summarize certain aspects of current knowledge concerning allopregnanolone tolerance and changes in the GABA-A receptors.

Withdrawal effects from progesterone and estradiol relate to individual risk-taking and explorative behavior in female rats.

Withdrawal from progesterone and estradiol has been used as an animal model of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). In the clinical population individual sensitivity to sex steroid hormones, personality and heredity influence PMS/PMDD. Understanding the phenotypic risk factors of PMS/PMDD and drug development requires an animal model which incorporates individual steroid sensitivity. The main objective of this study was to investigate whether the individual trait of risk-taking and exploration influence the severity of PEWD in female rats. Thirty-two female Wistar rats in their diestrus phase were tested in the open field (OF) and divided into high responders (HR) and low responders (LR). Injections were given i.p. twice daily for 6 days, either 5 mg/kg progesterone combined with 10 microg/kg 17beta-estradiol, or vehicle (sesame oil). After a 24-hour withdrawal the animals were tested in the elevated plus maze (EPM). Blood samples for CORT analysis were collected after both behavioral tests. The HR rats withdrawn from progesterone and estradiol, spent less time on the EPM open arms and had lower CORT levels than the HR controls. The LR group showed no differences in EPM behavior and CORT levels during PEWD. The controls showed a stable trait of risk-taking and exploration, indicated by behavioral and CORT level correlations between the OF and EPM tests. These findings show that female rats with the trait of risk-taking and explorative behavior (HR) are more affected by PEWD.

Persistence of tolerance to the anaesthetic effect of allopregnanolone in male rats.

Both acute and chronic tolerance can develop to allopregnanolone-a gamma-aminobutyric acid (GABA)-modulatory progesterone metabolite. Here we investigated if acute tolerance to allopregnanolone persisted for 1 or 2 days after the induction and thus could be the initial part of chronic tolerance. Male rats were anaesthetised with allopregnanolone (i.v) to the deep anaesthesia level of the silent second (SS), which is an EEG burst suppression of 1 s or more. They were divided into four groups: SS1-anaesthesia to the first silent second; LAn (long anaesthesia)-90 min anaesthesia at the SS level; SS2;D1-90 min anaesthesia and SS induction 1 day later; SS2;D2-90 min anaesthesia and SS induction 2 days later. Allopregnanolone concentrations in tissue and serum were analysed. Levels of the GABAA receptor alpha2, alpha4, gamma2(S+L) and delta subunits mRNAs were analysed by in situ hybridisation. Acute tolerance was induced during the 90 min anaesthesia. Tolerance persisted for 1 day, since the dose of allopregnanolone needed to induce a new SS anaesthesia was increased after 1 day. The level of alpha4 subunit mRNA expression in the ventral posteriomedial nucleus of thalamus was negatively related to the tolerance parameters, the SS dose of allopregnanolone and DeltaSS (SS dose difference between days). Allopregnanolone threshold anaesthesia lasting 90 min induces acute tolerance that persisted for at least 1 day, which could be used as the start of a chronic tolerance. The alpha4 subunit may be involved in allopregnanolone caused effects in the brain.