Alterations in platelet serotonin transporter binding in women with postpartum onset major depression

Association between gut microbiota and postpartum depression: A bidirectional Mendelian randomization study

BACKGROUNDS

Empirical investigations have shown an association between gut microbiota and postpartum depression (PPD); nevertheless, the precise cause-and-effect relationship between these two variables remains ambiguous. This research aimed to examine the possible reciprocal causal relationship between the gut microbiota and PPD.

METHODS

In this work, we used Mendelian randomization (MR) to analyze the relationship between the gut microbiota (n = 18,340) and PPD (n = 67,205). We obtained the relevant SNPs from publicly accessible genome-wide association studies (GWAS). The SNP estimations were combined by the inverse-variance weighted (IVW) method, including sensitivity analyses such as weighted median, MR Egger, and MR Pleiotropy Residual Sum and Outlier (PRESSO).

RESULTS

We have identified strong correlations between six bacterial characteristics and the likelihood of developing PPD. Our research revealed that the genus Ruminococcaceae UCG010, the family Veillonellaceae, and the class Clostridia had a beneficial effect on preventing PPD. The class Alphaproteobacteria, genus Slackia, and order NB1n were found to have a significant negative impact on PPD. The sensitivity studies conducted on these bacterial features consistently confirmed these finding.

LIMITATIONS

It is crucial to acknowledge that our study was conducted just within a European society, which may restrict its applicability to other groups.

CONCLUSIONS

The findings from our MR investigation indicate a potential causal relationship between certain kinds of gut bacteria and PPD. Additional investigation is required to elucidate the influence of gut microbiota on the advancement of PPD.

Postpartum Depression: Etiology, Treatment, and Consequences for Maternal Care

Postpartum depression (PPD) is a disabling condition that has recently shown an increase in prevalence, becoming an essential public health problem. This study is a qualitative review summarizing the most frequent risk factors associated with PPD, evaluating molecular aspects of PPD and current approaches to detect and prevent PPD. The most prevalent risk factors were detected in the areas of economic and social factors, obstetrical history, lifestyle, and history of mental illness. Research on the genetic basis for PPD has taken place in recent years to identify the genes responsible for establishing targeted therapeutic methods and understanding its pathogenesis. The most frequently studied candidate gene was the serotonin transporter gene (SERT) associated with PPD. Among biological studies, antidepressants and psychological interventions provided the most evidence of successful intervention. The obstetrician can serve an essential role in screening for and treating PPD. Postpartum women with risk factors should be screened using the Edinburgh Postnatal Depression Scale (EPDS), but, at the moment, there are no prevention programs in Europe. In conclusion, data from this review increase concerns among this vulnerable population and can be used to design a screening tool for high-risk pregnant women and create a prevention program.

The role of gut microbiota in the pathogenesis and treatment of postpartum depression

Postpartum depression (PPD) is a common complication of pregnancy in women, and its pathogenesis mainly involves disturbances of the neuroendocrine regulation, immune system, neurotransmitters, hormone secretion, and the gut microbiome. Gut microbes play essential physiological and pathological roles in the gut-brain axis' pathways which are involved in various central nervous system (CNS) and psychiatric disorders, including PPD. Numerous studies have identified the fundamental role of the gut-brain axis in the pathogenesis and treatment of PPD patients and also correlates with other pathogenic mechanisms of PPD. Disturbances in gut microbes are associated with the disruption of multiple signaling pathways and systems that ultimately lead to PPD development. This review aimed to elucidate the potential connections between gut microbes and the established PPD network, and this might serve as a guide for the development of new efficient diagnostic, therapeutic, and prognostic strategies in the management of PPD.

Precision medicine in perinatal depression in light of the human microbiome

Perinatal depression is the most common complication of pregnancy and affects the mother, fetus, and infant. Recent preclinical studies and a limited number of clinical studies have suggested an influence of the gut microbiome on the onset and course of mental health disorders. In this review, we examine the current state of knowledge regarding genetics, epigenetics, heritability, and neuro-immuno-endocrine systems biology in perinatal mood disorders, with a particular focus on the interaction between these factors and the gut microbiome, which is mediated via the gut-brain axis. We also provide an overview of experimental and analytical methods that are currently available to researchers interested in elucidating the influence of the gut microbiome on mental health disorders during pregnancy and postpartum.

Antidepressant Effect of Tetragonia tetragonoides (Pall.) Kuntze Extract on Serotonin Turnover

Tetragonia tetragonoides (Pall.) Kuntze (TTK) is a groundcover found along coastal areas of the Korean peninsula. TTK is traditionally used to improve women's health and treat gastrointestinal diseases. Use of herbal medicines in the treatment of mood disorders has recently been suggested as an alternative therapeutic strategy. In the present study, we determined that consumption of TTK extract ameliorated progression of depressive-like symptoms in ovariectomized (OVX) rats and further examined the mechanisms involved, i.e., synthesis, release, and reuptake(s) of serotonin (also known as 5-HT). We assessed the mRNA expression levels of tryptophan hydroxylases (TPH-1 and TPH-2) and serotonin transporter (SERT) as well as the reuptake activity of serotonin in RBL-2H3 cells. We also determined whether or not TTK extract regulates the serum level of serotonin and improves depressive-like symptoms in 0.5, 1, and 2% TTK-fed OVX female rats in a forced swimming test. Our results show that the mRNA levels of TPH-1 and SERT were significantly reduced, whereas the mRNA level of TPH-2 was dose-dependently elevated by TTK (50 and 100 μg/mL) in RBL-2H3 cells. TTK significantly inhibited LPS- (lipopolysaccharide-) induced serotonin uptake in RBL-2H3 cells in a dose-dependent manner. The serum level(s) of serotonin was elevated by 1% and 2% TTK treatment in OVX female rats. Moreover, immobility time in the forced swimming test was reduced by 1% and 2% TTK treatment but not altered by 0.5% TTK treatment in OVX female rats. Taken together, these results indicate that TTK may significantly inhibit depressive-like symptoms due to upregulation of serotonin level(s) and regulation of serotonin reuptake activity. Thus, TTK may exert beneficial effects on depression during pre- or/and postmenopausal periods via modulation of serotonin synthesis and metabolism.

The role of tryptophan metabolism in postpartum depression

The Postpartum depression (PPD) is the most common postpartum psychiatric disorder, afflicting approximately 10%-20% of new mothers. Clinical symptoms of the PPD include depressive disorder, agitation, insomnia, anxiety and confusion, resulting in an increase in suicidal tendencies, thereby having significant impacts on the puerpera, newborn and their family. A growing body of data indicate a role for alterations in tryptophan metabolism in the PPD. The metabolism of tryptophan produces an array of crucial factors that can differentially regulate key physiological processes linked to the PPD. Importantly, an increase in stress hormones and immune-inflammatory activity drives tryptophan to the production of neuroregulatory kynurenine pathway products and away from the serotonin and melatonin pathways. This links the PPD to other disorders of depressed mood, which are classically associated with decreased serotonin and melatonin, coupled to increases in kynurenine pathway products. Several kynurenine pathway products, such as kynurenic acid and quinolinic acid, can have neuroregulatory effects, with consequences pathological underpinnings of the PPD. The current article reviews the role of alterations in tryptophan metabolism in the PPD.

Parallels between Postpartum Disorders in Humans and Preweaning Piglet Mortality in Sows

Simple Summary

Humans and sows are both highly social species that exhibit a wide variety of maternal behaviors and responsivity to pregnancy and parturition. Piglet crushing is a production and welfare concern for the swine industry. Similar to rates of postpartum depression in humans, the performance of piglet crushing is more likely in first-time mothers. Furthermore, hormonal profiles and social factors that influence the development of this disease in humans mirror those observed in sows surrounding parturition. This article reviews the biological, social, and management factors that may be contributing to this problem of piglet crushing through the lens of how postpartum depression develops in humans. Utilizing knowledge from human psychology and animal welfare science may provide producers with management tools to mitigate piglet crushing and provide new insight into the factors that contribute to human postpartum disorders.

Abstract

Pregnancy and parturition in all mammals is accompanied with physical, psychological, social, and hormonal shifts that impact the mother physically and psychologically. Pre-weaning piglet mortality continues to be a major welfare and economic issue in U.S. swine production, running at 12–15% with crushing by the sow the major cause. Much research has focused on farrowing environment design, yet the fact that little progress has been made emphasizes that psychosocial factors may impact rates of postpartum disorders (PPD). There is a mismatch between evolved adaptations and contemporary psychosocial and management practices. Many factors associated with the development of PPD in humans are mirrored in sows that perform piglet crushing. These factors include poor mental welfare (anxiety, difficulty coping with stress), a lack of experience, a lack of social support, and individual differences in their sensitivity to hormone concentrations. Understanding what strategies are effective in preventing PPD in humans may have welfare and production benefits for sows—and sows may be a possible model for better understanding PPD in humans.

Postpartum Lactation-Mediated Behavioral Outcomes and Drug Responses in a Spontaneous Mouse Model of Obsessive-Compulsive Disorder

Using a spontaneous mouse model of obsessive-compulsive disorder (OCD), the current study evaluated the influence of postpartum lactation on the expression of compulsive-like behaviors, SSRI effectiveness, and the putative role of oxytocin and dopamine in mediating these lactation specific behavioral outcomes. Compulsive-like lactating mice were less compulsive-like in nest building and marble burying and showed enhanced responsiveness to fluoxetine (50 mg/kg) in comparison to compulsive-like nonlactating and nulliparous females. Lactating mice exhibited more anxiety-like behavior in the open field test compared to the nulliparous females, while chronic fluoxetine reduced anxiety-like behaviors. Blocking the oxytocin receptor with L368-899 (5 mg/kg) in the lactating mice exacerbated the compulsive-like and depression-like behaviors. The dopamine D2 receptor (D2R) agonist bromocriptine (10 mg/kg) suppressed marble burying, nest building, and central entries in the open field, but because it also suppressed overall locomotion in the open field, activation of the D2R receptor may have inhibited overall activity nonspecifically. Lactation- and fluoxetine-mediated behavioral outcomes in compulsive-like mice, therefore, appear to be partly regulated by oxytocinergic mechanisms. Serotonin immunoreactivity and serum levels were higher in lactating compulsive-like mice compared to nonlactating and nulliparous compulsive-like females. Together, these results suggest behavioral modulation, serotonergic alterations, and changes in SSRI effectiveness during lactation in compulsive-like mice. This warrants further investigation of postpartum events in OCD patients.

An analysis of the influence of selected genetic and hormonal factors on the occurrence of depressive symptoms in late-reproductive-age women

BACKGROUND

The aim of this study was to analyze the influence of genetic and hormonal factors on incidences of depressive symptoms in late-reproductive-age women.

METHODS

The study was performed using the Beck Depression Inventory, the PCR, and genetic tests of 347 healthy late-reproductive-age Polish women.

RESULTS

The relationship between the level of anti-Müllerian hormone (AMH) and depressive symptoms was not statistically significant (p > 0.05). Increases in age and FSH levels were accompanied by a decrease in AMH level in a significant way (p < 0.05). There were no statistically significant relationships between the distribution of genotypes and the frequency of alleles of the investigated polymorphisms and depressive symptoms according to the Beck Depression Inventory.

CONCLUSIONS

(1) The presence of the s/s genotype of the 5-HTTLPR polymorphism in the serotonin transporter promoter region and the 3/3 genotype of the 30-bp VNTR polymorphism in the monoamine oxidase A promoter region does not contribute to the development of depressive symptoms in late-reproductive-age women. (2) A relationship between the level of anti-Müllerian hormone and depressive symptoms was not confirmed in the group of healthy late-reproductive-age women. (3) AMH level correlates negatively with FSH level and age, which confirms that AMH can be regarded as a factor reflecting the ovarian reserve.

Enhanced responsiveness to selective serotonin reuptake inhibitors during lactation

The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence has cast doubt on the effectiveness of SSRIs, these results support their therapeutic use in the treatment of PPD.

The 5HTT and MAO-A polymorphisms associate with depressive mood and climacteric symptoms in postmenopausal women

OBJECTIVE

The aim of this study was to assess the influence of the 44-bp polymorphism in the 5HTTLPR (SLC 6A4) (serotonin-transporter-linked polymorphic region, solute carrier family 6 member 4) promoter region and the 30-bpVNTR (variable number of tandem repeats) polymorphism in the MAO-A (monoamine oxidase A) promoter region on the prevalence of depressive mood and the severity of climacteric symptoms in postmenopausal women.

MATERIAL AND METHODS

The study involved 630 women from northern Poland who had their last menstrual period at least one year before the study. The women did not abuse alcohol or cigarettes, had not been diagnosed as having endocrinological, cancerous or mental diseases, and had not received psychiatric treatment by the time. This survey-based study was performed using the following research instruments: the Beck Depression Inventory (BDI), to evaluate depressive symptoms, and the Blatt-Kupperman Menopausal Index, to measure the severity of climacteric symptoms.

RESULTS

The average age of the women was 57.5 ± 6.4 years. Depressive symptoms of different severity according to the BDI were diagnosed in 29.2% of the women (minor-18.6%, moderate-7.1%, severe-3.5%) and according to the Blatt-Kupperman Menopausal Index were diagnosed in 42% of the women (minor-24.1%, moderate-9.2%, severe-8.7%). Allele 'l' was significantly more common in the women without climacteric symptoms than those with minor, moderate or severe climacteric complaints (p ≤ 0.05). There was a significant correlation between the severity of climacteric and depressive symptoms (p ≤ 0.05). The women who had severe climacteric symptoms also had more severe depressive symptoms.

CONCLUSIONS

1. The 5HTTLPR gene polymorphism contributes to climacteric symptoms in postmenopausal women. 2. The Blatt-Kupperman Menopausal Index is an instrument which can not only be used for the measurement of the severity of climacteric symptoms but also the early detection of perimenopausal women at the risk of developing depressive symptoms.

Biological aspects of postpartum depression

In comparison with the vast epidemiological literature on postpartum depression (PPD), relatively few studies have examined the biological aspects of the disorder. However, research into the biological mechanisms of PPD is a challenging task, as normal pregnancy and the postpartum period cause adaptive endocrine changes, which would otherwise be considered pathological in nonpregnant women. This review focuses on the adaptive changes of childbearing and nursing, which ultimately may put women at increased risk of PPD. In light of the normal physiology, the authors also attempt to describe the current evidence of the biological changes associated with the development of depression in the postpartum period, including ovarian steroids, the hypothalamic-pituitary-adrenal axis, the serotonergic neurotransmitter system, the thyroid system and inflammatory markers. In addition, current knowledge on candidate genes associated with PPD is reviewed.

Emerging risk factors for postpartum depression: serotonin transporter genotype and omega-3 fatty acid status

OBJECTIVE

Depression is a leading cause of disability and hospitalization. Women are at the highest risk of depression during their childbearing years, and the birth of a child may precipitate a depressive episode in vulnerable women. Postpartum depression (PPD) is associated with diminished maternal somatic health as well as health and developmental problems in their offspring. This review focuses on 2 PPD risk factors of emerging interest: serotonin transporter (5-HTT) genotype and omega-3 polyunsaturated fatty acid (n-3 PUFA) status.

METHOD

The MEDLINE, PubMed, and Web of Science databases were searched using the key words postpartum depression, nutrition, omega-3 fatty acids, and serotonin transporter gene. Studies were also located by reviewing the reference lists of selected articles.

RESULTS

Seventy-five articles were identified as relevant to this review. Three carefully conducted studies reported associations between the 5-HTT genotype and PPD. As well, there is accumulating evidence that n-3 PUFA intake is associated with risk of PPD. Preliminary evidence suggests that there could be an interaction between these 2 emerging risk factors. However, further studies are required to confirm such an interaction and to elucidate the underlying mechanisms.

CONCLUSIONS

Evidence to date supports a research agenda clarifying the associations between n-3 PUFAs, the 5-HTT genotype, and PPD. This is of particular interest owing to the high prevalence of poor n-3 PUFA intake among women of childbearing age and the consequent potential for alternative preventive measures and treatments for PPD.

A serotonin transporter gene polymorphism predicts peripartum depressive symptoms in an at-risk psychiatric cohort

BACKGROUND

Peripartum major depressive disorder (MDD) is a prevalent psychiatric disorder with potential detrimental consequences for both mother and child. Despite its enormous health care relevance, data regarding genetic predictors of peripartum depression are sparse. The aim of this study was to investigate associations of the serotonin-transporter linked polymorphic region (5-HTTLPR) genotype with peripartum MDD in an at-risk population.

METHODS

Two hundred and seventy four women with a prior history of MDD were genotyped for 5-HTTLPR and serially evaluated in late pregnancy (gestational weeks 31-40), early post-partum (week 1-8) and late post-partum (week 9-24) for diagnosis of a current major depressive episode (MDE) and depressive symptom severity.

RESULTS

5-HTTLPR S-allele carrier status predicted the occurrence of a MDE in the early post-partum period only (OR=5.13, p=0.017). This association persisted despite continued antidepressant treatment.

CONCLUSIONS

The 5-HTTLPR genotype may be a clinically relevant predictor of early post-partum depression in an at-risk population.

OBJECTIVE

Peripartum major depressive disorder is a prevalent psychiatric disorder with potential detrimental consequences for both mother and child. Despite its enormous health care relevance, data regarding genetic predictors of peripartum depression are sparse. The aim of this study was to investigate associations of the serotonin-transporter linked polymorphic region (5-HTTLPR) genotype with peripartum MDD in an at-risk population.

Postpartum depression

Postpartum depression (PPD) affects up to 15% of mothers. Recent research has identified several psychosocial and biologic risk factors for PPD. The negative short-term and long-term effects on child development are well-established. PPD is under recognized and under treated. The obstetrician and pediatrician can serve important roles in screening for and treating PPD. Treatment options include psychotherapy and antidepressant medication. Obstacles to compliance with treatment recommendations include access to psychotherapists and concerns of breastfeeding mothers about exposure of the infant to antidepressant medication. Further research is needed to examine systematically the short-term and long-term effect of medication exposure through breastmilk on infant and child development.

Platelet serotonin level and its correlation with finger length relation

BACKGROUND

Serotonin is one of the neurotransmitters implicated in normal personality. Many psychobiological models of personality include some dimensions related to serotonin. Moreover, platelets have long been proposed as easily obtainable, neurological models of serotonergic neurons.

AIM

This study was done to examine whether measurement for platelet serotonin could aid as a marker for increased neuroticism trait amongst (arbitrarily named Group C) males and females having the tip of the little fingers below the distal finger mark on the adjacent ring fingers in both their outstretched hands compared to (arbitrarily named Group A) the males and females who have the tip of the little fingers above the distal finger mark on the adjacent ring fingers in both their outstretched hands.

MATERIALS AND METHODS

Platelet serotonin estimation was done by Elisa Method (LDN, Germany Kit) from randomly selected 48 healthy subjects [24 males (12 males belonging to Group A and 12 belonging to Group C) and 24 females (12 females belonging to group A and 12 females belonging to Group C)].

RESULTS

PRELIMINARY RESULTS SHOWED THAT THE PLATELET SEROTONIN LEVELS WERE SIGNIFICANTLY LOWER (LEVEL OF SIGNIFICANCE: 0.05 in t-Test analysis) in Group C males compared to those observed in Group A males and the platelet serotonin levels were also significantly lower (level of significance: 0.05 in t-Test analysis) in Group C females compared to those observed in Group A females.

CONCLUSION

Thus, it may be inferred that the platelet serotonin may be used as a biochemical marker for increased neuroticism trait in Group C subjects.

Sequential serotonin and noradrenalin associated processes involved in postpartum blues

OBJECTIVE

We investigated whether postpartum blues was related to changes in parameters of noradrenergic and serotonergic functioning.

METHODS

From 26 healthy pregnant women blood was collected at the end of pregnancy and 5 days and 6 weeks postpartum. Serotonergic parameters were: platelet serotonin content; paroxetine binding to platelet membranes as an index of serotonin transporter activity; the serotonin precursor tryptophan in proportion to the large neutral amino acids, as an estimate of its cerebral influx. Noradrenergic indices were the noradrenaline precursor tyrosine and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG). The Kennerly and Gath blues questionnaire was applied at day five postpartum.

RESULTS

The incidence of postpartum blues was 30%. The tryptophan ratio and serotonin content of platelets were decreased (p<0.01) at day five postpartum in all women. Bmax paroxetine at day five was correlated with blues score (beta=0.460; p=0.031). MHPG levels at 6 weeks were increased in women with blues (p<0.001). In a regression model MHPG at 6 weeks was related to blues score (beta=0.477; p=0.002) and MHPG at day five (beta=0.550; p=0.001), explaining >50% of the variation (R2=0.588; p<0.001).

CONCLUSIONS

A decreased serotonergic activity was found at the fifth day postpartum in all subjects. Increased SERT activity, reflected by higher paroxetine binding to platelets might be involved in the onset of blues. The elevated MHPG levels in women with blues are compatible with a higher stress sensitivity, or a decreased stress coping in those and is suggested to be involved with the onset of depression.

Binding of paroxetine to the serotonin transporter in membranes from different cells, subcellular fractions and species

The binding of [(3)H]-paroxetine to membrane serotonin transporter (SERT) has been studied in membranes from different sources and subcellular fractions. From rat were membranes from venous blood platelets, brain total cortex, brain microsomes, brain crude and purified synaptosomes. Membranes were obtained from venous blood platelets from human volunteers and from brain cortex tissue from neurosurgery (cerebral lobectomies following craniocerebral injuries). The main finding was that the K (D) of paroxetine binding to the SERT was the same for platelet and nerve ending (synaptosomal) membranes. That parameter was significantly lower in membranes from brain microsomes and cortex total tissue. No species related difference was found, where comparison was possible, between human and rat tissue. The equality of K (D) of paroxetine binding to blood platelet membranes and to membranes from nerve endings appears to encourage the use of such membranes as a model for brain SERT. Binding at two different temperatures for several of the fractions suggests that paroxetine-SERT interaction is entropy-driven.

Serotonergic candidate genes and puerperal psychosis: an association study

BACKGROUND

Altered serotonergic function is implicated in the aetiology and pathogenesis of a host of psychiatric disorders, and structural variations/polymorphisms in genes encoding the serotonin transporter and various serotonin receptor subtypes are attractive candidates to investigate the biological component underlying these disorders. Specific phenotypic subtypes, that perhaps represent homogeneous forms of the disorder, may increase the power to detect genes in complex diseases.

OBJECTIVE

We investigated regulatory and functional polymorphic DNA markers of serotonergic candidate genes using a case-control approach in puerperal psychosis and bipolar affective disorder probands.

METHODS

We genotyped 320 female participants (104 puerperal psychosis probands, 102 bipolar disorder participants and 114 controls) at the serotonin transporter SERT (5-HTT) 5-HTTVNTR and 5-HTTLPR locus; serotonin receptor 2A (5-HT2A)-T102C and His452Tyr loci, the serotonin receptor 2C (5-HT2C)-Cys23Ser locus, and seven unrelated Alu polymorphic markers.

RESULTS

We observed an association of the puerperal psychosis phenotype with the allele 10 of 5-HTTVNTR of SERT (P=0.004) and a modest association with the genotypic frequencies of the 5-HTTLPR (P=0.036). A nominal P value of 0.006 was observed with the S-10 haplotype in the PP group as compared with bipolar affective disorder probands. Significant association was observed with bipolar affective disorder phenotype with Tyr allele of the 5-HT2A His452Tyr gene polymorphism (P=0.00043) even after a conservative multiple test correction. No association was observed, however, with the 5-HT2A T102C locus, and the distribution of the other seven Alu markers did not differ between the groups.

CONCLUSION

The association between polymorphisms in serotonergic genes (SERT and 5-HT2A, 5-HT2C) suggests that these genetic factors can modulate vulnerability to puerperal psychosis in female bipolar participants.

Successful Treatment of Epilepsy with Serotonin Reuptake Inhibitors: Proposed Mechanism

The widely used antidepressants Specific Serotonin Reuptake Inhibitors (SSRI) have been tried with success as anticonvulsants in cases of nonsymptomatic epilepsy. This attempt was performed on the basis of experimental data suggesting the involvement of impairments of the serotonin system in the genesis of epilepsy. This overview summarizes the clinical data and presents biochemical and neurochemical evidences suggesting the mechanism of the therapeutic effects of SSRI in nonsymptomatic epilepsy. In particular, studies on blood-borne neutral amino acids and platelet serotonin transporter (SERT) in epileptics suggest: (a) That a decreased brain availability of tryptophan may be related to some types of epilepsy. (b) That reduction of the density of SERT may be a homeostatic reaction in the brain following epileptic seizures.

Human genetics and pharmacology of neurotransmitter transporters

Biogenic amine neurotransmitters are released from nerve terminals and activate pre- and postsynaptic receptors. Released neurotransmitters are sequestered by transporters into presynaptic neurons, a major mode of their inactivation in the brain. Genetic studies of human biogenic amine transporter genes, including the dopamine transporter (hDAT; SLC6A3), the serotonin transporter (hSERT; SLC6A4), and the norepinephrine transporter (hNET; SLC6A2) have provided insight into how genomic variations in these transporter genes influence pharmacology and brain physiology. Genetic variants can influence transporter function by various mechanisms, including substrate affinities, transport velocity, transporter expression levels (density), extracellular membrane expression, trafficking and turnover, and neurotransmitter release. It is increasingly apparent that genetic variants of monoamine transporters also contribute to individual differences in behavior and neuropsychiatric disorders. This chapter summarizes current knowledge of transporters with a focus on genomic variations, expression variations, pharmacology of protein variants, and known association with human diseases.

An overlooked connection: serotonergic mediation of estrogen-related physiology and pathology

BACKGROUND

In humans, serotonin has typically been investigated as a neurotransmitter. However, serotonin also functions as a hormone across animal phyla, including those lacking an organized central nervous system. This hormonal action allows serotonin to have physiological consequences in systems outside the central nervous system. Fluctuations in estrogen levels over the lifespan and during ovarian cycles cause predictable changes in serotonin systems in female mammals.

DISCUSSION

We hypothesize that some of the physiological effects attributed to estrogen may be a consequence of estrogen-related changes in serotonin efficacy and receptor distribution. Here, we integrate data from endocrinology, molecular biology, neuroscience, and epidemiology to propose that serotonin may mediate the effects of estrogen. In the central nervous system, estrogen influences pain transmission, headache, dizziness, nausea, and depression, all of which are known to be a consequence of serotonergic signaling. Outside of the central nervous system, estrogen produces changes in bone density, vascular function, and immune cell self-recognition and activation that are consistent with serotonin's effects. For breast cancer risk, our hypothesis predicts heretofore unexplained observations of the opposing effects of obesity pre- and post-menopause and the increase following treatment with hormone replacement therapy using medroxyprogesterone.

SUMMARY

Serotonergic mediation of estrogen has important clinical implications and warrants further evaluation.

The role of estrogen therapy in postpartum psychiatric disorders: an update

OBJECTIVES

The aim of this review is to assess and summarize the existing literature data about the efficacy of estrogen replacement therapy (ERT) in preventing and treating postpartum psychiatric disorders.

METHODS

An extensive and unrestrictive computerized search (from 1970 to June 2005) on MEDLINE/PubMed, TOXNET, EMBASE, and Cochrane Databases was conducted with the following search terms: estradiol, estrogen-treatment, hormonal treatment, therapy, postpartum depression, postnatal depression, puerperal depression, postpartum blues, postpartum psychosis, lactation, and breastfeeding.

RESULTS

In assessing available literature information about the role of ERT in preventing and treating puerperal psychiatric diseases, all reviewed studies were found to suffer from severe methodological limitations.

CONCLUSION

Well-designed and strictly focused multicenter trials are warranted in order to firmly establish the effectiveness of ERT in puerperal psychiatric disorders.

The neurobiology of postpartum depression

Postpartum psychiatric changes can range from maternity blues to psychosis. Causality is still undetermined, but explanations for these disturbances often focus on hormonal changes and dysregulation. Researchers have begun the process of delineating what neurobiological factors may be associated with depressive disorders in pregnancy and the postpartum. This article reviews the current literature on the roles of gonadal and pituitary hormones in the psychopathophysiology of postpartum mood disorders. Other biological factors, such as biogenic amines, neuroactive steroids, cholesterol, and fatty acids, are also discussed. The potential benefits of neuroimaging to aid in understanding neuropsychiatric changes that occur in the context of postpartum depression are also considered.