Influence of conceptus presence and preovulatory estradiol exposure on uterine gene transcripts and proteins around maternal recognition of pregnancy in beef cattle.

The uterine environment must provide sufficient endocrine conditions and nutrients for pregnancy maintenance and conceptus survival. The objective of this study was to determine the effects of preovulatory estradiol and conceptus presence on uterine transcripts and uterine luminal fluid (ULF) proteins. Beef cows/heifers were synchronized and artificially inseminated (d 0). Uteri were flushed (d 16); conceptuses and endometrial biopsies were collected. Total cellular RNA was extracted from endometrium for RNA sequencing and RT-PCR validation. There were two independent ULF pools made for each of the following groups: highE2/conceptus, highE2/noconceptus, lowE2/conceptus, and lowE2/noconceptus that were analyzed using the 2D LC-MS/MS based iTRAQ method. There were 64 differentially expressed genes (DEGs) and 77 differentially expressed proteins (DEPs) in common among the highE2/conceptus vs highE2/noconceptus and lowE2/conceptus vs lowE2/noconceptus groups. In summary, the interaction between preovulatory estradiol and the conceptus induces the expression of genes, proteins, and pathways necessary for pregnancy.

Stress and behavioural responses to winter shearing differ between pregnant and non-pregnant ewes.

High progesterone concentrations reduce the stress responses in several mammals. Therefore, it may be expected that pregnant ewes have lower responses to stressors than anoestrous ewes. Our aims were to compare the stress response and the behavioural changes of pregnant and non-pregnant ewes sheared during winter. Two trials were with 20 were pregnant (group PR) and 17 non-pregnant ewes (group NP). In the first trial blood samples were collected immediately before and during the first 180 min after shearing, and cortisol, total protein, and albumin concentrations were measured, and globulin concentrations were calculated. In the second trial, the frequency in which each ewe was observed standing, lying down, walking and grazing were recorded from Day -3 to Day -1 (Day 0 = shearing), from Day 1 to Day 5, on Days 13 and 20-21 during 8 h/day. Scan observations were done every 10 min from 8:00 h to 12:00 h and from 14:00 h to 18:00 h (total = 50 recordings.day). Non-pregnant ewes had greater cortisol concentrations than PR ewes (P = .007). Non-pregnant ewes also had greater total protein concentrations than PR ewes (P = .029). Albumin concentration tended to be greater in NP than PR ewes (P = .064). Globulin concentration 30 min after shearing was greater in PR than in NP ewes (P = .047). Pregnant ewes were observed more frequently standing than NP ewes (P = .013). Non-pregnant ewes were observed more frequently lying down and walking than PR ewes (P = .039 and P = .009, respectively). Before shearing, on Day 2 and Day 4, NP ewes walked more frequently than P ewes (P = .007, P < .0001, P = .007 respectively). Pregnant ewes were observed grazing more frequently than NP ewes (P = .009). Pregnant ewes grazed more than NP ewes on Days 1 and 5 (P = .005 and P < .0001 respectively). Overall, we concluded that shearing was a strong stressor that provoked sustained changes in the behavioural pattern, physiological status and gregariousness intensity despite being or not pregnant. Some responses, as cortisol concentration, changes in the time walking and grazing and the decrease of the cohesiveness after shearing seem to be less pronounced in pregnant than in non-pregnant ewes.

Sex-Related Effects of Prenatal Stress on Region-Specific Expression of Monoamine Oxidase A and β Adrenergic Receptors in Rat Hearts / Efeitos Sexo-Específicos de Estresse Pré-Natal na Expressão Região-Específica de Monoamina Oxidase A e Receptores Adrenérgicos Β no Coração de Ratos

Abstract Background: Prenatal stress may increase risk of developing cardiovascular disorders in adulthood. The cardiotoxic effects of catecholamines are mediated via prolonged adrenergic receptor stimulation and increased oxidative stress upon their degradation by monoamine oxidase A (MAO-A). Objectives: We investigated long-term effects of prenatal stress on β (1, 2, 3) adrenergic receptors and MAO-A gene expression in the hearts of adult rat offspring. Methods: Pregnant rats were exposed to unpredictable mild stress during the third week of gestation. RNA was isolated from left ventricular apex and base of adult offspring. Quantitative PCR was used to measure gene expression in collected ventricular tissue samples. The level of significance was set to p < 0.05. Results: β3 adrenergic receptor mRNA was undetectable in rat left ventricle. β1 adrenergic receptor was the predominantly expressed subtype at the apical and basal left ventricular myocardium in the control females. Male offspring from unstressed mothers displayed higher apical cardiac β1 than β2 adrenergic receptor mRNA levels. However, β1 and β2 adrenergic receptor mRNAs were similarly expressed at the ventricular basal myocardium in males. Unlike males, prenatally stressed females exhibited decreased β1 adrenergic receptor mRNA expression at the apical myocardium. Prenatal stress did not affect cardiac MAO-A gene expression. Conclusions: Collectively, our results show that prenatal stress may have exerted region- and sex-specific β1 and β2 adrenergic receptor expression patterns within the left ventricle.

Resumo Fundamento: Estresse pré-natal pode aumentar os riscos de desenvolver doenças cardiovasculares na idade adulta. Os efeitos cardiotóxicos de catecolaminas são mediados pela estimulação prolongada dos receptores adrenérgicos e pelo aumento do estresse oxidativo após sua degradação pela monoamina oxidase A (MAO-A). Objetivos: Investigamos os efeitos a longo prazo de estresse pré-natal nos receptores β (1, 2, 3) adrenérgicos e na expressão do gene MAO-A nos corações da prole adulta de ratos. Método: Ratas prenhes foram expostas a estresse crônico moderado imprevisível durante a terceira semana de gestação. O RNA foi isolado do ápice e da base do ventrículo esquerdo da prole adulta. Utilizou-se PCR quantitativa em tempo real para medir a expressão gênica nas amostras de tecido ventricular coletadas. O nível de significância foi estabelecido em p < 0,05. Resultados: Foi indetectável o mRNA do receptor adrenérgico β3 no ventrículo esquerdo dos ratos. O receptor adrenérgico β1 foi o subtipo mais expresso no miocárdio ventricular esquerdo apical e basal nas fêmeas controle. A prole masculina das mães não estressadas apresentou níveis cardíacos apicais de mRNA do receptor adrenérgico β1 mais altos do que os de β2. Porém, mRNAs dos receptores adrenérgicos β1 e β2 foram expressos de forma semelhante no miocárdio basal ventricular na prole masculina em geral. Ao contrário da prole masculina, a prole feminina exposta ao estresse pré-natal exibiu uma expressão diminuída do mRNA do receptor adrenérgico β1 no miocárdio apical. O estresse pré-natal não afetou a expressão gênica de MAO-A cardíaca. Conclusões: Coletivamente, nossos resultados mostram que estresse pré-natal pode ter exercido padrões de expressão região- e sexo-específica dos receptores adrenérgicos β1 e β2 no ventrículo esquerdo.

Maternal prenatal stress in rats influences c-fos expression in the spinal cord of the offspring.

Previous studies in humans have reported a link between maternal stress and disturbed infant physiological behavior. The objective of our study was to examine in experimental rats how maternal prenatal stress induced by a forced swim test affects offspring afferent spinal responses mediated by stimulation of vaginocervical receptors. The activation of spinal cord neurons showing c-fos expression was examined following vaginocervical mechanical stimulation in adult rats, which were the offspring of dams exposed to gestational stress from E10 until delivery. Vaginocervical stimulation of both prenatal-stressed and non-prenatal-stressed rats induced an increase in immunoreactive protein in the spinal cord ranging from T12 to S1 segmental levels. However, a significantly higher (40%) increase in the expression of Fos-immunoreactive neurons was observed in vaginocervical stimulated prenatally stressed rats than in non-stimulated prenatally stressed ones. This increase was higher in L5-S1 levels than in T12-L4. When the regional distribution was examined, results showed that up to 80% of activated neurons were located in the dorsal horn in both non-stimulated prenatally stressed and stimulated prenatally stressed groups, with a significantly higher density in the latter. Our results demonstrate that maternal prenatal stress can have consequences on vaginocervical responses conveyed to the spinal cord. The increase in Fos labeled neurons in T12-S1 in prenatally stressed rats induced by vaginocervical stimulation suggests the hypersensitivity of the genital tract associated with activation of spinal circuits spanning multiple segments.

Keeping oxytocin neurons under control during stress in pregnancy.

Oxytocin synthesised by magnocellular neurons in the supraoptic and paraventricular nuclei plays an important role in mammalian parturition. Accordingly, in late pregnant rats, oxytocin neurons are restrained from premature activation and stimulated oxytocin secretion is inhibited, preserving the expanded neurohypophysial oxytocin stores for parturition. A wide range of stressors stimulate oxytocin secretion in the rat. Some physical stressors, in particular immune challenge with systemic interleukin-1beta (IL-1beta, a cytokine that mimics infection) signal to magnocellular oxytocin neurons via brainstem noradrenergic neurons. Afferents relaying information from the uterus and birth canal also converge onto brainstem noradrenergic neurons and are robustly activated at parturition. Thus, quiescence of these inputs may be important in minimising the risk of preterm labour. Focussing on an immune challenge model (since infection is a major cause of preterm labour in women), we have found that the responsiveness of oxytocin neurons to IL-1beta is markedly suppressed in late pregnancy. Here we discuss the mechanisms involved, which include induction of central inhibitory opioid tone by the progesterone neurosteroid metabolite, allopregnanolone, and act to prevent activation of oxytocin neurons by inappropriate stimuli at the end of pregnancy.

Role of pregnancy and parturition in induction of maternal behavior in prairie voles (Microtus ochrogaster).

In prairie voles (Microtus ochrogaster), most virgin females are infanticidal. To determine the onset of maternal responsiveness, female prairie voles were tested for maternal behavior as virgins and at different times throughout pregnancy. Female voles that were infanticidal as virgins by and large remained infanticidal throughout pregnancy. In contrast, about 30% of voles that were maternal as virgins became infanticidal during pregnancy. To test whether events associated with parturition facilitate the onset of maternal behavior, females had their litters delivered by Caesarean section within a day of expected delivery or were allowed to give birth naturally with sham surgery occurring shortly before or after birth. Females that gave birth naturally were fully maternal and did not attack unrelated pups, but females subjected to artificial delivery remained infanticidal. This suggests that events closely related to parturition are crucial for full development of maternal behavior in female prairie voles.

Novel males' capacity to disrupt early pregnancy in mice (Mus musculus) is attenuated via a chronic reduction of males' urinary 17beta-estradiol.

Mature male mice of proven fertility were administered chronic oral doses of anastrozole, a potent aromatase inhibitor, and also given a low-phytoestrogen diet. Urine was taken non-invasively from such males and from untreated control males and assayed for 17beta-estradiol and testosterone via ELISA procedures. After 8 weeks of drug or vehicle administration, urinary 17beta-estradiol declined to significantly lower levels in anastrozole-treated males than in non-treated males, whereas testosterone levels were comparable in the two groups. Inseminated females were exposed to drug-treated, vehicle-treated, or no males during days 1-6 of gestation, around intrauterine implantation of fertilized ova. Females exposed to vehicle-treated males produced fewer litters than did those kept in isolation. Females exposed to anastrozole-treated males produced significantly more litters than did those exposed to vehicle-treated males. These data support the notion that male excretions of estrogens may in part mediate novel-male-induced pregnancy disruptions, although other influences of aromatization on behaviour and metabolism remain possibilities.

Pregnancy is associated with low fear reactions in ewes.

The aims of the study were: (1) to test the influence of pregnancy on responses of ewes to several fear-eliciting situations, (2) to compare the first and latest stages of pregnancy, and (3) to investigate possible correlations between fear reactions and progesterone levels. Fear reactions of nonpregnant (NP; N=22) and pregnant (P) Ile-de-France ewes (day 40 of pregnancy: N=43; day 140 of pregnancy: N=19) were compared during three situations classically reported to induce fear in sheep: isolation, surprise, and the presence of a human. P ewes displayed significantly lower fear reactions than NP ewes when isolated and when confronted with a surprise effect combined with the appearance of a novel object. This reduction in fearfulness may be mediated principally through reduced fear of isolation. However, fear of a human remained constant despite pregnancy. Fear reactions of ewes tested during isolation on gestation day 40 or 140 did not differ, suggesting that decreased fear is not restricted to the latest stage of pregnancy. A negative correlation was found between plasma progesterone levels and fear during isolation and surprise tests of ewes with low levels of progesterone. The decrease in fearfulness during pregnancy may have some adaptative value for the survival of the young.

Antidepressant-like effects of pregnancy and progesterone in Wistar rats as measured in the differential reinforcement of the low-rate 72 s task.

RATIONALE: In rats, several behavioral changes occurring during pregnancy could be due to the presence of progesterone; some of them may be analyzed in the differential reinforcement of the low-rate 72 s task (DRL-72 s), which is designed for testing the antidepressant profile of drugs. OBJECTIVES: The aim of the present study was to analyze the behavior of pregnant rats or ovariectomized rats receiving exogenous progesterone in the DRL-72 s task. HYPOTHESIS: During pregnancy, rats will obtain a high number of reinforcers in the DRL-72 s task. METHODS: Pregnant rats or rats after delivery were tested in the DRL-72 s task at the 3rd, 7th, 14th, 17th, and 20th days. Control rats previously trained in the DRL-72 s task were ovariectomized; after recuperation, they received saline (0.9%, i.p.), clomipramine (1.25 mg/kg, i.p.), or desipramine (2.14 mg/kg, i.p.) for 28 days, and they were tested in the DRL-72 s task. In a second series of experiments, ovariectomized rats received vehicle or progesterone (0.5, 1.0, 2.0, 4.0 mg/kg, s.c.), and they were submitted to the DRL-72 s task. Locomotion was evaluated in the open field test. RESULTS: Pregnant rats tested at the 14th and 17th day and ovariectomized rats receiving progesterone or two tricyclic antidepressants obtained a higher number of reinforcers and a cohesive rightward shift in inter-response time distributions than those rats evaluated after delivery in the DRL-72 s task. A lower locomotion was observed only at the end of pregnancy. CONCLUSIONS: Antidepressant-like effects of pregnancy and progesterone were found in Wistar rats as measured in the DRL-72 s task.

Hormones and behavior in rhesus macaque abusive and nonabusive mothers. 1. Social interactions during late pregnancy and early lactation.

This study investigated changes in hormone levels and social behavior during late pregnancy and early lactation in rhesus macaque abusive and nonabusive mothers. All subjects lived in large social groups in outdoor corrals. Estradiol and progesterone levels increased to a peak the week before parturition, dropped after parturition, and remained low thereafter. The hormonal profiles of abusive and nonabusive mothers were generally similar. There were few changes in social interactions involving contact, grooming, or aggression across pregnancy or lactation, and minor differences between abusive and nonabusive mothers. The transition to motherhood was accompanied by a reduction in active grooming and an increase in aggression, and such changes were more marked for abusive than nonabusive mothers. Some individual differences in social behavior were correlated with hormone levels during pregnancy, but not lactation. These findings suggest that although the endocrine changes underlying the periparturitional period may affect female social behavior, some of the social changes associated with motherhood are likely to reflect the presence of infants.

Maternal responsiveness increases during pregnancy and after estrogen treatment in macaques.

Maternal responsiveness in primates has long been considered emancipated from endocrine factors and entirely dependent on experience and cognition. Here we report that group-living pigtail macaque females increased their rate of interaction with infants in the last weeks of pregnancy in correspondence with an increase in plasma levels of estradiol and progesterone. Estrogen treatment increased the rate at which ovariectomized rhesus females interacted with infants. This is the first evidence that steroid hormones influence maternal responsiveness in anthropoid primates. All untreated ovariectomized females and nonpregnant females interacted with infants, indicating that although estrogen can enhance responsiveness to infants, ovarian or pregnancy hormones are not necessary for the expression of infant-directed behavior in female macaques. The findings of this study suggest fundamental similarities, rather than differences, in the endocrine modulation of maternal responsiveness in primates and other mammals.

Psychobiology of maternal behavior: contribution to the clinical understanding of maternal behavior among humans.

Psychobiological studies of maternal behavior among non-primate mammals have arrived at several general conclusions that may aid in our understanding of human maternal behavior and in the clinical treatment of parenting disorders. The hormonal basis of maternal behavior arises during pregnancy and consists of a hormonal priming phase, extending over most of pregnancy, and a hormonal triggering phase at the end of pregnancy. Hormonal priming in several species depends upon estrogen, progesterone and prolactin, and hormonal triggering depends upon a decline in progesterone and an increase in estrogen, prolactin and oxytocin in different species. The onset of maternal behavior is hormonally based but postpartum maternal behavior in several species is based upon the stimulation that the mother receives from her young (i.e. is non-hormonally based). There is a transition period between these two phases soon after parturition during which contact with the young plays a crucial role in the maintenance of maternal behavior. The onset of maternal behavior may be viewed as the resolution of conflict between approach and withdrawal responses of females to their offspring.

Changes in experimental anxiety during pregnancy and lactation.

The animals' reactivity and the levels of experimental anxiety during pregnancy and lactation in female rats were studied using the burying behavior test. The three main parameters analyzed in this test were: the cumulative burying behavior, the burying behavior latency, and the number of shocks necessary for displaying the behavior. The burying behavior was studied at the 7th, 14th, and 21st days of pregnancy and lactation. An additional group tested 12 h after parturition was also included. Simultaneously, in all animals, the ambulatory behavior was evaluated. All results were compared with those obtained in a control group of ovariectomized females. At the end of pregnancy a clear increase in burying behavior latency accompanied by a decrease in cumulative burying behavior was observed. Similarly, a clear reduction in burying behavior immediately after parturition was found. The number of shocks necessary for displaying the burying behavior were not modified along pregnancy and lactation with the exception of a clear decrease for the 7th lactation day. Changes in locomotor activity were observed at pregnancy, but not along lactation. These changes do not account for the reduction in burying behavior observed at the 14th gestation day. Data related to the reduction in burying behavior observed during gestation are discussed on the possible participation of progestins, while those found during lactation are discussed on the bases of the variations in serotonin and beta-endorphins that normally occur during this period.