Interaction of prenatal stress and morphine alters prolactin and seizure in rat pups

Prenatal stress and increased susceptibility to anxiety-like behaviors: role of neuroinflammation and balance between GABAergic and glutamatergic transmission

Neuroplasticity during the prenatal period allows neurons to regenerate anatomically and functionally for re-programming the brain development. During this critical period of fetal programming, the fetus phenotype can change in accordance with environmental stimuli such as stress exposure. Prenatal stress (PS) can exert important effects on brain development and result in permanent alterations with long-lasting consequences on the physiology and behavior of the offspring later in life. Neuroinflammation, as well as GABAergic and glutamatergic dysfunctions, has been implicated as potential mediators of behavioral consequences of PS. Hyperexcitation, due to enhanced excitatory transmission or reduced inhibitory transmission, can promote anxiety. Alterations of the GABAergic and/or glutamatergic signaling during fetal development lead to a severe excitatory/inhibitory imbalance in neuronal circuits, a condition that may account for PS-precipitated anxiety-like behaviors. This review summarizes experimental evidence linking PS to an elevated risk to anxiety-like behaviors and interprets the role of the neuroinflammation and alterations of the brain GABAergic and glutamatergic transmission in this phenomenon. We hypothesize this is an imbalance in GABAergic and glutamatergic circuits (as a direct or indirect consequence of neuroinflammation), which at least partially contributes to PS-precipitated anxiety-like behaviors and primes the brain to be vulnerable to anxiety disorders. Therefore, pharmacological interventions with anti-inflammatory activities and with regulatory effects on the excitatory/inhibitory balance can be attributed to the novel therapeutic target for anxiety disorders.

Stress during pregnancy affected neonatal outcomes and changed cortisol and leptin levels both in mothers and newborns

BACKGROUND

The present study aimed to determine the effect of perceived stress during pregnancy on neonatal outcomes and cortisol and leptin levels in mothers and their newborns.

METHODS

This longitudinal study was carried out on 110 pregnant women in Miandoab city, Iran. Mothers, who had singleton pregnancies and gestational age of 24 to 28 weeks, were included in the study. The participants were asked to fill out Cohen's Perceived Stress Scale (PSS). The mothers were then tracked in gestational ages of 28-32 weeks, 32-36 weeks, and the time of delivery. The maternal and umbilical cord blood samples were obtained during labor in order to measure leptin and cortisol levels.

RESULTS

Umbilical cortisol level was significantly higher in newborns who had meconium stained amniotic fluid than those who did not. Maternal blood leptin levels at delivery were significantly higher in the mothers whose neonates had respiratory distress, low birth weight, low head circumference, low Apgar score, and were premature than those whose neonates did not have such problems. The level of leptin in umbilical cord blood was significantly higher in neonates who had respiratory distress than those who did not. The results also showed a significant correlation between maternal cortisol levels and PSS during weeks 24-28 and the entire pregnancy. A significant relationship was observed between umbilical leptin and maternal leptin levels.

CONCLUSIONS

It can be concluded that stress during pregnancy is accompanied by fetal distress. The probable reason for newborns distress may be related to increased maternal leptin levels.

In Up to My Ears and Temporal Lobes: Effects of Early Life Stress on Epilepsy Development

Epilepsy and stress are each significant concerns in today's society, bearing heavy impacts on mental and physical health and overall quality of life. Unfortunately, the intersection between these is potentially even more concerning, as stress is a frequent trigger of seizures and may contribute to neural hyperexcitability. A growing body of research suggests a connection between early life stress (occurring in the prenatal or postnatal stage) and later development of epilepsy. While the larger part of this literature suggests that early life stress increases vulnerability for epilepsy development, there are a number of interacting factors influencing this relationship. These factors include developmental stage at which both stressor and seizure assessment occur, type of stressor, sex effects, and type of seizure (convulsive or non-convulsive). Additionally, a number of potential mechanisms have been identified, including activation of the hypothalamic-pituitary-adrenal axis, neuroinflammation, altered inhibitory/excitatory balance, and temporal lobe structures. Developing a clearer understanding of this relationship between early life stress and epilepsy, the factors that influence it, and underlying mechanisms that may serve as targets for intervention is crucial to improving quality of life for persons with epilepsy.

Long-time effects of prenatal morphine, tramadol, methadone, and buprenorphine exposure on seizure and anxiety in immature rats

Purpose: This study aimed to investigate seizures and anxiety-like behaviors in immature rats prenatally exposed to opiate drugs.Materials and methods: Pregnant rats were randomly divided into five groups: saline, morphine, tramadol, methadone, and buprenorphine. Administrations were performed intraperitoneally once a day for the last seven days of pregnancy. Neonatal rats were subdivided into ten groups, split according to sex. Anxiety-like behavior was tested on postnatal day (PD) 19. On PD 20, seizure was induced by PTZ injection.Results: Morphine in male rats had an increased time to onset (p < 0.005), whereas there was a decreased number of tonic-clonic seizures in females (p < 0.05). Tramadol had an increased duration of tonic-clonic seizures compared to morphine and methadone in males (p < 0.005). Moreover, tramadol decreased open arm time and locomotor activity in males more than in females (p < 0.05). Methadone decreased open arm time in males (p < 0.05). Furthermore, buprenorphine and tramadol decreased open arm entrance in male rats (p < 0.05).Conclusions: It was demonstrated that prenatal tramadol significantly increases both the duration of seizures and anxiety-like behaviors in immature male rats, whereas morphine decreases both of them. The effects of tramadol on seizure and anxiety-like behavior may be due to the comorbid occurrence of the symptoms of these two disorders.

Parental pre-conception stress status and risk for anxiety in rat offspring: specific and sex-dependent maternal and paternal effects

Prenatal stressful events have long-lasting consequences on behavioral responses of offspring. While the effects of gestational and maternal stress have been extensively studied on psychological alterations in the progeny, little is known about effects of each parent's pre-conception life events on emotional responses in offspring. Here, the effect of maternal and/or paternal pre-conception stress was investigated on anxiogenic responses of offspring. Male and female adult rats were subjected to predatory stress (contactless exposure to a cat for 1 + 1 h per day) for 50 (male, n: 12) and 15 (female, n: 24) consecutive days; controls were not exposed. After the stress procedure, the control and stressed rats were mated to create four types of breeding pairs: control female/control male, stressed female/control male, control female/stressed male, and stressed female/stressed male. On postnatal days 30-31, the offspring were tested on the elevated plus maze and plasma corticosterone concentration was measured. Half of the pups were exposed to acute predatory stress before the elevated plus maze test. In most subgroups, corticosterone and anxiety-like behaviors in the offspring with both or only one parent exposed to pre-gestational stress increased compared to their control counterparts. However, under acute stress conditions, a different sex-dependent pattern of anxiety responses emerged. The combined effects of maternal and paternal stress were not additive. Hence, individual offspring behaviors can be influenced by the former life stress experiences of either parent. Incorporation of genetic and epigenetic aspects in development of neurobehavioral abnormalities and reprograming of the hypothalamic-pituitary-adrenal axis may contribute to this phenomenon. Lay summary Early life stress (including during pregnancy) is known to have long-lasting effects on offspring, including emotional behaviors. Whether individual anxiety behaviors can be influenced by stress experiences of each parent even before a pregnancy is less well-understood. Our findings from this study on rats exposed to predator stress before mating suggest that maternal or paternal adult life events prior to pregnancy can lead to maladaptive behavior in their offspring later in life.

Prenatal stress and elevated seizure susceptibility: Molecular inheritable changes

Stressful episodes are common during early-life and may have a wide range of negative effects on both physical and mental status of the offspring. In addition to various neurobehavioral complications induced by prenatal stress (PS), seizure is a common complication with no fully explained cause. In this study, the association between PS and seizure susceptibility was reviewed focusing on sex differences and various underlying mechanisms. The role of drugs in the initiation of seizure and the effects of PS on the nervous system that prone the brain for seizure, especially the hypothalamic-pituitary-adrenal (HPA) axis, are also discussed in detail by reviewing the papers studying the effect of PS on glutamatergic, gamma-aminobutyric acid (GABA)ergic, and adrenergic systems in the context of seizure and epilepsy. Finally, epigenetic changes in epilepsy are described, and the underlying mechanisms of this change are expanded. As the effects of PS may be life-lasting, it is possible to prevent future psychiatric and behavioral disorders including epilepsy by preventing avoidable PS risk factors.

Acute and chronic effects of morphine on Low-Mg2+ ACSF-induced epileptiform activity during infancy in mice hippocampal slices

Interaction of morphine and seizure is complex. Mouse brain hippocampal slices were used to estimate how acute and chronic morphine treatment alters the low-magnesium artificial cerebrospinal fluid (LM-ACSF)-induced seizure activity. Hippocampal slices were taken from the normal and morphine-treated mice. The normal mice received saline while the other group (morphine-treated mice) received morphine daily for 5 consecutive days. Saline/morphine administration was performed subcutaneously (s.c, 0.1 mL) at postnatal days 14-18. Hippocampal slices of all animals were perfused with LM-ACSF followed by different morphine concentrations (0, 10, 100, and 1000 μM) or naloxone (10 μM). Changes in the spike count were considered as indices for quantifying the seizure activity in the slices. In hippocampus of both groups perfused with 10 or 1000 μM morphine, epileptiform activity was suppressed while it was potentiated at 100 μM morphine. The excitatory effect of morphine at 100 μM was stronger in normal mice (acute exposure) than in dependent mice (chronic exposure). Naloxone suppressed the epileptiform activities in both groups. Suppressive effect of naloxone was more significant in morphine-treated mice than in normal mice. The seizure activity in morphine-dependent mice was more labile than that of normal mice. It can be concluded that morphine had a biphasic effect on LM-ACSF-induced epileptiform activities in both groups. The occurrence of seizure was comparable in acute and chronic exposure of morphine but strength of the effect was considerably robust in normal mice. The down regulation of opioid receptors in chronic exposure is likely to be responsible for these differences.

Effect of early-life inflammation and magnesium sulfate on hyperthermia-induced seizures in infant rats: Susceptibility to pentylenetetrazol-induced seizures later in life

This study investigated the effect of inflammation and MgSO₄ pretreatment on behaviors caused by hyperthermia (HT) and the effect of these interventions on PTZ-induced seizure a week later. In this experimental study, rat pups experienced inflammation on postnatal day 10 (P10). On P18-19, the pups received either saline or MgSO₄ then subjected to hyperthermia. On P25-26, PTZ-induced seizure was initiated in the rats. Neonatal inflammation increased the susceptibility to HT-induced seizure. Inflammation and HT increased the susceptibility to PTZ-induced seizure. Pretreatment with MgSO₄ before hyperthermia decreased the susceptibility to both HT- and PTZ-induced seizure. Furthermore, calcium and magnesium blood levels significantly decreased compared to control rats. It can be concluded that neonatal inflammation potentiates while pretreatment with MgSO₄ attenuates HT-induced seizures. Also, neonatal inflammation and HT potentiate PTZ-induced seizure initiated one week later.

Modeling prenatal opioid exposure in animals: Current findings and future directions

The past decade has seen a drastic rise in the number of infants exposed to opioids in utero. It is unclear what lasting effect this exposure may have on these children. Animal models of prenatal opioid exposure may provide insight into potential areas of vulnerability. The present review summarizes the findings across animal models of prenatal opioid exposure, including exposure to morphine, methadone, buprenorphine, and oxycodone. Details regarding the drug, doses, and duration of treatment, as well as key findings, are summarized in tables with associated references. Finally, significant gaps in the current preclinical literature and future directions are discussed.

Effect of prenatal stress on ɑ5 GABAA receptor subunit gene expression in hippocampus and pilocarpine induced seizure in rats

The GABAergic synapses go through structural and functional maturation during early brain development. Maternal stress alters GABAergic synapses in developing brain, which are associated with the pathophysiology of neuropsychiatric disorders in adults. The present study aimed to investigate the effect of prenatal restraint stress (PS) on pilocarpine-induced seizure and ɑ5 subunit of γ-amino butyric acid type A (GABA_A) receptor expression in hippocampus. Pregnant Wistar rats were subjected to PS at gestational days 15-17 and the pups were examined for susceptibility to seizure and ɑ5 subunit of GABA_A receptor expression in hippocampus at postnatal days 14 and 21 (P14 and PND 21). Quantitative real-time PCR was used for evaluating the gene expression in the pups. Pilocarpine was injected intraperitoneally into the pups and seizure behaviors were recorded. The results showed that ɑ5 subunit mRNA expression significantly increased in hippocampus at both the P14 and P21 in the stressed rats. However, ɑ5 subunit level was greater at the P21 than at the P14 in both the groups. Latency of first tonic-clonic seizure significantly decreased in the PS group compared to the control pups. Number and duration of tonic-clonic seizures increased in the PS rats compared to the controls. PS led to an increase in total score of seizure at the P14 and P21. It can be concluded that PS increases the seizure susceptibility and GABA_A receptor ɑ5 subunit gene expression in offspring; it is likely that the mechanism of increased seizure susceptibility by PS, at least in part, can increase the GABA_A receptor ɑ5 subunit gene expression in hippocampus.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Pregestational stress attenuated fertility rate in dams and increased seizure susceptibility in offspring

Many studies have found that stress during pregnancy is linked to an increased incidence of epileptic behaviors and reproductive disorders. However, few works have investigated the effect of pregestational stress on seizure susceptibility in the offspring. We investigated the effect of pregestational stress on epileptic behaviors in the offspring as well as fertility rate in dams. The male and female rats were randomly divided into four groups to form a combination of control and stressed groups for each sex. The rats were subjected to predatory stress (exposed to a cat) twice per day for 50 (male) and 15 (female) consecutive days. At the end of the stress procedure, the rats were coupled as follows: both male and female control (M_C-F_C), male stressed/female control (M_S-F_C), male control/female stressed (M_C-F_S), and both male and female stressed (M_S-F_S). Then, the puppies born from these groups were counted and evaluated for pentylentetrazole (PTZ)-induced seizure. There was no significant difference between the male and female pups in each identical group in terms of litter size and epileptic behaviors, except duration of tail rigidity and duration of immobility. The total score of seizure increased in all the stressed groups, but more severely in the M_S-F_S group. However, the onset of the first epileptic behavior and tonic-clonic seizure significantly decreased in the stressed groups. Moreover, fertility rate significantly decreased in the stressed groups compared with the control group, but there was no significant difference in terms of litter size between the groups. These data revealed the impact of pregestational stress during spermatogenesis and oogenesis on fertility rate in dams and epileptic behaviors in the offspring.

Association of Serum Prolactin Concentrations with Renal Failure in Diabetic Patients

Background and aims: Diabetes is one of the causes of end-stage renal disease, so that about 70% of all diabetic patients have nephropathy. Prolactin is a hormone that is affected by diabetes but the interaction between diabetes and prolactin has not been understood properly. This study aimed to evaluate the relationship between changes in serum prolactin levels in diabetic patients with renal failure.

Material and methods: In this study 223 individuals were participated and after assessment of inclusion/exclusion criteria 189 individuals were evaluated. Finally, the individuals were divided into three groups: Control (C), Diabetic (D), and Diabetic Nephropathy (DN). Blood samples were collected between 8.00 a.m. and 12.00 a.m. for measurement of prolactin levels and biochemical analysis.

Results: The results showed that sodium, potassium, urea, creatinine and prolactin significantly increased in DN group compared to control individuals (P< 0.001). The prolactin levels were significantly decreased in the group of patients with diabetes (P< 0.001).

Conclusion: The results of the current study indicated that serum prolactin level decreased in diabetes while it increased in diabetic nephropathy.

Prenatal stress potentiates febrile seizure and leads to long-lasting increase in cortisol blood levels in children under 2years old

Neurological disorders can be exacerbated in an offspring that is exposed to stress prenatally. This study is aimed to investigate the severity of febrile seizures (FS) in the offspring under 2years old that were prenatally stressed. In this study, 158 children below 2years old with FS were selected. Information about convulsion including seizure lasting, recurrence of seizure, age of the first seizure and type of FS was gathered. Blood samples were obtained from the offspring to measure the cortisol blood levels. Questionnaire was filled in to evaluate the perceived stress and exposure or non-exposure to major stresses during pregnancy. Results of this study showed that both high Perceived Stress Scores (PSS) during pregnancy and exposure to major stresses during pregnancy significantly increased seizure duration and seizure intensity. Also, the appearance of complex FS was significantly higher in prenatally stressed children than the unexposed ones. Further, cortisol blood levels were significantly higher in prenatally stressed subjects. It can be concluded that both higher PSS and/or exposure to major stresses during pregnancy potentiate FS parameters and lead to long lasting increase in cortisol blood levels in the offspring.

Psychological stress has a higher rate of developing addictive behaviors compared to physical stress in rat offspring

Prenatal stress could have great influence on development of offspring and might alter cognitive function and other physiological processes of children. The current study was conducted to study the effect of physical or psychological prenatal stress on addictive and anxiety-like behavior of male and female offspring during their adolescence period (postnatal day (PND) 40). Adult female rats were exposed to physical (swimming) or psychological (observing another female rat swimming) stress from day six of gestation for 10 days. Male and female offspring were assayed for anxiety-like behavior, motor and balance function and morphine conditioned place preference using the open field, elevated plus maze (EPM), rotarod and wire grip assay and conditioned place preference. Offspring in both physical and psychological prenatal stress groups demonstrated significant increase in anxiety-like behavior in EPM paradigm, but no alterations were observed in motor and balance function of animals. Offspring in the psychological prenatal stress group had an increased preference for morphine in comparison to control and physical prenatal stress groups. Results of the current study demonstrated that animals exposed to psychological stress during fetal development are at a higher risk of developing addictive behaviors. Further research might elucidate the exact mechanisms involved to provide better preventive and therapeutic interventions.

Effect of prenatal restraint stress and morphine co-administration on plasma vasopressin concentration and anxiety behaviors in adult rat offspring

Stressful events and exposure to opiates during gestation have important effects on the later mental health of the offspring. Anxiety is among the most common mental disorders. The present study aimed to identify effects of prenatal restraint stress and morphine co-administration on plasma vasopressin concentration (PVC) and anxiety behaviors in rats. Pregnant rats were divided into four groups (n = 6, each): saline, morphine, stress + saline and stress + morphine treatment. The stress procedure consisted of restraint twice per day, two hours per session, for three consecutive days starting on day 15 of pregnancy. Rats in the saline and morphine groups received either 0.9% saline or morphine intraperitoneally on the same days. In the morphine/saline + stress groups, rats were exposed to restraint stress and received either morphine or saline intraperitoneally. All offspring were tested in an elevated plus maze (EPM) on postnatal day 90 (n = 6, each sex), and anxiety behaviors of each rat were recorded. Finally, blood samples were collected to determine PVC. Prenatal morphine exposure reduced anxiety-like behaviors. Co-administration of prenatal stress and morphine increased locomotor activity (LA) and PVC. PVC was significantly lower in female offspring of the morphine and morphine + stress groups compared with males in the same group, but the opposite was seen in the saline + stress group. These data emphasize the impact of prenatal stress and morphine on fetal neuroendocrine development, with long-term changes in anxiety-like behaviors and vasopressin secretion. These changes are sex specific, indicating differential impact of prenatal stress and morphine on fetal neuroendocrine system development. Lay Summary Pregnant women are sometimes exposed to stressful and painful conditions which may lead to poor outcomes for offspring. Opiates may provide pain and stress relief to these mothers. In this study, we used an experimental model of maternal exposure to stress and morphine in pregnant rats. The findings indicated that maternal stress increased anxiety in offspring while morphine decreased such effects, but had negative effects on the levels of a hormone controlling blood pressure, and activity of offspring. Hence morphine should not be used in pregnancy for pain and stress relief.