Maternal treatment with a selective delta-opioid receptor agonist during gestation has a sex-specific pro-cognitive action in offspring: mechanisms involved

Background: There is growing evidence that the treatment of several mental disorders can potentially benefit from activation of delta-opioid receptors. In the future, delta-agonists with a safe pharmacological profile can be used for the treatment of mood disorders in pregnant women. However, the data on prenatal exposure to delta-opioid agonists are missing. The present study is aimed to test the hypothesis that the activation of delta-opioid receptors during gravidity has positive effects on the behaviour accompanied by changes in glutamate and monoamine neurotransmission. Methods: Gestating Wistar rats were chronically treated with a selective delta-agonist SNC80 or vehicle. Adult male and female offspring underwent novel object recognition (for the assessment of cognition) and open field (for the assessment of anxiety and habituation) tests, followed by in vivo electrophysiological examination of the activity of hippocampal glutamate and midbrain serotonin (5-HT) and dopamine neurons. Results: We found that the maternal treatment with SNC80 did not affect the offspring's anxiety, habituation, and 5-HT neuronal firing activity. Female offspring of SNC80-treated dams exhibited improved novelty recognition associated with decreased firing rate and burst activity of glutamate and dopamine neurons. Conclusion: Maternal treatment with delta-opioid agonists during gestation may have a pro-cognitive effect on offspring without any negative effects on anxiety and habituation. The putative pro-cognitive effect might be mediated via mechanism(s) involving the firing activity of hippocampal glutamate and mesolimbic dopamine neurons.

Bridging the mood and stress hormone levels between mothers and their babies: The study design and first preliminary results

The neurobiological mechanisms involved in the influence of post-partum maternal mood fluctuations on child development are far from being understood. Here we present the design of an ongoing study aimed to test the hypothesis that the mental state of the mother has an impact on her neonate which is manifested by similarities in the neuroendocrine function of the mother and the child. The hypothesis is being tested under both stress and non-stress conditions in mothers and babies aged 3-4 days and 7-9 months. The focus will be given to correlations with maternal postpartum mood. To confirm the correctness of methodological approaches and the feasibility of the study several preliminary analyses were performed. Salivary alpha-amylase activity as a marker of sympathetic activation and cortisol as the effective hormone of the hypothalamic-pituitary-adrenocortical axis were measured. The obtained results showed the feasibility of saliva sampling in neonates using a sampling time of 120 s. The analysis of cortisol in hair revealed increased concentrations during the third trimester of pregnancy, which is consistent with the knowledge of high cortisol concentrations during pregnancy. A positive correlation was observed between salivary cortisol values before and after the stress test in mother-infant dyads at both the post-partum period and 7-9 months thereafter. Understanding the mechanisms involved in "the bridge" between the mother and her baby will help to develop necessary interventions directed to help mothers in the early postpartum period.

Neuroendocrine response to a psychosocial stress test is not related to schizotypy but cortisol elevation predicts inflexibility of semantic memory retrieval

An altered stress response can contribute to the transition from preclinical psychotic symptoms to the clinical manifestation of schizophrenia and other psychotic disorders. The present study was aimed at testing the hypotheses that (i) the autonomic and neuroendocrine responses under psychosocial stress are dysregulated in individuals with high psychosis proneness (schizotypy); (ii) the magnitude of post-stress autonomic activation and cortisol release predicts alterations in semantic memory retrieval. The study was performed in 73 healthy individuals of both sexes with either high or low schizotypal traits preselected out of 609 individuals using the Schizotypal Personality Questionnaire. A psychosocial stress procedure based on public speech was used as a stress model. We found that individuals with high schizotypy engaged in less adaptive emotional stress-coping strategies than low schizotypy individuals. Yet, the neuroendocrine, immune, and sympathetic activation in response to the stress test was not different between the groups. Irrespective of the exposure to the stressor, individuals with high schizotypy were less fluent when retrieving associations from semantic memory. In addition, we demonstrated that acute psychosocial stress reduced the flexibility of semantic memory retrieval. The post-stress mental inflexibility was reliably predicted by the concomitant elevation of cortisol concentrations in saliva. The present study thus brings novel evidence indicating that the acute psychosocial challenge impairs retrieval flexibility in the semantic domain, which may be due to neuroendocrine activation.

Effects of chronic delta-opioid receptor agonist on the excitability of hippocampal glutamate and brainstem monoamine neurons, anxiety, locomotion, and habituation in rats

BACKGROUND

Short-term treatment with non-peptide agonists of delta-opioid receptors, such as agonist SNC80, induced behavioral effects in rodents, which could be modulated via changes in central neurotransmission. The present experiments aimed at testing the hypothesis that chronic treatment with SNC80 induces anxiolytic effects associated with changes in hippocampal glutamate and brainstem monoamine pathways.

METHODS

Adult male Wistar rats were used in experiments. Rats were treated with SNC80 (3 mg/kg/day) for fourteen days. Neuronal excitability was assessed using extracellular in vivo single-unit electrophysiology. The behavioral parameters were examined using the elevated plus maze and open field tests.

RESULTS

Chronic SNC80 treatment increased the excitability of hippocampal glutamate and ventral tegmental area dopamine neurons and had no effect on the firing activity of dorsal raphe nucleus serotonin cells. Chronic SNC80 treatment induced anxiolytic effects, which were, however, confounded by increased locomotor activity clearly confirmed in an open field test. The ability to cope with stressful situations and habituation processes in a novel environment was not influenced by chronic treatment with SNC80.

CONCLUSION

Our study suggests that the psychoactive effects of SNC80 might be explained by its ability to stimulate hippocampal glutamate and mesolimbic dopamine transmission.

Testosterone but not cortisol concentrations in hair correlate between mothers and their prepubertal children under real-life stress conditions

The aim of the present study is to test the hypothesis that there is an association between the neuroendocrine state, reflected by testosterone and cortisol concentrations in hair, of the mother and her child under difficult real-life stress conditions (COVID-19 pandemic). The research sample consisted of 45 healthy mothers and their prepubertal children (7 - 11 years) of both sexes. The hair samples of mother-child dyads were collected twice to obtain cumulative stress hormone concentrations from April till the end of June and July till the end of September 2020. Thus, 90 mother-child pairs were analyzed. The results showed that both cortisol and testosterone concentrations were significantly higher in the hair of mothers compared to those in their children. The results of cortisol concentrations in hair do not support the hypothesis stated above. In line with our hypothesis are the results of hair testosterone measurements showing a positive correlation between testosterone concentrations in mothers and their children. With respect to the known relationship of testosterone with aggressive behavior, an important finding is that above-mentioned correlation was particularly strong in women with intense subjective feelings of anger in the investigated three months period. Women with strongly prevalent subjective feelings of sadness failed to show a significant correlation between hair cortisol concentrations in mothers and their children, in spite of the known relationship of cortisol to depressive mood. It may be suggested that chronic testosterone secretion reflects the association between the neuroendocrine function of the mother and her child under real-life stress conditions.

Salivary testosterone, testosterone/cortisol ratio and non-verbal behavior in stress

The relationship between hormone release and non-verbal communication under stress conditions is still not sufficiently explored. The aim of the present study was to test the hypothesis that salivary testosterone concentrations and testosterone/cortisol (T/C) ratios correlate positively with assertive behavior representing a non-aggressive form of dominance during an acute stress situation. As a stress model, a socially evaluated cold pressor test was investigated in healthy men. The non-verbal behavior was analyzed according to the ethological coding system for interviews described by Troisi (1999). Salivary testosterone concentrations did not change throughout the stress test. The T/C ratios decreased significantly over time only in subjects showing high stress perception. The duration of affiliative and the frequency of flight behavior was higher in subjects with high stress perception compared to those with low stress perception. A significant positive correlation between the duration of prosocial behavior and values of T/C ratios was found in the whole sample. The area under the curve values of testosterone positively correlated with the duration of assertive behavior in the group with high stress perception and negatively in the other group. Our findings allow suggesting that the changes in non-verbal behavior during acute psychosocial stress situations may be more pronounced in subjects showing high stress perception. Obtained results motivate further research on a better understanding of the consequences of the lack of sense of full facial expressions, such as wearing face masks, on the balance between hormones and non-verbal behavior under stress conditions.

Psychotropic Drug Effects on Steroid Stress Hormone Release and Possible Mechanisms Involved

There is no doubt that chronic stress accompanied by adrenocortical stress hormone release affects the development and treatment outcome of several mental disorders. Less attention has been paid to the effects of psychotropic drugs on adrenocortical steroids, particularly in clinical studies. This review focuses on the knowledge related to the possible modulation of cortisol and aldosterone secretion under non-stress and stress conditions by antipsychotic drugs, which are being used in the treatment of several psychotic and affective disorders. The molecular mechanisms by which antipsychotic drugs may influence steroid stress hormones include the modulation of central and/or adrenocortical dopamine and serotonin receptors, modulation of inflammatory cytokines, influence on regulatory mechanisms in the central part of the hypothalamic-pituitary axis, inhibition of corticotropin-releasing hormone gene promoters, influencing glucocorticoid receptor-mediated gene transcription, indirect effects via prolactin release, alteration of signaling pathways of glucocorticoid and mineralocorticoid actions. Clinical studies performed in healthy subjects, patients with psychosis, and patients with bipolar disorder suggest that single and repeated antipsychotic treatments either reduce cortisol concentrations or do not affect its secretion. A single and potentially long-term treatment with dopamine receptor antagonists, including antipsychotics, has a stimulatory action on aldosterone release.

Occupational burnout in oncologists in Kazakhstan

BACKGROUND

Although burnout levels in oncologists are likely high, its predictors remain poorly understood.

AIMS

This study was aimed to verify the prevalence of occupational burnout in oncology doctors and nurses in the major cancer centre in Kazakhstan and to elucidate its predictors to plan future prevention activities.

METHODS

In the leading tertiary-level cancer centre in Kazakhstan, we recruited 256 subjects (67% doctors and 33% nurses, 62% women, median age 37.5 [interquartile range 15] years) and offered them Maslach Burnout Inventory to quantify emotional exhaustion (EE), depersonalization (DP) and personal accomplishment (PA). Demographics, fatigue, health-related quality of life with SF-8 and lifestyle were tested as predictors of burnout in multivariate logistic regression models.

RESULTS

Number of subjects with high EE was 121 (47%), high DP was 161 (63%) and high PA was 152 (59%). Fatigue, worse mental component score (MCS), being single and not exercising regularly predicted more burnout in EE. Fatigue, worse physical component score (PCS) and worse MCS predicted more burnout in DP. Finally, more burnout in PA was independently associated with fatigue, worse PCS, being married or divorced and having a university or academic degree.

CONCLUSIONS

The prevalence of occupational burnout in oncologists was high, necessitating early burnout prevention programmes, addressing, among other, fatigue reduction and regular exercise.