Modulating Stress Susceptibility and Resilience: Insights from miRNA Manipulation and Neural Mechanisms in Mice

This study explored the impact of microRNAs, specifically mmu-miR-1a-3p and mmu-miR-155-5p, on stress susceptibility and resilience in mice of different strains. Previous research had established that C57BL/6J mice were stress-susceptible, while NET-KO and SWR/J mice displayed stress resilience. These strains also exhibited variations in the serum levels of mmu-miR-1a-3p and mmu-miR-155-5p. To investigate this further, we administered antagonistic sequences (Antagomirs) targeting these microRNAs to C57/BL/6J mice and their analogs (Agomirs) to NET-KO and SWR/J mice via intracerebroventricular (i.c.v) injection. The impact of this treatment was assessed using the forced swim test. The results showed that the stress-susceptible C57/BL/6J mice could be transformed into a stress-resilient phenotype through infusion of Antagomirs. Conversely, stress-resilient mice displayed altered behavior when treated with Ago-mmu-miR-1a-3p. The study also examined the expression of mmu-miR-1a-3p in various brain regions, revealing that changes in its expression in the cerebellum (CER) were associated with the stress response. In vitro experiments with the Neuro2a cell line indicated that the Antago/Ago-miR-1a-3p and Antago/Ago-miR-155-5p treatments affected mRNAs encoding genes related to cAMP and Ca2+ signaling, diacylglycerol kinases, and phosphodiesterases. The expression changes of genes such as Dgkq, Bdnf, Ntrk2, and Pde4b in the mouse cerebellum suggested a link between cerebellar function, synaptic plasticity, and the differential stress responses observed in susceptible and resilient mice. In summary, this research highlights the role of mmu-miR-1a-3p and mmu-miR-155-5p in regulating stress susceptibility and resilience in mice and suggests a connection between these microRNAs, cerebellar function, and synaptic plasticity in the context of stress response.

Effect of clozapine on ketamine-induced deficits in attentional set shift task in mice

RATIONALE

Clozapine (CLZ) is an effective treatment for schizophrenia, producing improvements in both negative symptoms and cognitive impairments. Cognitive impairments can be modelled in animals by ketamine (KET) and assessed using the attentional set-shift task (ASST).

OBJECTIVE

Our first aim was to determine whether CLZ improves cognitive function and reverses KET-induced cognitive impairments using the ASST. Our second aim was to assess dose dependency of these effects.

RESULTS

Our findings demonstrate that acute as well as sub-chronic administration of KET cause cognitive deficits observed as increase in number of trails and errors to reach the criterion in the EDS phase. CLZ 0.3 mg/kg reversed the effects of both acute and sub-chronic KET, with no effects on locomotor activity. However, clozapine's effect after sub-chronic administration of dose 0.3 mg/kg was not as explicit as in the case of acute treatment. Moreover, administration of 1 mg/kg CLZ to KET-treated mice induced or enhanced deficits in the extra-dimensional shift phase compared to 1 mg/kg CLZ administration to mice not receiving KET. Locomotor activity test showed sedation effects of CLZ 1 mg/kg after acute treatment; therefore, effect of CLZ 1 mg/kg on KET-induced cognitive deficits was not evaluated in the attentional set-shift task (ASST) test.

CONCLUSIONS

The present findings support dose-dependent effects of CLZ to reverse KET-induced cognitive deficits. The observed dose dependency may be mediated by activation of different receptors, including monomers and/or heterodimers.

Basal prolactin levels in rat plasma correlates with response to antidepressant treatment in animal model of depression

Prolactin (PRL) has been shown to be altered by psychotropic drugs, including antidepressant drugs (ADs). Many studies have focused on the response to antidepressant treatment (especially related to the serotonergic system) using the fenfluramine test (PRF), however some data suggest lack of correlation between PRF and prediction of clinical response to ADs. In our study we have investigated the hypothesis that basal plasma level of prolactin is a better predictor of antidepressant treatment. We have used Chronic Mild Stress (CMS) - the animal model of depression. Rats are exposed to CMS in combination with imipramine (IMI) treatment for 5 consecutive weeks. Blood samples were collected from the rat tail vein three times: before the CMS procedure, after 2 weeks of stress and after the complete CMS procedure (after 5 weeks of stress and IMI treatment). The PRL level in plasma was determined using the commercially available ELISA kit. In CMS, anhedonia in rats is manifested by reduced consumption of sucrose solution while administration of antidepressant drugs reverses anhedonia. Some animals (ca.30%) did not respond to antidepressant therapy and were considered treatment-resistant. There was no correlation between basal PRL levels and stress response, however, from the results obtained by Spearman Rank Correlation analysis we have observed a significant negative correlation between basal PRL levels before the CMS procedure and behavioral response to IMI administration. The obtained results indicate that the basal PRL level in rat plasma correlates with a good response to treatment in the animal model of depression.

Chronic mild stress alters the somatostatin receptors in the rat brain

RATIONALE

The involvement of somatostatin (SST) and its receptors in the pathophysiology of depression and stress has been evidenced by numerous studies.

OBJECTIVES

The purpose of the present study was to find whether chronic mild stress (CMS), an animal model of depression, affects the SST receptors in the rat brain and pituitary, as well as the level of SST in plasma.

METHODS

In CMS model, rats were subjected to 2 weeks of stress and behaviorally characterized using the sucrose consumption test into differently reacting groups based on their response to stress, i.e., stress-reactive (anhedonic), stress-non-reactive (resilient), and invert-reactive rats (characterized by excessive sucrose intake). We measured specific binding of [125I]Tyr3-Octreotide, expression of mRNA encoding sst2R receptors in the rat brains, expression of SST and its receptors in rat pituitary, and the level of SST in the plasma.

RESULTS

The obtained results show decreases in binding of [125I]Tyr3-Octreotide in most of rat brain regions upon CMS and no significant differences between three stressed groups of animals, except for significant up-regulation of sst2 receptor in medial habenula (MHb) in the stress-reactive group. In the same group of animals, significant increase in plasma SST level was observed.

CONCLUSIONS

There are two particularly sensitive sites distinguishing the response to stress in CMS model. In the brain, it is MHb, while on the periphery this predictor is SST level in plasma. These changes may broaden an understanding of the mechanisms involved in the stress response and point to the intriguing role of MHb.

Stathmin reduction and cytoskeleton rearrangement in rat nucleus accumbens in response to clozapine and risperidone treatment - Comparative proteomic study

The complex network of anatomical connections of the nucleus accumbens (NAc) makes it an interface responsible for the selection and integration of cognitive and affective information to modulate appetitive or aversively motivated behaviour. There is evidence for NAc dysfunction in schizophrenia. NAc also seems to be important for antipsychotic drug action, but the biochemical characteristics of drug-induced alterations within NAc remain incompletely characterized. In this study, a comprehensive proteomic analysis was performed to describe the differences in the mechanisms of action of clozapine (CLO) and risperidone (RIS) in the rat NAc. Both antipsychotics influenced the level of microtubule-regulating proteins, i.e., stathmin, and proteins of the collapsin response mediator protein family (CRMPs), and only CLO affected NAD-dependent protein deacetylase sirtuin-2 and septin 6. Both antipsychotics induced changes in levels of other cytoskeleton-related proteins. CLO exclusively up-regulated proteins involved in neuroprotection, such as glutathione synthetase, heat-shock 70-kDa protein 8 and mitochondrial heat-shock protein 75. RIS tuned cell function by changing the pattern of post-translational modifications of some proteins: it down-regulated the phosphorylated forms of stathmin and dopamine and the cyclic AMP-regulated phosphoprotein (DARPP-32) isoform but up-regulated cyclin-dependent kinase 5 (Cdk5). RIS modulated the level and phosphorylation state of synaptic proteins: synapsin-2, synaptotagmin-1 and adaptor-related protein-2 (AP-2) complex.

The effect of combined treatment with imipramine and amantadine on the behavioral reactivity of central ??1-adrenergic system in rats

The problem of drug-resistant depression implies a strong need for alternative antidepressant therapies. Recently, it has been shown that joint administration of a tricyclic antidepressant, imipramine (IMI), with amantadine (AMA), a drug already approved for clinical use in the treatment of other diseases, induces a stronger 'antidepressant' effect in the forced swimming test in rats than treatment with either drug given separately. Combined treatment with IMI and AMA also induces up-regulation of dopamine D2 and D3 receptors in the rat brain, and appears to be effective in the treatment of patients with drug-resistant unipolar depression. In the present study, we examined the effect of IMI (5 or 10 mg/kg p.o.) and AMA (10 mg/kg p.o.) given separately or jointly, either as a single dose or repeatedly (twice daily for 14 days) on the development of adaptive changes in the behavioral reactivity of the central alpha1-adrenergic system. Following repeated administration of the higher dose of IMI together with AMA, we observed an increase in clonidine-induced aggression in mice, and significant enhancement of D-amphetamine-induced locomotor hyperactivity, as well as phenylephrine-induced exploratory behavior, in rats. In binding studies using [3H]prazosin, no changes in the density (Bmax) or affinity (Kd) of alpha1-adrenergic receptors were observed in rat brain cortex. However, competition analysis allowed us to observe an increase in the affinity of alpha1-adrenergic receptors (Ki) for an agonist (phenylephrine) upon repeated treatment with IMI, given alone or in combination with AMA. AMA appears to act through several pharmacological mechanisms, none of which has been identified as the chief mode of action. In the light of data obtained in the present study, one can supplement the postulated mechanisms of antidepressant action of AMA by adaptive changes in the reactivity of alpha1-adrenergic receptors, which develop upon repeated combined treatment with IMI.

[The effect of health care reform in Germany on the pharmacist's role in pharmacotherapy]

The present paper describes the pharmacist's role in Germany during the health-service reform and shows his prospects within pharmacological therapy and his role in contemporary modern society. However, emphasis is placed on the out-patient provision of drugs. The development of the recent years clearly indicates the effects of the health-service reform on all concerned in German health services. For this reason the present paper has been extended to include the description of the current social and health guidelines for health services. Moreover, it also describes the individual stages of the health-service reform in Germany between 1989 and 1997. The theoretical part was supported by patient's opinion polls. With examples of 500 interviewees from Bavaria and Baden-Württemberg, patient habits were surveyed regarding drug consumption, compliance, self-treatment, and drug information as well as the patient's expectations of the pharmacist. Depending on the growth of scientific knowledge in health services and on the need for medical care, the pharmacist's role has to undergo continuous changes, worldwide. Due to the analysis and scrutiny of the transformation of German health services--for Germany has a state health insurance in traditional solidarity--the present paper gives a prediction concerning further development, and, above all, the necessary changes in the pharmacist's work in the framework of health services to be carried out. Generally it is possible to say that the obtained knowledge has general validity which other countries can make use of while considering their local conditions.

[Social pharmacy in pharmacy education]

Social pharmacy as the only pharmaceutical interdisciplinary field deals in its full scope with the problems of pharmacy und medicines in society. The paper presents the definition of the field and the scope of problems concerned both in teaching and research. The development in the Czech Republic and further prospects of the field in the education of pharmacists in the Czech Republic with regard to the current trends in the world are discussed.

[The past and the future of the Czech Pharmaceutical Society]

The main features of development of the Pharmaceutical Society as the only scientific, specialist and professional organization in the years 1950-1990 are surveyed. Increasing activities of the Society, extenvicity of the arranged actions and increasing interest of pharmacists to participate are stressed. Attention is drawn to the regular changes in the activity of the Society in the present time which result from the establishment and activity of the Pharmaceutical Chamber and the need to intensity the trade union movement. The Czech Pharmaceutical Society must continue tu guarantee the scientific standard of Czech pharmacy and appropriate foreign co-operation. Pharmacists working in the individual pharmaceutical sciences should assume positions in the management of the Society and its journal.

[Prognostic study of utilization of infusion preparations]

On the basis of an analysis of time series of consumption of infusion solutions in the Czech Republic its prognosis was made till the year 2000 using the trend analysis method. The results have shown that a further increase in consumption of infusion solutions must be expected. The forecasted consumption in the year 2000 with 90% reliability will reach the volume of 5.2 to 5.6 million litres. The production capacity for infusion solutions in the individual branches of Czech pharmacy will have to be adjusted to this trend.

[Drugs and health awareness in the population]

The authors made surveys of the health consciousness of groups of junior (20-30 years) and senior (above 60 years) citizens in the CSR. The use of medical services was significantly higher in the older persons. Complete satisfaction with the standard and availability of medical care was recorded only in 25% junior and 60% senior respondents. 22% of the respondents, mainly the younger ones, provide their own treatment. As to drugs which are available without prescription, analgesics are required most, followed by medicines used in case of a cold or cough. Women buy drugs and medicines more frequently than men. Expenditure on drugs varies between 5 and 50 Kcs per month. Drugs prescribed by doctors are taken by 84% of the junior and 87% of the senior patients. It is of interest that 69% of the respondents report that they keep left over drugs, while 31% of the patients discard them. From the investigation it is obvious that there are major shortcomings in the knowledge, attitudes and action of the population in relation to drugs. It is important to increase in this respect health educational efforts, but also the cooperation of doctors, pharmacists and patients to improve pharmacotherapy.

[Drug utilization of selected pharmacotherapeutic groups]

A single orientational survey investigated the consumption of antiepileptic, antihypertensive and vasodilating agents. The analysis aimed to investigate the effect of the factors of sex and age patients as to the requirements for drugs of the selected pharmacotherapeutic groups. Evaluation of the results was performed on the basis of statistical processing by means of the test of the difference of two relative values. A dependence of drug consumption on the above-mentioned identification characteristics was confirmed, high consumption of antihypertensive and vasodilating agents, particularly in higher age categories, was demonstrated. The results have shown that it is necessary for our health service to continue considering the growing trend of drug consumption and not only to record, but also to analyze the consumption and its assortment and to use the conclusions both in practice and theory of pharmacotherapy.

[Problems in forecasting and its practical application in pharmacy and monitoring drug utilization]

The authors discuss problems of prognoses and their possible application in the health services, in particular in pharmacy and in prediction of drug consumption. The authors summarize the results of some investigations made along these lines. They emphasize the importance of prognostic activities from the aspect of organization and control as well as from the aspect of perspective plans.