Effects of buspirone on the immune response to stress in mice

Assessing the Anti-Inflammatory Activity of the Anxiolytic Drug Buspirone Using CRISPR-Cas9 Gene Editing in LPS-Stimulated BV-2 Microglial Cells

Buspirone is an anxiolytic drug with robust serotonin receptor 1A (Htr1a) agonist activities. However, evidence has demonstrated that this drug also targets the dopamine D3 receptor (Drd3), where it acts as a potent antagonist. In vivo, Drd3 blockade is neuroprotective and reduces inflammation in models of Parkinson’s disease. To test if buspirone also elicited anti-inflammatory activities in vitro, we generated stable Drd3^−/− and Htr1a^−/− BV2 microglial cell lines using CRISPR-Cas9 technology and then tested the effects of buspirone after lipopolysaccharide (LPS) challenge. We found that LPS exposure had no effect on cell viability, except in Htr1a^−/− cells, where viability was reduced (p < 0.001). Drug treatment reduced viability in Drd3^−/− cells, but not in WT or Htr1a^−/− cells. Buspirone counteracted LPS-induced NO release, NOS2, IL-1β and TNF-α gene expression in WT cells, whereas it exerted limited effects in Drd3^−/− or Htr1a^−/− microglia. In summary, our findings indicate that buspirone attenuates microglial polarization after LPS challenge. These results also highlight some major effects of Drd3 or Htr1a genetic ablation on microglial biology, raising important questions on the complex role of neurotransmitters in regulating microglia functions.

Inflammatory and immunological changes caused by noise exposure: A systematic review

Today, due to the growth of industries and spread of the use of various instruments and devices that produce high noise levels, it is necessary to pay more attention to the effects of exposure to noise on organs and tissues in the body. The importance of the immune system in fighting external and pathogenic factors has raised the need to consider external factors (such as harmful physical factors) and make efforts to avoid producing them. In this systematic review, 811 potentially relevant studies were found in Google Scholar, PubMed, and Web of Science databases, of which 32 different English-written articles were included in the study. The method of searching and systematically reviewing articles was based on the assessment tool of the multiple systematic reviews (AMSTAR) method. The results of this study suggested that noise could affect the function of the immune system and its components by affecting other systems and organs of the body, including the central nervous system, auditory system, circulatory system, and endocrine gland. Moreover, it can be hypothesized that noise affects immune system by producing the NADPH oxidase (Nox) and reactive oxygen species (ROS).

Empirically Supported Use of Psychiatric Medications in Adolescents and Adults with IBD

BACKGROUND

The use of psychotropic medications, particularly antidepressants, is common in patients with inflammatory bowel disease (IBD) in spite of a lack of their robust efficacy in this population. This review provides an overview of the use trends of different classes of antidepressant and anti-anxiety medication and their effects on mood, nervous system function, gastrointestinal physiology and immunity drawing from the literature available in the general population, other medical conditions, and when available, patients with IBD. It also covers the evidence base for the actions, efficacy, and potential complications of antidepressants organized by different classes.

METHODS

We conducted a PubMed search of articles relating the different drug classes probed to the terms above in different populations of interest. All types of articles were accepted including case reports and series, open and randomized trials, reviews, and expert opinion. We also examined the reference lists of the publications found.

RESULTS

Selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) are the most commonly prescribed agents for anxiety and depression in patients with IBD, though their efficacy for these conditions in the general population are mild to moderate at best. SSRIs are generally well tolerated, though at higher doses, they, like most antidepressant classes, can be associated with activation, serotonergic syndrome, and increased suicidal ideation. TCAs have many more serious side effects but have some shown efficacy for functional GI symptoms. A newer class, the serotonin noradrenergic reuptake inhibitors (SNRIs), can be effective for refractory depression, anxiety and chronic pain syndromes with a side effect profile similar to both SSRIs and more mild manifestations of TCAs. Mirtazapine has moderate efficacy for depression if sedation and weight gain side effects are tolerated and some small support for use in nausea and vomiting. Bupropion targets dopamine and noradrenaline reuptake and has moderate efficacy for depression, and some small support for use in fatigue and smoking cessation. Buspirone has an indication for generalized anxiety disorder though studies show only a minimal benefit. It has some growing evidence for use in functional dyspepsia. Most of these agents have physiological effects on the brain, immune system, and gastrointestinal tract (with the exception of bupropion) hence their therapeutic and side effects manifested in these systems.

CONCLUSION

Antidepressant medications are frequently prescribed for depression, anxiety disorders, and chronic pain syndromes, but overall support for their efficacy is modest at best. Psychological interventions have growing support for having much more robust effects without the side effects of antidepressants and should be considered first-line treatment or at least an adjunct to psychotropic medications for these conditions.

Effects of fluoxetine on cellular immune response in stressed mice

We studied the effects of fluoxetine, a non-tricyclic antidepressant drug that selectively inhibits re-uptake of serotonin by presinaptic neurons in the brain, on cellular immune responses in mice exposed to a chronic auditory stressor. The natural killer (NK) cell activity was reduced after 4, 8, 12, 16 and 20 days of stress exposure with a partial recovery on days 16 and 20. Daily treatment with fluoxetine partially reversed these adverse effects of stress in a dose-dependent manner. Significant differences appeared when fluoxetine was administered at 2 mg/kg and maximum effect was reached at doses of 5 mg/kg. The capacity of T cells to generate cytotoxic T-lymphocytes (CTL) in mixed lymphocyte cultures and in vivo was reduced after 4 days of stress application and this effect was partially reduced when mice were injected with 5 mg/kg of fluoxetine. Nevertheless, in our experiments, fluoxetine did not significantly affect the cellular immunity in unstressed mice. In conclusion, fluoxetine seems to partially recover the adverse effects of chronic stress on cellular immune response.

Effects of fluoxetine on the activity of phagocytosis in stressed mice

We studied the effects of 1, 2, 5, 10 and 20 mg/kg of fluoxetine on the activity of phagocytosis in mice subjected to a chronic auditory stressor. Both the in vitro and in vivo activity of phagocytosis, measured using the zymosan-particle uptake method and the carbon clearance test, respectively, were reduced after 2, 4, 8 and 16 days of stress exposure. A partial recovery on the in vivo activity of phagocytosis was found on day 16th. Daily treatment with fluoxetine partially reversed the adverse effects of stress in a dose-dependent manner on both parameters but did not significantly affect the activity of phagocytosis in unstressed mice. Significant differences appeared when fluoxetine was administered at 2 mg/kg. Maximum effect was reached at 5 mg/kg.

Music, immunity and cancer

The effects of music on the immune system and cancer development were evaluated in rodents subjected to sound stress. Animals were exposed daily to broad band noise around midnight and/or music for 5 hours on the following morning. Thymus and spleen cellularity, peripheral T lymphocyte population, the proliferative response of spleen cells to mitogen concanavalin A and natural killer cell activity were calculated in BALB/c mice. Sprague Dawley rats were injected i.v. with Walker 256 carcinosarcoma cells; 8 days later the rats were sacrificed and the number of metastatic nodules on the surface of the lungs was calculated macroscopically. Music reduced the suppressive effects of stress on immune parameters in mice and decreased the enhancing effects of stress on the development of lung metastases provoked by carcinosarcoma cells. Music enhanced the immune parameters and the anti-tumor response in unstressed rodents. Our data at present demonstrates that music can effectively reverse adverse effects of stress on the number and capacities of lymphocytes that are required for an optimal immunological response against cancer in rodents.

Effects of nefazodone on the immune system of mice

Mice exposed to a chronic auditory stressor and treated with nefazodone (10 mg/kg/day s.c.), showed a reduction in stress-induced suppression of thymus and spleen cellularity, and in peripheral T-Iymphocyte population. The in vitro blastogenic response of spleen lymphoid cells to mitogen concanavalin A, the in vitro and in vivo activity of phagocytosis, both measured using the zymosan and carbon clearance tests, respectively, were also assessed and nefazodone was found to partially reverse the inhibitory effect of stress on those parameters. Nefazodone did not significantly affect those parameters in unstressed mice. In conclusion, this report provides evidence on the immunoprotective effects of this novel antidepressant drug against the adverse effects of stress in mice.

Effects of fluoxetine on the development of lung metastases induced by operative stress in rats

Experiments were performed in order to evaluate the effects of fluoxetine, a selective inhibitor of neural serotonin transporter antidepressant, on the development lung metastases in rats subjected to laparotomy and injected (i.v.) with 10(4) Walker 256 (W-256) carcinosarcoma cells. The number of metastatic nodules on the surface of the lungs, as well as the percentage-area of metastases in the frontal section through pulmonary hilus were increased in rats subjected to sham-surgery or laparotomy. Treatment with fluoxetine (5 mg/kg) partially reversed those adverse effects of surgery, but the difference was clearer when it was administered before surgery was performed. Survival periods were also assessed and fluoxetine was found to decrease the lethality of rats exposed to surgery.

Effects of fluoxetine on the immunosuppressive response to stress in mice

Mice exposed to a chronic auditory stressor and treated with fluoxetine (5 mg/kg) showed a reduction in stress-induced suppression of thymus and spleen cellularity, and in peripheral T lymphocyte population. The blastogenic response of spleen lymphoid cells and the delayed type hypersensitivity response (DTH) to sheep red blood cells (SRBC) were also assessed and fluoxetine was found to partially reverse the inhibitory effect of stress on both parameters.

Tryptophan availability and the susceptibility to stress in multiple sclerosis: a hypothesis

In his seminal description of the clinical manifestations of multiple sclerosis (MS) in 1868 Charcot suggested that psychological stress is an important factor in the pathogenesis of the disease. MS patients often relate that mental stress exacerbates their symptoms and even provokes attacks of their disease. Moreover, a subgroup of MS patients experiences exacerbation of symptoms following a period of mental stress rather than occurring at times when stress is maximal, i.e., attacks are reported to occur on the rebound from stress. Psychological stress may also contribute to the onset and long term clinical deterioration of the disease. Mental stress is associated with activation of the hypothalamic-pituitary adrenal (HPA) axis resulting in increased release of ACTH and cortisol secretion. Stress-induced activation of the HPA axis is associated with an increased metabolism of cerebral serotonin (5-HT) the synthesis of which is dependent upon the availability of its precursor tryptophan. Thus, increased tryptophan availability may partly underlie the general response to stress. Plasma and CSF tryptophan levels are diminished in chronic MS patients and it is suggested that plasma tryptophan levels are even lower in patients who are stressed. Attenuated increase in the availability of systemic tryptophan in response to stress is thought to underlie the susceptibility of MS patients to stress. This hypothesis is supported by the findings in chronic MS patients of a significantly diminished adrenal cortisol reactivity to insulin-induced hypoglycemia which is considered a stress response mediated through the 5-HT system. Consequently, since patients with MS exhibit an abnormal response to stress it follows that increased tryptophan availability through dietary supplementation would diminish their vulnerability to psychological stress. Additionally, if sustained or repeated stress contributes to progression and clinical deterioration of the disease then chronic tryptophan supplementation also may halt its progression.