José Balboa

Serotonin upregulates the activity of phagocytosis through 5-HT1A receptors

In this study, we investigated whether serotonin could regulate the in vitro activity of phagocytosis through 5‐hydroxytryptamine or serotonin (5‐HT1A) receptors. Mouse peritoneal macrophages were cultured with serotonin and the activity of phagocytosis was assessed by the uptake of zymosan and latex particles added to the culture media. Specific binding of [3H]8‐OH‐DPAT and immunohistochemistry using an affinity‐purified anti‐5‐HT1A‐receptor antibody were assayed in the macrophages. In addition, we took advantage of the availability of pharmacological inhibitors of nuclear factor‐κB (NF‐κB) to explore its role in the regulation of the 5‐HT1A receptor. Serotonin increased the in vitro activity of phagocytosis in a dose‐dependent manner. The 5‐HT1A receptor agonist (±)‐8‐hydroxy‐2‐(di‐n‐propyl‐amino)‐tetralin (R(+)‐8‐OH‐DPAT) reproduced these effects. Serotonin‐ or R(+)‐8‐OH‐DPAT‐induced increases in phagocytosis were blocked by the 5‐HT1A receptor antagonist WAY100635 and the NF‐κB inhibitor pyrrolidinedithiocarbamate. Moreover, mouse peritoneal macrophages expressed specific binding sites for [3H]8‐OH‐DPAT when cultivated in the presence of zymosan or latex beads. Immunohistochemistry confirmed the expression of the 5‐HT1A receptor protein in the macrophages. These results show that serotonin can upregulate the activity of peritoneal macrophages through 5‐HT1A receptors.

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 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 nefazodone on voluntary ethanol consumption induced by isolation stress in young and aged rats

Late-onset ethanol (EtOH) consumption is related to life and social stressors of aging. The stress system (hypothalamic-pituitary-adrenal, HPA, axis) coordinates the adaptive response of the organism to stressors, but age-related deficits in HPA function seem to be associated with disorders such as late-onset EtOH consumption, anxiety and depression. In the present study, we examined whether HPA dysfunction is associated with stress-related EtOH consumption in aged rats and whether the treatment with nefazodone hydrochloride, a phenylpiperazine antidepressant, partially reverses the adverse effects of isolation (ISOL) stress. The animals were offered two-bottle choice consumption of 0.2% saccharin and 10% EtOH/0.2% saccharin, and then exposed to 4 days of ISOL stress on an irregular, unpredictable schedule. ISOL stress-induced increases in corticosterone secretion and EtOH consumption both during and following the stress (recovery period) in aged rats. Nevertheless, this effect at the recovery period was not evident in young stressed rats. Nefazodone caused a significant decrease in plasma corticosterone levels and EtOH consumption. The attenuation of stress-induced corticosterone by nefazodone was correlated with reduced EtOH consumption. These findings link the effect of ISOL stress to the induction of voluntary EtOH consumption following the end of the stressor and the limitation of aged HPA to down-regulated corticosterone.

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.

Effects of resveratrol on expression of vascular endothelial growth factor in human gingival fibroblasts stimulated by periodontal pathogens

Abstract Objective. To investigate the effects of resveratrol, a naturally occurring polyphenol, on the expression of vascular endothelial growth factor (VEGF) in human gingival fibroblast culture in response to vesicles and outer membrane proteins from periodontopathic bacteria. Material and methods. Human gingival fibroblasts were stimulated with vesicles and outer membrane proteins from Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. In human gingival fibroblast cultures treated with or without resveratrol, VEGF production was evaluated by means of enzyme-linked immunosorbent assay and VEGF mRNA expression by means of reverse transcription polymerase chain reaction analysis. Vascular permeability enhancement was measured by the leakage of intravenously injected dye at the injection site of supernatant from cultures of human gingival fibroblasts stimulated by vesicles and outer membrane proteins. Results. Resveratrol significantly inhibited the increased production of VEGF by human gingival fibroblasts in response to vesicles and outer membrane proteins from periodontopathic bacteria, as shown by the detection of these proteins and their mRNA in vitro. Moreover, resveratrol treatment significantly decreased vascular permeability enhancement induced by supernatant from human gingival fibroblast cultures stimulated by vesicles and outer membrane proteins. Conclusions. Overall, these findings suggest that resveratrol inhibits production of VEGF by stimulated human gingival fibroblasts and can inhibit vascular permeability, suggesting a therapeutic role for it in pathogenic bacteria-induced periodontal inflammation.

Administration of the 5-hydroxytryptamine(1A) receptor antagonist WAY100635 suppresses acute experimental allergic encephalomyelitis in Lewis rats.

Experimental allergic encephalomyelitis (EAE) is a T-cell inflammatory disease of the central nervous system (CNS) widely considered as an animal model of multiple sclerosis. In Lewis rats, myelin basic protein-complete Freunds adjuvant (MBP-CFA)-induced EAE is an acute monophasic disease from which animals recover fully. In our experiments, daily treatment (since day 1 after MBP-CFA inoculation) with the 5-hydroxytryptamine((1A)) (5-HT(1A)) receptor agonist (R)-(+)-8-hydroxy-2-(Dipropylamino)-tetralin (R(+)-8-OH-DPAT) resulted in a dose-related enhancement of neurological and histological signs in EAE-induced rats. This effect of R(+)-8-OH-DPAT was reduced by the co-administration of the 5-HT(1A) receptor antagonist (N-[2-(4-[2-mehoxyphenil]-1-piperazinyl)-ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY100635) at the peak of the acute disease. Moreover, treatment with WAY100635 since inoculation resulted in a delayed onset of the first clinical signs, milder disease and earlier regression of neurological signs along with a decrease in inflammation in the CNS.

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 nefazodone on the development of experimentally induced tumors in stressed rodents

RationaleAnxiety and depression are commonly encountered in patients with cancer and constitute risk and prognostic factors for the disease. Although previous findings do not support an overall association between the use of antidepressants and higher prevalence of cancer, results for serotonin uptake inhibitors are not entirely reassuring.ObjectivesWe evaluated the effects of nefazodone, a serotonin and norepinephrine (NE) reuptake inhibitor and 5-HT2A receptor antagonist antidepressant, on the appearance of breast cancer induced by mammary tumor virus (MTV) in mice, and on the development of lung metastases in rats injected intravenously with Walker 256 (W-256) carcinosarcoma cells.MethodsFemale C3H/He mice carrying the MTV were monitored for mammary tumor incidence and latent periods while being treated with a daily intraperitoneal injection with placebo or nefazodone. Rats were administered 104 W-256 cells, exposed to a chronic auditory stressor for 8 days, and then killed to evaluate metastatic nodules in the lungs.ResultsAlthough all of the mice were potential candidates for MTV-induced breast cancer, those treated with nefazodone were partially protected against adverse effects of stress induced by the daily administration of placebo on both parameters. Relative to placebo, nefazodone reduced the stress-induced increase in the number and percentage area of metastases in the frontal section through pulmonary hilus and increased the survival periods of rats given W-256 cells and exposed to a chronic auditory stressor.ConclusionsOur results provide evidence of the beneficial effects of nefazodone against the adverse effects of stress on tumor development and metastaticity in rodents, but did not show significant effects in unstressed rodents.

Effects of Psychological Stress and Fluoxetine on Development of Oral Candidiasis in Rats

ABSTRACT Psychological stress has been found to suppress cell-mediated immune responses that are important for limiting the proliferation of Candida albicans. Fluoxetine has been observed to reduce negative consequences of stress on the immune system in experimental and clinical models, but there are no data on its effects on oral candidiasis. We designed experiments to evaluate the effects of fluoxetine on the development of oral candidiasis in Sprague-Dawley rats exposed to a chronic auditory stressor. Animals were submitted to surgical hyposalivation in order to facilitate the establishment and persistence of C. albicans infection. Stress application and treatment with drugs (placebo or fluoxetine) were initiated 7 days before C. albicans inoculation and lasted until the end of the experiments, on day 15 postinoculation. Establishment of C. albicans infection was evaluated on days 2 and 15 after inoculation. Tissue injury was determined by the quantification of the number and type (normal or abnormal) of papillae on the dorsal tongue per microscopic field. A semiquantitative scale was devised to assess the degree of colonization of the epithelium by fungal hyphae. Our results showed that stress exacerbates C. albicans infection in the tongues of rats. Significant increases in Candida counts, the percentage of the tongues surface covered with clinical lesions, the percentage of abnormal papillae, and the colonization of the epithelium by hyphae were found in stressed rats compared to the nonstressed ones. Treatment with fluoxetine significantly reversed these adverse effects of stress. Besides the psychopharmacological properties of fluoxetine against stress, it has consequences for Candida infection.