Participation of the Serotonergic System and Brain-Derived Neurotrophic Factor in the Antidepressant-like Effect of Flavonoids.

Depressive disorders are among the most disabling diseases experienced around the world, and their incidence has significantly increased over the last few decades due to multiple environmental, social, and biological factors. The search for new pharmacological alternatives to treat depression is a global priority. In preclinical research, molecules obtained from plants, such as flavonoids, have shown promising antidepressant-like properties through several mechanisms of action that have not been fully elucidated, including crossing of the blood brain barrier (BBB). This review will focus on discussing the main findings related to the participation of the serotonergic system and brain-derived neurotrophic factor (BDNF) on the antidepressant-like effect of some flavonoids reported by behavioral, neurochemical, and molecular studies. In this sense, evidence shows that depressive individuals have low levels of serotonin and BDNF, while flavonoids can reverse it. Finally, the elucidation of the mechanism used by flavonoids to modulate serotonin and BDNF will contribute to our understanding of the neurobiological bases underlying the antidepressant-like effects produced by these natural compounds.

Zebrafish as a Useful Tool in the Research of Natural Products With Potential Anxiolytic Effects.

Zebrafish (Danio rerio) is a popular and valuable species used in many different biomedical research areas. The complex behavior that fish exhibit in response to different stimuli allows researchers to explore the biological and pharmacological basis of affective and mood disorders. In this sense, anxiety is commonly studied in preclinical research with animal models in rodents. During the last decade, those models have been successfully adapted to zebrafish. Stressful stimuli, such as novel environments, chemical substances, light conditions, and predator images, can trigger defensive behaviors considered indicators of an anxiety-like state. In the first stage, models were adapted and validated with different stressors and anxiolytic drugs with promising results and are now successfully used to generate scientific knowledge. In that sense, zebrafish allows several routes of administration and other methodological advantages to explore the anxiolytic effects of natural products in behavioral tests as novel tank, light-dark chamber, and black/white maze, among others. The present work will review the main findings on preclinical research using adult zebrafish to explore anxiolytics effects of natural products as plant secondary metabolites such as flavonoids, alkaloids and terpenes or standardized extracts of plants, among others. Scientific literature confirms the utility of zebrafish tests to explore anxiety-like states and anxiolytic-like effects of plant secondary metabolites, which represent a useful and ethical tool in the first stages of behavioral.

Chrysin reduces anxiety-like behavior through actions on GABAA receptors during metestrus-diestrus in the rat.

Low concentrations of ovarian hormones, among other factors, are associated with greater vulnerability to negative effects of environmental stressors and may trigger anxiety symptoms in females. The flavonoid chrysin (5,7-dihydroxyflavone) exerts anxiolytic-like effects in male and ovariectomized female rats, but it is unknown if chrysin could reduce anxiety-like behavior that naturally occurs through the ovarian cycle phases. The present study evaluated the effect of chrysin on anxiety-like behavior associated with the ovarian cycle phases in rats and the participation of γ-aminobutyric acid-A (GABAA) receptors in these actions. The acute effects of chrysin (2 mg/kg) were investigated in female cycling Wistar rats in the elevated plus maze, locomotor activity test, and light/dark test. Diazepam (2 mg/kg) was used as reference anxiolytic drug. The participation of GABAA receptor in the anxiolytic actions of chrysin was explored by pretreating the rats with the noncompetitive GABAA chloride ion channel antagonist picrotoxin (1 mg/kg). Chrysin and diazepam prevented anxiety-like behavior that was associated with the metestrus-diestrus phase in both the elevated plus maze and light/dark test, and these effects were reversed by picrotoxin, with no significant changes in spontaneous locomotor activity. No significant motor effects of chrysin were detected in either behavioral test during proestrus-estrus or metestrus-diestrus phases, whereas diazepam produced motor hypoactivity in the locomotor activity test during proestrus-estrus phase. These results indicate that the flavonoid chrysin prevents anxiety-like behavior that naturally occurs during metestrus-diestrus in two unconditioned models that are used to evaluate anxiety-like behavior, and these effects were mediated by actions on GABAA receptors.

Association Between Socio-Affective Symptoms and Glutathione and CD4 and CD8 Lymphocytes in College Students.

Background: The prevalence of anxiety and depression in young students is associated with biosocial factors and scholastic stress. However, few studies have evaluated emotional-affective symptoms that are related to the immune system and antioxidant parameters in young individuals without diagnoses of affective disorders. Aim: This study aims to assess the relationship between emotional-affective symptoms and glutathione concentrations and CD4 and CD8 lymphocyte counts in college students. Methods: College students (n = 177) completed standardized psychometric instruments, including the Perceived Stress Scale, Hamilton Anxiety Scale, Beck Depression Inventory, Familiar Social and Friends Support Scale, and Rosenberg Scale. Blood samples were biochemically analyzed. Analyses of variance were conducted between four groups according to symptom severity. Results: A considerable prevalence of stress, anxiety, and depression symptoms was observed and negatively correlated with self-esteem and socio-familiar support. Perceived stress was sexually dimorphic. Although biochemical parameters were within reference ranges, glutathione, CD4, and CD8 tended to be lower in participants with anxiety and depression symptoms, which may be of predictive value. Conclusion: The relationship between antioxidant/immune parameters and socio-affective scores is latent in undiagnosed college students who might develop affective disorders. The findings suggest that during the initial development of affective disorders, stress management strategies should be implemented to help college students cope with the academic load and monitor negative changes in their physiological state.

Chrysin (5,7-dihydroxyflavone) exerts anxiolytic-like effects through GABAA receptors in a surgical menopause model in rats.

The present study investigated the effects of the flavonoid chrysin (5,7-dihydroxyflavone) on anxiety-like behavior in rats in a model of surgical menopause and evaluated the participation of γ-aminobutyric acid-A (GABAA) receptors in these actions. At 12 weeks post-ovariectomy, the effects of different doses of chrysin (0.5, 1, 2, and 4 mg/kg) were evaluated in the elevated plus maze, light/dark test, and locomotor activity test, and comparisons were made with the clinically effective anxiolytic diazepam. The participation of GABAA receptors in the actions of chrysin was explored by pretreating the rats with the noncompetitive GABAA chloride ion channel antagonist picrotoxin (1 mg/kg). The results showed that chrysin (2 and 4 mg/kg) reduced anxiety-like behavior in both the elevated plus maze and light/dark test, and these effects were similar to diazepam. Pretreatment with picrotoxin had no effects on its own but prevented the anxiolytic-like effects of chrysin in both tests. Chrysin also increased rearing and grooming, without significantly altering the number of crossings in the locomotor activity test; these effects were also similar to diazepam. In conclusion, the flavonoid chrysin produced anxiolytic-like effects through actions on GABAA receptors in a model of surgical menopause in rats. These findings support the hypothesis that this flavonoid could be a future natural alternative for ameliorating symptoms of anxiety after surgical menopause in women.

The Phytoestrogen Genistein Produces Similar Effects as 17ß-Estradiol on Anxiety-Like Behavior in Rats at 12 Weeks after Ovariectomy.

The phytoestrogen genistein produces anxiolytic-like effects in ovariectomized rats, which highlights its potential therapeutic effect in ameliorating anxiety in surgical menopausal women. However, no studies have directly compared the effects of identical doses of genistein and 17ß-estradiol, the main estrogen used in hormone replacement therapy in menopausal women. The present study evaluated the anxiolytic-like effects of identical doses of genistein and 17ß-estradiol (0.045, 0.09, and 0.18 mg/kg/7 days, s.c.) in a surgical menopause model in rats in the elevated plus maze and locomotor activity tests at 12 weeks after ovariectomy. Additionally, the participation of estrogen receptor-ß in the anxiolytic-like effect of genistein and 17ß-estradiol was explored by previous administration of the 5 mg/kg tamoxifen antagonist. Genistein and 17ß-estradiol (0.09 and 0.18 mg/kg) similarly reduced anxiety-like behavior in the elevated plus maze and also increased the time spent grooming and rearing, without affecting crossing in locomotor activity test. These effects were blocked by tamoxifen. Present results indicate that the phytoestrogen genistein has a similar behavioral profile as 17ß-estradiol in rats at 12 weeks after ovariectomy through action at the estrogen receptor-ß. Thus genistein has potential for reducing anxiety-like behavior associated with low concentrations of ovarian hormones, which normally occurs during natural and surgical menopause.

[Detection of antileptospira antibodies in a vulnerable population of Ixhuatlancillo, Veracruz]. / Detección de anticuerpos antileptospira en una población vulnerable del municipio de Ixhuatlancillo, Veracruz.

OBJECTIVE: To determine the seroprevalence of Leptospira sp. in Ixhuatlancillo residents and their canine pets. METHODS: We detected the presence of anti-leptospira antibodies in a population of 29 dogs and 36 canine owners, the study consisted in two phases: 1) Management, invitation and application of surveys; 2) sampling to canines and positive canine owners. The samples were analyzed on the Veracruz State Laboratory, employing the microagglutination technique (MAT). Statistical analysis was performed using a 2 x 2 contingency table in order to know the relationship between two variables to test the possible independence of the two variables using the chi-square test. RESULTS: Prevalence of anti-leptospira antibodies in dogs was 66 %, predominantly tarassovi serovar (47 %); and the owners analyzed prevalence was 61 %, which also tarassovi serovar was most prevalent (78 %). CONCLUSIONS: Anti-leptospira antibodies were found in dogs (66 %) and its owners; the tarassovi serovar was the most prevalent, so that living with pets is a potent risk factor for infection by this bacterium.

Introducción: el objetivo de este artículo es determinar la seroprevalencia de Leptospira sp. en residentes del municipio de Ixhuatlancillo y sus mascotas del género canino. Métodos: se detectó la presencia de anticuerpos antileptospira en una población de 29 caninos y 36 dueños de los caninos, el estudio consistió en dos fases: a) gestión e invitación y aplicación de encuesta, y b) toma de muestra a caninos y a dueños de caninos positivos. Las muestras se analizaron en el Laboratorio Estatal de Veracruz, empleando la técnica de microaglutinación. El análisis estadístico se realizó empleando una tabla de contingencia de 2 x 2 para conocer la relación entre variables, para probar la posible independencia de las dos variables empleando la prueba de chi cuadrada. Resultados: la prevalencia de anticuerpos antileptospira encontrada en caninos fue del 66 %, predominando la serovariedad tarassovi (47 %); la prevalencia hallada en los dueños analizados fue del 61 %, donde también la serovariedad tarassovi fue la de mayor prevalencia (78 %). Conclusiones: se hallaron anticuerpos antileptospira en caninos (66 %) y sus dueños, la serovariedad tarassovi fue la de mayor prevalencia, por lo que la convivencia con mascotas es un factor de riesgo potente para infectarse por esta bacteria.