Adora2A downregulation promotes caffeine neuroprotective effect against LPS-induced neuroinflammation in the hippocampus.

Caffeine has been extensively studied in the context of CNS pathologies as many researchers have shown that consuming it reduces pro-inflammatory biomarkers, potentially delaying the progression of neurodegenerative pathologies. Several lines of evidence suggest that adenosine receptors, especially A1 and A2A receptors, are the main targets of its neuroprotective action. We found that caffeine pretreatment 15 min before LPS administration reduced the expression of Il1b in the hippocampus and striatum. The harmful modulation of caffeine-induced inflammatory response involved the downregulation of the expression of A2A receptors, especially in the hippocampus. Caffeine treatment alone promoted the downregulation of the adenosinergic receptor Adora2A; however, this promotion effect was reversed by LPS. Although administering caffeine increased the expression of the enzymes DNA methyltransferases 1 and 3A and decreased the expression of the demethylase enzyme Tet1, this effect was reversed by LPS in the hippocampus of mice that were administered Caffeine + LPS, relative to the basal condition; no significant differences were observed in the methylation status of the promoter regions of adenosine receptors. Finally, the bioinformatics analysis of the expanded network demonstrated the following results: the Adora2B gene connects the extended networks of the adenosine receptors Adora1 and Adora2A; the Mapk3 and Esr1 genes connect the extended Adora1 network; the Mapk4 and Arrb2 genes connect the extended Adora2A network with the extended network of the proinflammatory cytokine Il1ß. These results indicated that the anti-inflammatory effects of acute caffeine administration in the hippocampus may be mediated by a complex network of interdependencies between the Adora2B and Adora2A genes.

Depressive behavior induced by unpredictable chronic mild stress increases dentin hypersensitivity in rats.

OBJECTIVE: The present study evaluated the nociceptive response induced by dentin hypersensitivity after dental erosion in rats that were exhibited to unpredictable chronic mild stress (UCMS)-induced depressive-like behavior. DESIGN: Adult male rats were subjected to UCMS (depression [D] group) or not (no depression [ND] group) for 30days and received either acidic solution to induce dental erosion (E) or water (W), thus forming the WND, END, WD, and ED groups. After the end of treatment, depressive-like parameters (i.e., sucrose preference and immobility in the forced swim test) and dentin hypersensitivity were evaluated. Plasma tumor necrosis factor α (TNF-α) and corticosterone levels were measured, and astrocytic glial fibrillary acidic protein (GFAP) expression was evaluated in the prefrontal cortex, hippocampus, amygdala, and hypothalamus. RESULTS: Administration of the acidic solution potentiated dentin hypersensitivity and increased corticosterone levels in the ED group compared with the WD group. TNF-α levels only increased in the WD group. The ED group exhibited an increase in astrocytic GFAP expression in the hypothalamus and prefrontal cortex but decreases in the hippocampus. CONCLUSIONS: These results suggest that UCMS exacerbated the nociceptive response associated with dentin hypersensitivity, concomitant with an increase in plasma corticosterone levels. Hypothalamic and prefrontal cortex astrogliosis in the ED group may be attributable to the increase in corticosterone associated to UCMS procedure. The reduction of astrocytic GFAP expression in the hippocampus in the ED group supports the association between dentin hypersensitivity and depression.

Effects of perinatal period administration of clomiphene citrate in sexual behavior, organ weights and hormone concentration of Wistar male and female rats / Efeito da administração do citrato de clomifeno durante o período perinatal no comportamento sexual, peso dos órgãos e concentração hormonal de ratos Wistar machos e fêmeas

The effects of prenatal exposure to clomiphene citrate in sexual behavior, organ weight and hormone concentrations of male and female rats was evaluated. The animals received four doses of clomiphene citrate 2 mg/mL each during the prenatal period (21 days of gestation DG21) on days 1 (DN1), 2 (DN2) and 3 (DN3) after the birth of the puppies. The treatment led to the development of polycystic ovaries in 70% of the females, masculinization of female sexual behavior and changes in sexual behavior of males evidenced by the reduction in the number of ejaculations. In regards to hormone levels, a decrease in the FSH levels in male offspring was observed. It was concluded that clomiphene citrate interferes with the reproductive capacity of male and female rats and female sexual orientation when prenatally administered.

Foram investigados os efeitos da exposição perinatal ao citrato de clomifeno no comportamento sexual, peso dos órgãos e concentração hormonal de ratos machos e fêmeas. Os animais receberam quatro doses de 2 mg/mL de citrato de clomifeno, no período perinatal (21 dias de gestação DG21), nos dias 1 (DN1), 2 (DN2) e 3 (DN3) após o nascimento dos filhotes. O tratamento causou desenvolvimento de ovário policístico em 70% das fêmeas, masculinização do comportamento sexual das fêmeas e alteração do comportamento sexual dos machos evidenciado pela redução no número de ejaculações. Em relação aos níveis hormonais, observou-se diminuição de FSH na prole masculina. Concluiu-se que o citrato de clomifeno interfere na capacidade reprodutiva de ratos machos e fêmeas, e na orientação sexual de fêmeas, quando administrado perinatalmente.

Effects of propentofylline on CNS remyelination in the rat brainstem.

Propentofylline (PPF) is a xanthine derivative with pharmacological effects distinct from those of the classical methylxanthines. It depresses activation of microglial cells and astrocytes which is associated with neuronal damage during neural inflammation and hypoxia. The aim of this study was to evaluate whether PPF had the capacity of affecting glial cells behavior during the process of demyelination and remyelination following ethidium bromide (EB) gliotoxic injury. EB injection into the CNS is commonly used as an experimental demyelinating model inducing local oligodendroglial and astrocytic death, which results in primary demyelination, blood-brain barrier and glia limitans disruption and Schwann cells invasion. Sixty Wistar rats were divided into four different groups receiving 10 microlitres of 0.1% EB or 0.9% saline solution into the cisterna pontis and treated or not with the xanthine. PPF treatment was done using 12.5 mg/kg/day by the intraperitonial route for 31 days of the experimental period. The rats were euthanized from 7 to 31 days after EB injection and brainstem sections were collected and processed for light and transmission electron microscopy studies. Results from both groups were compared by using a semi-quantitative method developed for documenting in semithin sections the extent and nature of remyelination of demyelinating lesions. Results showed that PPF administration after EB injection significantly increased both oligodendroglial and Schwann cell remyelination at 31 days (mean remyelination scores of 3.67 ± 0.5 for oligodendrocytes and 1.27 ± 0.49 for Schwann cells) compared to untreated animals (scores of 3.19 ± 0.57 and 0.90 ± 0.33, respectively).

Behavioral and biochemical effects of xylazine: possible interactions between central noradrenergic-dopaminergic systems / Efeitos comportamentais e bioquímicos da xilazina: possíveis interações entre os sistemas noradrenérgico e dopaminérgico centrais

Behavioral and biochemical effects of xylazine were studied both in rats and mice. The results showed that xylazine: a) decreased the general activity of rats and mice observed in an open field; b) was unable to produce catatonia and suppressed haloperidol-induced catatonia in mice; c) increased apomorphine-induced stereotyped behavior in rats; and d) increased brain noradrenaline without effect on brain dopamine levels. These results were discussed in the light of a possible interference of xylazine with brain noradrenergic system and, thus, with the dynamic interaction between noradrenergic-dopaminergic neurons within the Central Nervous System.

Alguns efeitos comportamentais e bioquímicos da xilazina foram estudados em ratos e camundongos. Os resultados mostraram que a xilazina: a) diminuiu a atividade geral de ratos e camundongos observados em campo-aberto; b) foi incapaz de produzir catatonia e suprimiu este comportamento induzido pelo haloperidol em camundongos; c) potencializou o comportamento estereotipado induzido pela apomorfina em ratos; d) aumentou os níveis cerebrais de noradrenalina, porem não alterou aqueles de dopamina. Estes resultados foram discutidos considerando-se ação da xilazina em sislemas noradrenérgicos centrais e da interação entre sistemas noradrenérgicos e dopaminérgicos centrais.