The Irritable Bowel Syndrome: How Stress Can Affect the Amygdala Activity and the Brain-Gut Axis

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Coral life as probed by their fluorescence emission

Coral health was assessed by monitoring the photosynthetic activity of their zooxanthellae using the fast chlorophyll a fluorescence rise 0-J-I-P (Strasser et al. 2000). This type of measurement has the advantage of being non-invasive. Three species of recently collected Anthozoa were being studied: two species of Actinodiscus from Bali (Indonesia) and one colony of Porites porites from St Lucia (Lesser Antilles). The collected data were analysed according to the JIP-test (Strasser et al. 2000). Clear circadian rhythms were found in all calculated fluorescence parameters. The measurements are sensitive to random noise caused by for example movements of the polyps. We chose to study the maximum quantum efficiency of PSII (ϕPo) for its relative insensivity to this noise and the performance index (PIABS) as a reflection of all photosynthetic processes in PSII. The peaks and troughs of the circadian oscillations did not coincide with the rhythm of the ambient light in the aquarium. Long-term experiments with light cycles are reported

Endogenous expression and in vitro study of CRF-related peptides and CRF receptors in the rat gastric antrum.

International audienceIn vivo studies suggest that corticotrophin-releasing factor (CRF) and CRF-like peptides, urocortin 1 (UCN 1) and UCN 2, inhibit gastric emptying and stimulate colonic motility through CRF2 and CRF1 receptors, respectively. We evaluated expression and functions of CRF, UCN 1, UCN 2 and CRF1 and CRF2 receptors in the rat gastric antrum. Tissues were processed for immunohistochemistry and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). In vitro studies were performed to test the functional significance of CRF, UCN 1 and UCN 2. Some experiments were realized in the presence of specific CRF1 or CRF2 receptors antagonists. CRF1 and CRF2 receptors-like immunoreactivity (CRF1 and CRF2 receptors-LI) was localized in fibers and neurons of the myenteric ganglia. CRF1 and CRF2 receptors-LI was also found in nerve fibers distributed in the muscle layers. CRF- and UCN 1-LI was observed in neuronal cell bodies of the myenteric ganglia and in numerous nerve fibers running parallel to smooth muscle cells. Quantitative RT-PCR demonstrated UCN 2, CRF1 and CRF2 receptors expressions in both muscle layers and mucosa of the gastric antrum. Functional studies showed that CRF, UCN 1 and UCN 2 decreased antral phasic contractions. CRF(1) receptor antagonist (CP-154,526) did not block CRF-like peptides-induced inhibition of antral motility. In contrast, a CRF2 receptor antagonist (Astressin2-B) blocked the effects of CRF-like peptides on the antral muscle contractions. These results demonstrate (1) the presence of CRF, UCN and CRF1 and CRF2 receptors in the rat gastric antrum; (2) that, in vitro, CRF-like peptides inhibit phasic contractions of the antrum through CRF2 receptor. These results strongly suggest that CRF-like peptides play a major role in the regulatory mechanisms that underlie the neural control of gastric motility through CRF2 receptor

Assessing the zoantharian diversity of the tropical eastern pacific through an integrative approach

Zoantharians represent a group of marine invertebrates widely distributed from shallow waters to the deep sea. Despite a high diversity and abundance in the rocky reefs of the Pacific Ocean, very few studies have been reported on the diversity of this group in the Tropical Eastern Pacific coasts. While molecular techniques recently clarified some taxonomic relationships within the order, the taxonomy of zoantharians is still highly challenging due to a lack of clear morphological characters and confusing use of different data in previous studies. Our first insight into the zoantharian diversity at El Pelado Marine Protected Area - Ecuador led to the identification of six species: Terrazoanthus patagonichus; Terrazoanthus sp.; Antipathozoanthus hickmani; Parazoanthus darwini; Zoanthus cf. pulchellus; and Zoanthus cf. sociatus. A metabolomic approach using UHPLC-HRMS was proven to be very efficient as a complementary tool in the systematics of these species and specialized metabolites of the ecdysteroid and alkaloid families were identified as key biomarkers for interspecific discrimination. These results show good promise for an application of this integrative approach to other zoantharians

Anti-inflammatory effect of vagus nerve stimulation in a rat model of inflammatory bowel disease.

International audienceVagus nerve stimulation of afferents is used as an adjunctive treatment for drug-resistant epilepsy and depression. In addition, anti-inflammatory properties of vagus nerve stimulation have been reported in various experimental models of inflammation but not in colitis. These effects are thought to be mediated via peripheral release of acetylcholine from the vagus and subsequent activation of macrophages. Our aim was to evaluate in rats the anti-inflammatory effects of chronic vagus nerve stimulation on colonic inflammation. Colitis was induced by intracolonic instillation of trinitrobenzene sulfonic acid. Vagus nerve stimulation (left cervical) was performed in freely moving animals 3 h per day for five consecutive days. Assessment of colonic inflammation was obtained using physiological (e.g. body weight, temperature and locomotor activity) parameters, macroscopical (area of lesions), histological, and biological parameters (e.g. myeloperoxidase activity, cytokine and cytokine-related mRNAs), both at the level of the damaged colon and the colon immediately above. A global multivariate index of colitis was then generated for a better characterization of colonic inflammation. Vagus nerve stimulation reduced the degree of body weight loss and inflammatory markers as observed above the lesion by histological score and myeloperoxidase quantification. This anti-inflammatory effect was also demonstrated by the improvement of the multivariate index of colitis. These data argue for an anti-inflammatory role of vagus nerve stimulation chronically performed in freely moving rats with colitis and provide potential therapeutic applications for patients with inflammatory bowel diseases