CENTRAL AND PERIPHERAL EFFECT OF MPTP VIA DOSE-DEPENDENT MAGNESIUM MODULATION.

Background: Recent studies suggested that MPTP could cause gastrointestinal motility deficits additionally to its nonconclusive and controverted effects on the CNS (behavior and brain oxidative stress) in rats. A possible interaction between MPTP typical impairments and magnesium modulatory potential was previously suggested, as magnesium role was described in neuroprotection, gastrointestinal function, and oxidative stress. Aim: To investigate the possible modulatory effect of several magnesium intake formulations (via drinking water) in MPTP neurotoxicity and functional gastrointestinal impairment induction. Materials and Methods: Adult male Wistar rats were subjected to 3-week magnesium intake-controlled diets (magnesium depleted food and magnesium enriched drinking water) previously to acute subcutaneous MPTP treatment (30 mg/ kg body weight). Gastrointestinal motility (one hour stool collection test), and behavioral patterns (Y maze task, elevated plus maze test, open field test, forced swim test) were evaluated. Followingly, brain and bowel samples were collected, and oxidative stress was evaluated (glutathione peroxidase activity, malondial-dehyde concentrations). Results: MPTP could lead to magnesium intake-dependent constipation-like gastrointestinal motility impairments, anxiety- and depressive-like affective behavior changes, and mild pain tolerance defects. Also, we found similar brain and intestinal patterns in magnesium-dependent oxidative stress. Conclusion: While the MPTP effects in normal magnesium intake could be regarded as not fully relevant in rat models and limited to the current experimental conditions, the abnormalities observed in the affective behavior, gastrointestinal status, pain tolerance, peripheric and central oxidative status could be indicative of the extent of the systemic effects of MPTP that are not restricted to the CNS level, but also to gastro-intestinal system.

PERCEIVED STRESS AND GASTROINTESTINAL HABITS IN COLLEGE STUDENTS.

CONTEXT: Many negative effects of stress regarding cognitive performances and gastrointestinal habits were previously reported in both animal models and human participants. OBJECTIVE: We aimed to compare perceived stress levels with declared gastrointestinal habits changes in a small cohort of college students during academic acquisition and evaluation periods. DESIGN: College students were recruited and divided into two groups: the control group evaluated during the acquisition period of the academic year and the stressed group evaluated during the examination period. SUBJECT AND METHODS: The students' psychological and gastrointestinal status was evaluated using a common stress questionnaire and a gastrointestinal habits survey. RESULTS: Our results showed increased perceived stress in college students during stressful conditions, as compared to lesser demanding periods. Similarly, more than 40%of the participants declared that gastrointestinal habits changes occurred during stressful periods. We observed significant correlations between the perceived stress levels and gastrointestinal habits changes. CONCLUSION: This small-sized survey study showed that the occurrence of the stressful event in young adults recorded higher perceived stress scores and frequent functional gastrointestinal symptoms, as compared to the lower stressful periods. Also, we showed that functional gastrointestinal symptoms are rather common and could be regarded as a negative response to stress.

IS OXYTOCIN RELEVANT FOR THE AFFECTIVE DISORDERS?

Oxytocin is a complex molecule involved in a variety of biological processes at both the central and the peripheral level. Although its role was initially associated almost exclusively with birth and breastfeeding, recent studies are suggesting that in fact oxytocin could be involved in many other physiological and pathological processes. In this way, lately there is a growing interest towards a possible involvement of oxytocin in many etiopathogenic and psychopathological processes, as for example in the affective disorders, where the roles of oxytocin are not yet clearly understood. In this paper we shortly describe the main aspects regarding the relevance of oxytocin administration or its mechanisms in the affective disorders, as well as its relations with the hypothalamic-pituitary-adrenal axis and cortisol secretion. It seems that although the researches on the importance of oxytocin in the affective disorders are rather at the beginning, an increasing number of evidence is supporting the involvement of oxytocin in the pathogenic processes of these psychiatric disorders. Still, the studies covering this topic are still in their early days, and the results that are trying to understand if there is a major role of oxytocin in affective disorders are not consistent enough to draw definitive conclusions and establish with certainty where the place of oxytocin in the affective disorders pathology is.