Effects of aging on proteasomal-ubiquitin system, oxidative stress balance and calcium homeostasis in middle-aged female rat colon.

Aging is a multifactorial process, which is considered as a decline over time. It is increasingly clear that there is a gender difference in aging and in the prevalence of age-related diseases as well. We aimed to examine the effects of the aging process in the colonic tissue of female Wistar rats aged 10 weeks (young) and 13 months (middle-aged) at an early stage, according to three main symptoms associated with aging: a decrease in the efficacy of the proteasome and muscle function and an increase in oxidative stress. The aging process was found to cause a significant decrease in ubiquitin C-terminal hydrolase ligase (UCHL-1) and a significant increase in 3-nitrotyrosine (3-NT), total glutathione (GSH), calcium (Ca2+), calcitonin gene-related peptide (CGRP) and superoxide dismutase (SOD) activity in middle-aged animals. In summary, it is suggested that the reduced activity of the proteasomal degradation system may be the result of the diminished expression of the UCHL-1 enzyme and the decreased levels of ubiquitin; furthermore, we found some key targets which may help to better understand the fundamental aging process.

Effects of aerobic workout on the changes in the characteristics of dynamics of the center of gravity in different age categories.

INTRODUCTION: The quality and function of movements undergo deterioration due to weight gain. Aerobic training normalizes body weight, improves the health status, and in addition, it is expected to improve the dynamics of movements. The aims of this study were to prove the beneficial effects of recreational physical activities on the movements. METHODS: Participants were divided into five different age categories: second childhood, adolescence, mature age I, mature age II, and aging. Squatting and vertical jumping of the participants were measured at the beginning and at the end of a 5-month training program. These movements simulated ordinary daily movements. Changes in the body were determined by InBody230. APAS 3D system was used for movement analysis. RESULTS: The results showed significant improvements in body weight, fat mass, muscle mass, fat mass-body weight ratio, muscle mass-body weight ratio, body mass index, body fat percentage, and waist-hip ratio. During jumping, the lifting and sinking of the center of gravity's (CG) position and its velocity and acceleration were improved. In case of squatting, the results showed significant improvements in the velocity and acceleration of dynamical characteristics of the CG. Other correlations were observed between changes in body composition and the dynamics of movements. DISCUSSION: The research proved that recreational training optimized body composition and improved the characteristics of CG's dynamics. The study suggests considerable connection between body composition and the characteristics of the movements' dynamics. From this point of view, our training program was the most effective in the working age groups.

Ghrelin-Induced Enhancement of Vasopressin and Oxytocin Secretion in Rat Neurohypophyseal Cell Cultures.

The effects of ghrelin on vasopressin and oxytocin secretion were studied in 13-14-day cell cultures of isolated rat neurohypophyseal tissue. The vasopressin and oxytocin contents of the supernatant were determined by radioimmunoassay after a 1- or 2-h incubation. Significantly increased levels of vasopressin and oxytocin production were detected in the cell culture media following ghrelin administration, depending on the ghrelin doses. The oxytocin level proved to be more elevated than that of vasopressin. The increase of vasopressin and oxytocin secretion could be totally blocked by previous administration of the ghrelin receptor antagonist ([D-Lys3]-growth hormone-releasing peptide-6). Application of the ghrelin receptor antagonist after ghrelin administration proved ineffective. The results indicate that vasopressin and oxytocin release is influenced directly by the ghrelin system, and the effects of ghrelin on vasopressin and oxytocin secretion from the neurohypophyseal tissue in rats can occur at the level of the posterior pituitary. Our observations lend support to the view that neurohypophysis contains ghrelin receptors.

Matrix metalloproteinase activity assays: Importance of zymography.

INTRODUCTION: Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases capable of degrading extracellular matrix, including the basement membrane. MMPs are associated with various physiological processes such as morphogenesis, angiogenesis, and tissue repair. Moreover, due to the novel non-matrix related intra- and extracellular targets of MMPs, dysregulation of MMP activity has been implicated in a number of acute and chronic pathological processes, such as arthritis, acute myocardial infarction, chronic heart failure, chronic obstructive pulmonary disease, inflammation, and cancer metastasis. MMPs are considered as viable drug targets in the therapy of the above diseases. METHODS: For the development of selective MMP inhibitor molecules, reliable methods are necessary for target validation and lead development. Here, we discuss the major methods used for MMP assays, focusing on substrate zymography. We highlight some problems frequently encountered during sample preparations, electrophoresis, and data analysis of zymograms. RESULTS AND DISCUSSION: Zymography is a widely used technique to study extracellular matrix-degrading enzymes, such as MMPs, from tissue extracts, cell cultures, serum or urine. This simple and sensitive technique identifies MMPs by the degradation of their substrate and by their molecular weight and therefore helps to understand the widespread role of MMPs in different pathologies and cellular pathways.

Cardiac capsaicin-sensitive sensory nerves regulate myocardial relaxation via S-nitrosylation of SERCA: role of peroxynitrite.

BACKGROUND AND PURPOSE: Sensory neuropathy develops in the presence of cardiovascular risk factors (e.g. diabetes, dyslipidemia), but its pathological consequences in the heart are unclear. We have previously shown that systemic sensory chemodenervation by capsaicin leads to impaired myocardial relaxation and diminished cardiac nitric oxide (NO) content. Here we examined the mechanism of diminished NO formation and if it may lead to a reduction of peroxynitrite (ONOO(-))-induced S-nitrosylation of sarcoendoplasmic reticulum Ca(2+)-ATPase (SERCA2a). EXPERIMENTAL APPROACH: Male Wistar rats were treated with capsaicin for 3 days to induce sensory chemodenervation. Seven days later, myocardial function and biochemical parameters were measured. KEY RESULTS: Capsaicin pretreatment significantly increased left ventricular end-diastolic pressure (LVEDP) decreased cardiac NO level, Ca(2+)-dependent NO synthase (NOS) activity, and NOS-3 mRNA. Myocardial superoxide content, xanthine oxidoreductase and NADPH oxidase activities did not change, although superoxide dismutase (SOD) activity increased. Myocardial and serum ONOO(-) concentration and S-nitrosylation of SERCA2a were significantly decreased. CONCLUSIONS AND IMPLICATIONS: Our results show that sensory chemodenervation decreases cardiac NO via decreased expression and activity of Ca(2+)-dependent NOS and increases SOD activity, thereby leading to decreased basal ONOO(-) formation and reduction of S-nitrosylation of SERCA2a, which causes impaired myocardial relaxation characterized by increased left ventricular end-diastolic pressure (LVEDP). This suggests that capsaicin sensitive sensory neurons regulate myocardial relaxation via maintaining basal ONOO(-) formation and SERCA S-nitrosylation.