The Foundational Science of Endogenous Opioids and Their Receptors.

The function of endogenous opioids spans from initiating behaviors that are critical for survival, to responding to rapidly changing environmental conditions. A network of interconnected systems throughout the body characterizes the endogenous opioid system (EOS). EOS receptors for beta-endorphin, enkephalin, dynorphin, and endomorphin underpin the diverse functions of the EOS across biological systems. This chapter presents a succinct yet comprehensive summary of the structure of the EOS, EOS receptors, and their relationship to other biological systems.

Effects of moderate exercise and a multiple vitamin and mineral complex on the arterial wall.

BACKGROUND: Aerobic exercise has favorable effects on vascular structure and function. Its beneficial role may be due to a decrease in oxidative stress. The association of vitamin and mineral supplements to exercise determined contradictory effects on arterial wall and oxidative stress parameters. The aim of this experimental study was to evaluate the effect of moderate aerobic exercise, alone or in association with a vitamin and mineral complex, on aortic wall morphology and oxidant/antioxidant balance. MATERIALS AND METHODS: Four groups, each of 10 Wistar rats, were included in the study, as follows: (I) sedentary controls, (II) group subjected to physical exercise, (III) group subjected to physical exercise and nutritional supplement, and (IV) sedentary nutritional supplemented group. Aortic wall histological examinations and serum and aortic wall oxidative stress measurements were performed in each group. RESULTS: Moderate aerobic exercise induces vascular smooth muscle cell hypertrophy and transformation in a secretory phenotype. There was a trend for increase in malondialdehyde (MDA) and decrease in thiol (SH) groups in aortic tissue homogenates, together with reduction in serum MDA values and increase in SH groups, after exercise. A reduction in aortic wall lipid peroxidation was found in supplemented trained animals compared to sedentary group, while no influence on aortic structure was noted. CONCLUSIONS: Moderate aerobic exercise induces adaptive modifications in the arterial wall and a favorable effect on systemic oxidative response. The association of vitamin and mineral supplement did not influence significantly arterial morphology, while its effects on aortic oxidative stress suggest an increase in local antioxidant defense.