Implications of angiotensin II in central nervous system on exercise performance.

The renin-angiotensin system (RAS) consists of a complex enzyme-peptide system, which, besides from functioning as a circulating endocrine system, is also intrinsic in many organs and tissues, including the brain. Although the RAS generates a family of biological active peptides, angiotensin II (Ang II) is still considered one of its main mediators and effectors. Ang II produces many well defined and potent effects through AT1 and AT2 receptors and its physiological applications are yet expanding. Recently, it has been proposed that Ang II, acting both centrally and peripherally, interferes on exercise performance due to its influence on multiple functions within the organism. This hypothesis is also supported by evidences reporting an increased frequency of the ACE I allele among elite athletes, suggesting that this is a genetic factor that influences physical performance. The fatigue resulting from physical exercise is a multifactorial phenomenon that comprises the interaction between physiological factors of peripheral and/or central origin. To that extent, the Ang II-mediated events on factors that affect exercise performance such as cardiovascular, metabolic and thermoregulatory adjustments as well as cerebral metabolism and neurohumoral or neurotransmitter turnover, implicate the peptide in the genesis of exercise-induced fatigue. This mini-review focuses on how exercise-induced physiological adjustments are influenced by Ang II within the central nervous system and how these effects may limit athletic performance.

Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae: a brief theoretical discussion of likely scenarios

Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.