Effects of physical exercise on sodium appetite in rats

• Grant number: 12/20554-8
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2013
• End date: April 30, 2015
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Roberto Lopes de Almeida
• Grantee: Roberto Lopes de Almeida
• Host Institution: Faculdade de Medicina do ABC (FMABC). Organização Social de Saúde. Fundação do ABC. Santo André , SP, Brazil
• Associated researchers: Cristiana Akemi Ogihara ; Monica Akemi Sato

Abstract

The maintenance of appropriate body fluid volume is necessary for the constancy of the internal medium by regulation within narrow limits of the amount of the ion sodium since this is the main determinant of the volume and osmolality in the body. To maintain the constancy, the body creates regulatory mechanisms to increase water consumption upon deficiency of body fluid which is called thirst and to increase sodium intake which is called sodium appetite. The preference for sodium is increased in situations where there is a hydromineral imbalance as the administration of diuretics accompanied by a low sodium diet, water deprivation, hemodialysis, pregnancy and exercise. On appearance of thirst and sodium appetite is also seen an increase in the level of hormones that act to decrease the excretion of sodium and water. Exercise is an example of stimulus that can induce a change in hydromineral balance, but few studies show a direct correlation between exercise and onset of sodium appetite in rats. Exercise promotes increased sympathoexcitability. Early evidence shows that increased sympathetic nerve activity may increase release of renin and consequently activate the renin-angiotensin-aldosterone system. It is well known that activation of this system may cause increased behavioral responses of thirst and sodium appetite. However, no previous study has shown that physical exercise could increase the sodium appetite in rats. Thus, it becomes interesting to investigate if exercise induces increase sodium appetite, and also if this could change the autonomic balance in the animals. (AU)