EUROPATHWAYS INVOLVED IN THE REGULATION OF CIRCULATING VOLUME
Water deprivation and hypernatremia constitute challenges that could threaten the survival of organism. Despite the wide variation in daily intakes and losses of sodium and water, their concentrations in body fluids must be maintained within narrow limits. Hence, it is no surprise that multiple mechanisms and neural pathways are involved in the cardiovascular regulation of volume and composition of the extracellular fluid. This wide variety of mechanism ranges from localized and highly specific renal control of sodium to the complex control of ingestive behaviors. This review discloses the cardiovascular - renal interaction and summarizes some findings in the literature on central mechanisms underlying cardiovascular responses to the changes in circulating volume. These central mechanisms include projections from the carotid afferents to medullary catecholaminergic relays in the nucleus tractus solitarii and caudal ventrolateral medulla to connect the median preoptic nucleus in the forebrain. Finally, we reviewed recent literature data that suggest the involvement of these aforementioned pathways: i. in the effects of hypertonic saline on cardiovascular recovery from hypovolemic hemorrhagic shock; ii. and in the maintenance of high level of arterial blood pressure observed in experimental models of hypertension