A Brain–Kidney Connection: The Delicate Interplay of Brain and Kidney Physiology

Excerpt

The central nervous system (CNS) and kidneys are strongly interconnected. Afferent impulses from the CNS regulate renal blood flow, glomerular filtration rate (GFR), and affect renal sodium handling [1]. Vasopressin hormone is secreted from the posterior pituitary gland and acts on the collecting ducts of the distal nephron to regulate water balance and serum osmolality. However, the kidney is not a target organ that solely responds to impulses from the CNS. Impulses originating from the kidney are carried via unmyelinated and thinly myelinated fibers to the CNS and the contralateral kidney to regulate CNS activity and coordinate renal sodium handling with the contralateral kidney. In animal models with acute kidney injury (AKI), the levels of inflammatory cytokines increase in the brain with evidence of anatomic and functional brain injuries [2]. Both organs also share a common feature—a tight autoregulatory mechanism that maintains constant blood flow over a wide range of blood pressures. It is unclear, however, whether both the renal and brain autoregulatory mechanisms are interconnected in such a way that changes that occur in one organ affect the blood flow in the other. …