Grant: CIHR/Regional Partnership Program/Operating Grants

Proper cardiovascular function in mammals depends on keeping the concentration of salts in the blood at a constant level. A critical part of this regulation are neurons in the brain that sense changes in saltiness (or osmolality) and release a hormone (vasopressin or VP) that regulates the amount of water that is excreted from the kidney. When the body experiences a sustained increase in osmolality, these cells (the MNCs) undergo remarkable changes in shape and size and in their functional components that enable them to increase their release of VP for the long term. We have found similar changes occur in MNCs that have been removed from rat brains and are maintained in tissue culture dishes, and this will enable us to study the biochemical events that lead to these changes. We therefore propose to study how the MNCs adapt to sustained increases in osmolality and how these changes affect the ability of the MNCs to release hormones. This will help us to understand how the body maintains the critical blood parameter of osmolality in response to a sustained challenge and how neurons can undergo reversible changes in structure and function.