change in renal sympathetic nerve activity to change in intracerebroventricular sodium concentration ratio 2013-01-07T15:44:48Z A calculated measurement in which the change in the activity, i.e., the recordable electrical energy, of the renal sympathetic nerves between two points in time or two conditions is compared to the concentration of a solution of sodium, the chemical element with atomic number 11, infused directly into the ventricle(s) of the brain; calculated as the slope of the curve of renal sympathetic nerve activity versus intracerebroventricular-infused sodium concentration. A renal sympathetic nerve is a nerve (a cordlike structure that conveys impulses between the central nervous system and one or more parts of the body, and that consists of an outer connective tissue sheath surrounding a bundle of conductive fibers) of the autonomic nervous system that regulates involuntary and automatic reactions, especially to stress, associated with and controlling activity of the kidneys. CMO:0001238 JSmith change in RSNA to change in intracerebroventricular sodium concentration ratio clinical_measurement_ontology ratio of change in renal sympathetic nerve activity