Multiple Blood Pressure loci on rat Chromosome 18 attenuate the development of hypertension in the Dahl S Hypertensive rat

Abstract

The aim of the present study was to identify the region within Chr 18 involved in the development of salt‐induced hypertension in the Dahl salt‐sensitive (SS) rat. Previous linkage and chromosomal substitution studies suggest the presence of a locus for salt‐sensitive hypertension in chr 18. Consomic SS‐18BN rats were backcrossed to the SS rat, and the offspring intercrossed to generate eight overlapping congenic strains covering the entire length of chr 18. Blood pressure and protein excretion were measured by telemetry in male rats during low salt and three weeks of high salt diet (8% NaCl) in parental (SS and SS‐18BN) and congenic strains. Mean arterial pressure (MAP) did not differ significantly between any of the strains studied during low salt diet. After three weeks of high salt, SS rats developed hypertension (MAP 1734 mmHg), while in the SS‐18BN consomics the development of hypertension was significantly attenuated (MAP 1485.5 mmHg). Characterization of the overlapping congenic strains suggests that there are at least five regions in chr 18 that are involved in the response of blodd pressure to a high salt diet in the SS rats.