AGE-DEPENDENT CHANGES OF BAROREFLEX EFFICIENCY IN DAHL RATS - EFFECTSOF HIGH-SALT INTAKE

The age-dependent changes in baroreflex control of heart rate were stu died in inbred Dahl rats. At the age of 8 weeks the baroreflex slope w as significantly greater in salt-resistant (R/Jr) than in salt-sensiti ve (S/Jr) rats fed a low-salt diet. The reverse was true in 16-week-ol d animals. High salt Intake (8 % NaCl diet for 4 weeks) suppressed bar oreflex efficiency in both age groups of S/Jr animals whereas no effec ts occurred in R/Jr rats. Baroreflex slope was, however, significantly lower in young S/Jr rats with a severe form of salt hypertension than in adult salt-loaded S/Jr rats in which only a moderate blood pressur e elevation was observed.