The purpose of the study was to define effects of salt intake on tissue catecholamine concentration and physical function. Dahl salt-sensitive rats (DSS) and Dahl salt-resistant rats (DSR) were fed 0.4 or 8% salt food from 5 weeks old, of which tissue noradrenalin concentration (tNA) of 16 organs were analyzed. tNA markedly decreased in DSS with 8% salt food, and there were large organ differences in decrease of tNA in response to high salt intake. To study whether baroreceptor reflex plays a role in a salt-induced decrease of tNA, we repeated the same experiment on DSS and DSR with sinoaortic denervation and found that tNA did not decrease in response to high salt intake.
　Thus, the baroreceptor reflex may be involved in the salt-induced decrease of tNA by suppressing a noradrenalin production. To determine whether the salt-induced decrease of tNA is a common phenomenon also to fish, tNA of 15 organs of sea, estuary and river salmons were analy-zed, tNA of sea salmon were lower than river salmon. Therefore, the salt -induced decrease of tNA is common even to fish. To study the effect of high salt intake on physical function, daily and cumulative movements were measured on rats with and without infusion of 0.9 or 9% NaCl solution into the portal vein (PV) or inferior vena cava (IV). Intra-PV and-IV infusions of 9% NaCl significantly suppressed rat's movements. These results allow us to conclude that the high salt intake significantly decreased tNA and movement.

DESCENTE SPORTS SCIENCE Vol.17/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE