Initiation, duration and dissipation of diet-induced changes in sympathetic nervous system activity in the rat.

Previous studies in this laboratory have demonstrated that 48 hr of fasting suppresses and 72 hr of sucrose feeding (a model of voluntary overfeeding) stimulates sympathetic nervous system activity in rats. The experiments described here were undertaken to establish whether these diet-induced change in sympathetic activity occur in the early phases of a fast and whether they persist beyond a 3 day period of overfeeding. The results indicate that changes in cardiac norepinephrine turnover can be detected during the first 24 hr of fasting or overfeeding, and that the increase in cardiac norepinephrine turnover induced by sucrose overfeeding is sustained over 8 days of sucrose administration.