Cardiac and splenic norepinephrine turnover during septic peritonitis.

Postganglionic sympathetic activity was assessed in heart and spleen tissue in conscious rats under conditions of developing septic shock by quantitating norepinephrine (NE) turnover. Fasted male rats were subjected to cecal ligation and puncture and allowed to recover for 12-14 h. NE turnovers were measured by following the rate of [3H]NE decay, and measurements were made between 12 and 24 h after surgery. Plasma glucose and lactate were determined at times throughout the turnover protocol. NE turnover in cardiac tissue of septic animals was increased (0.134 micrograms X g-1 X h-1) in comparison with both surgical sham (0.052 micrograms X g-1 X h-1) and unoperated controls (0.051 micrograms X g-1 X h-1). NE turnover rates were also elevated in spleen tissue of septic rats (0.152 micrograms X g-1 X h-1) in comparison with both surgical sham (0.094 micrograms X g-1 X h-1) and unoperated controls (0.087 micrograms X g-1 X h-1). Plasma glucose levels suggest that septic rats are in the hyperglycemic phase of sepsis. These experiments support the concept of increased peripheral sympathetic outflow during the development of septic shock that would support hypermetabolic and subsequent hyperdynamic alterations which are well-recognized characteristics of the early stages of sepsis leading to septic shock.