CONTRIBUTION OF DEPRESSED REUPTAKE TO THE DEPLETION OF NOREPINEPHRINE FROM RAT-HEART AND SPLEEN DURING ENDOTOXIN-SHOCK

  • 1 January 1982
    • journal article
    • research article
    • Vol. 9  (2) , 129-143
Abstract
Norepinephrine content (.mu.g/g) was depressed in hearts and spleens of fasted male Holtzman rats treated i.v. with Salmonella enteritidis lipopolysaccharide (14-17 mg/kg). To investigate the mechanism of norepinephrine depletion during endotoxicosis, in vivo norepinephrine reuptake was evaluated in control and severely shocked rats using the incorporation of 3H-norepinephrine into hearts and spleens. Incorporation of 3H-norepinephrine into spleens of endotoxic rats was reduced 88%, i.e., from a control of 2309 .+-. 224 dpm/g to 270 .+-. 69 dpm/g after endotoxin. In contrast, cardiac tissue incorporation of 3H-norepinephrine was not significantly impaired, i.e., control of 11838 .+-. 845 dpm/g vs. severe shock of 17783 .+-. 2904 dpm/g. In vitro analysis of total norepinephrine retained in cardiac and splenic tissue slices incubated with 3H-norepinephrine yielded resulted results consistent with in vivo experiments: splenic norepinephrine reuptake was significantly decreased on the order of 50% in preparations from endotoxic rats, while myocardial norepinephrine reuptake was the same in both groups. Thus, depression of norepinephrine reuptake is evidently a mechanism of norepinephrine depletion in spleens but not hearts of endotoxic rats.