TPN-induced sympathetic activation is related to diet, bacterial translocation, and an intravenous line.
OBJECTIVE
To investigate the effects of an intravenous line and the administration of a total parenteral nutrition (TPN) formula by the parenteral and oral routes on bacterial translocation and urinary catecholamine excretion in rodents.


METHODS
Rats were fed chow with or without an intravenous line and a fat-free TPN solution either orally or intravenously for 5 consecutive days. Urine was collected on the first, third, and fifth days of feeding and quantitatively analyzed for norepinephrine and epinephrine excretion. Mesenteric lymph nodes were cultured for bacteria at the end of the study (day 5).


RESULTS
Oral and intravenous TPN diets significantly increased norepinephrine excretion over time (P < .0001) compared with excretion in rats fed chow. Oral TPN diets increased epinephrine secretion after 5 days of feeding. The route of feeding TPN solution had no effect on norepinephrine or epinephrine excretion. Chow-fed rats with intravenous lines tended to have increased norepinephrine excretion over 5 days of feeding compared with chow-fed rats without intravenous lines (55% vs 13%, P = .08). Rats with bacterial translocation had greater norepinephrine excretion (mean +/- SEM, 136 +/- 23 pmol/mumol of creatinine) than rats without bacterial translocation (64 +/- 14 pmol/mumol of creatinine) (P < .05).


CONCLUSIONS
Intravenous and oral fat-free, hypertonic glucose diets increase sympathetic nervous activity. This diet-induced sympathetic activity may be related to the presence of an intravenous line, bacterial translocation, the thermic effects of hypertonic glucose, and/or the absence of orally ingested food substances in rodent chow. In this model of rodent feeding, increased sympathetic activity may account for alterations in intestinal and immunologic defenses.
Department of Surgery, University of Washington, Seattle.
W S
WS
Helton
M
M
Rockwell
R M
RM
Garcia
R V
RV
Maier
M
M
Heitkemper
D000284:Administration, Oral; D000818:Animals; D001419:Bacteria / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D004032:Diet; D018752:Diet, Fat-Restricted; D004750:Enteral Nutrition; D004837:Epinephrine / Q000652:urine; D005526:Food, Formulated; D005950:Glucose Solution, Hypertonic; D007262:Infusions, Intravenous / Q000295:instrumentation; D008198:Lymph Nodes / Q000382:microbiology; D008297:Male; D008643:Mesentery / Q000382:microbiology; D009638:Norepinephrine / Q000652:urine; D010289:Parenteral Nutrition, Total / Q000295:instrumentation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D015430:Weight Gain
D005950:Glucose Solution, Hypertonic; D009638:Norepinephrine; D004837:Epinephrine