J. Bhattacharyya et al., SKELETAL-MUSCLE CA-2+ FLUX AND CATABOLIC RESPONSE DURING SEPSIS, The American journal of physiology, 265(3), 1993, pp. 180000487-180000493
Membrane Ca2+ flux and net protein catabolism were studied in the skel
etal muscle during experimental sepsis. Sterilized rat fecal pellets w
ith (septic) or without (sterile) gram-negative bacteria, Escherichia
coli [10(2) colony-forming units (cfu)] and Bacteroides fragilis (2 X
10(3) cfu), were implanted into the abdomens of male Sprague-Dawley ra
ts (110-120 g). Septic and sterile rats were febrile and hyperlactacid
emic on day 1 postimplantation. These responses subsided by day 2 in s
terile but not septic rats. Initial Ca2+ flux, estimated from measurem
ents of Ca-45 uptake by soleus muscles in vitro, was elevated on day 1
in both sterile and septic rats and on day 2 and 3 in septic rats onl
y. The septic rat soleus muscle showed a significantly increased net p
rotein catabolic response (measured as tyrosine release by soleus musc
le, in vitro) over that found in muscles of sterile rats on day 1-3 po
stimplantation. The increase in Ca2+ flux in septic (day 1-3 postimpla
ntation) and sterile (day 1 only) rats was abolished when the rats wer
e treated with the calcium channel blocker diltiazem. In unoperated co
ntrol rat soleus muscles the Ca2+ ionophore, ionomycin, concomitantly
caused an increase in Ca2+ flux and net protein catabolism. Overall, t
he present study suggested that altered cellular Ca2+ regulation plays
a role in the net protein catabolic response in the skeletal muscle d
uring sepsis.