Alternation of Na(+)-Ca2+ exchange in rat cardiac sarcolemmal membranes during different phases of sepsis.
OBJECTIVE
To study the alteration of Na(+)-Ca2+ exchange in rat cardiac sarcolemmal membrane during phases of septic shock.


METHODS
Sepsis was induced by cecal ligation and puncture (CLP). Na(+)-Ca2+ exchange was assayed by radioactive analysis.


RESULTS
Na(+)-dependent 45Ca2+ uptake was decreased by 62%-69% in late phase of sepsis, whereas it was not affected in early phase of sepsis. Na(+)-Ca2+ exchange stimulated by 5' guanylyl imidodiphosphate [Gpp (NH) p] was decreased by 65.7% in late phase of sepsis but unaltered in early phase of sepsis. Two agonists (angiotensin II and phenylephrine) coupled to Gq and a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA) all inhibited Na(+)-Ca2+ exchange in late phase of sepsis. Na(+)-Ca2+ exchange activities induced by phosphorylation of Na(+)-Ca2+ exchange were decreased in late phase of sepsis, whereas inhibition of Na(+)-Ca2+ exchange by dephosphorylation was increased both in early and late phases of sepsis.


CONCLUSIONS
The alteration of Na(+)-Ca2+ exchange during different phases of sepsis might be related to the activities of Gq, protein kinase C, and phosphorylation/dephosphorylation.
Wang
X
X
Institute of Cardiovascular Research, First Hospital, Beijing Medical University, Beijing 100034, China.
Yang
J
J
Dong
L
L
Pang
Y
Y
Su
J
J
Tang
C
C
Liu
N
N
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000378:metabolism*; D018805:Sepsis / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D006165:Guanylyl Imidodiphosphate; D012964:Sodium; D002118:Calcium