[The effect of burn sera on the calcium homeostasis in isolated rat myocardial cells].
OBJECTIVE
To study the effect of burn sera on the calcium homeostasis in isolated rat myocardial cells.


METHODS
The burn sera were obtained from the Sprague -- Dawley (SD) rats inflicted by 30% TBSA III degree burn at 2, 4 and 6 postburn hours with the harvesting of burn sera at different postburn times, named as 2 hBS, 4hBS and 6 hBS, respectively. Myocardial cells were isolated by enzyme digestion with retrograde perfusion apparatus. [Ca(2+)]i was detected with the fluorescent dye Fura -- 2 and L -- type calcium (ICa -- L) currents were recorded in the whole -- cell patch -- clamp model.


RESULTS
Myocardial cellular [Ca(2+)]i became much higher in concent after being in cubated with sera, especially with 6hBS, than that in normal myocardial cells (P < 0.01). But the effect of 6hBS could be significantly inhibited by verapamil (30 nmol/L), the calcium channel antagonist and procaine (2 mmol/L), the inhibitor of rynodine receptor (P < 0.01) by 47.7% and 67.6%, respectively. Ca -- L was evidently increased by the stimulation of 2 hBS and 6 hBS, by 50 -- 80% and 1.5 -- 2.5 folds, respectively. It was indicated by I -- V curves that every ICa caused by depolarizaton and clamp voltage was increased by burn sera, which further made the maximal activating voltage ahead of time. All the burn sera effects on calcium current could be removed by extracellular lavage.


CONCLUSIONS
The myocardial [Ca(2+)]i and ICa -- L could increase significantly when affected by burn sera. The alteration in calcium homeostasis might be a cellular mechanism of myocardial injury.
Shen
H
H
Department of Burns, Changhai Hospital, The Second Military Medical University, Shanghai 200433 P.R. China.
Chen
Y
Y
Liu
S
S
D000818:Animals; D002056:Burns / Q000097:blood*; D002118:Calcium / Q000378:metabolism*; D005260:Female; D006706:Homeostasis; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011343:Procaine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014700:Verapamil / Q000494:pharmacology
D011343:Procaine; D014700:Verapamil; D002118:Calcium