Figure 1

Isometric tension–pCa relations. (a) Isometric tension–pCa relations obtained in Triton-skinned left ventricular fibers from young rats (3 months old; control, n = 23 fibers; lipopolysaccharide (LPS) 0.5 mg/kg, n = 23; and LPS 5 mg/kg, n = 22) treated with LPS or saline (control). (b) Isometric tension–pCa relations in Triton-skinned left ventricular fibers from senescent rats (24 months old; control, n = 22 fibers; LPS 0.5 mg/kg, n = 20). Curves of fibers from LPS-treated (0.5 and 5 mg/kg) animals were shifted toward lower pCa values only in young rats, indicating a decrease in Ca²⁺ sensitivity of the contractile proteins. Values are the mean ± standard error of the mean.