Figure 6.

Adenosine mediates injury tolerance after preconditioning. A, Adenosine concentration detected by an adenosine biosensor in the medium of C6–Cx43⁺ and C6–Cx43⁻ cells after exposure to vehicle or preconditioning (PC) stimulation. Data represent average ± SE (n = 5–6). **p < 0.0001, t test. B, MRS1754, an antagonist of adenosine A_2b receptors, attenuated injury tolerance after preconditioning. Data represent average ± SE (n = 12). **p < 0.01, Tukey–Kramer test. C, An array of P₂ receptors antagonist {suramin, reactive blue (RB), PPADS, and MRS2179} and A_1–2 receptor antagonist (caffeine, DPCPX) had no impact on the protection afforded by preconditioning. Data represent average ± SE (n = 3–22). *p < 0.05, **p < 0.01, Tukey–Kramer test.