Figure 7.

Atrial-specific Tnf gene ablation blunts downstream TNF-mediated signal transduction but not mechanical stress with swim exercise. (A) Evidence of profound and sustained swim-induced elevations in left ventricular end-diastolic pressures (LVEDPs), an index of left atrial pressures and a stimulus for mechanical stretch, derived from telemetric haemodynamic recordings. No differences in acute (30 min) exercise-induced LVEDPs were observed between Nppa-Cre+ and Cre− mice. Exercise commenced at time = 10 min, as indicated by the black arrow. (B) Western blotting analysis revealed increased p38 phosphorylation in the atria (compared to total p38) following 30 min of swim exercise in Cre− mice (n = 6 per group) compared to sedentary (non-swim) mice. Increases in p38 phosphorylation in response to acute swim were blunted in Nppa-Cre+ mice (n = 7 per group), but not Tie2-Cre+ mice (n = 6). Data are normalized relative to Cre− sedentary mice and presented as mean ± S.e.m. Full western blots can be found in the Supplementary material online, Supplementary Materials. P values from repeated measures or non-repeated measures two-way ANOVA with Sidak’s multiple comparison tests. *P < 0.05. NS, not significant.