Survival of LPS endotoxic shock is improved in Tph1^−/− mice. (A) Kaplan-Meier survival analysis after intraperitoneal injection of E coli serotype 055:B5 LPS into male mice (n = 14). (B) Survival after intraperitoneally injection of E coli 0111:B4 LPS (n = 12). (C) Serum TNFα levels at the indicated time points after E coli 055:B5 LPS injection (n = 3). Heart rate (D) and heart rate variability (E) were measured noninvasively in awake mice at the depicted time points after E coli 055:B5 LPS challenge (n = 6).