Fig. 1.

Vagus nerve stimulation increases acetylcholine levels in the spleen and requires T lymphocytes to attenuate TNF-α in endotoxemia. (A) BALB/c mice (n = 5) were subjected to vagus nerve stimulation (5 min), and spleen acetylcholine levels were determined in dialysate samples by mass spectrometry. Results are expressed as a percentage of the average levels of three consecutive samples ± SEM obtained before vagus nerve stimulation (basal). P < 0.05 at 20 min compared with basal [repeated measures analysis of variance (ANOVA) and the Dunnett post hoc test]. VNS, vagus nerve stimulation. (B) Acetylcholine was measured by mass spectrometry in supernatants of nonadherent spleen cells in the presence or absence of norepinephrine at the indicated concentrations. Data were obtained from pooled cells stimulated in duplicate. Results are expressed as the mean of two experiments. *P < 0.05 compared with unstimulated cells (two-tailed t test). (C) BALB/c mice (four or five per group) and (D) BALB/c nude mice (five per group) were subjected to sham surgery or vagus nerve stimulation followed by endotoxin injection. Serum was obtained 90 min after endotoxin administration, and TNF-α was measured by enzyme-linked immunosorbent assay (ELISA). Results are means ± SEM. *P < 0.05 compared with the sham group (two-tailed t test).