TNF and serum lipopolysaccharide activity: TNF production through spleen macrophages in the red pulp and the marginal zone was specifically attenuated with the electrical stimulation of the vagus nerve in male Sprague–Dawley rats and nicotine (2 mg/kg, i.p.)treatment in the LPS-induced endotoxemia model of male BALB/C mice during endotoxemia (15).