Fig. 6.

Effects of lipopolysaccharide (LPS) on sleep-wake behavior are exacerbated in C57BL/6J mice previously inoculated with murine gamma herpes virus 68 (γHV68). Thirty days after intranasal inoculation with γHV68 (400 pfu: n = 13; 40,000 pfu: n = 8), mice were injected intraperitoneally with pyrogen-free saline as detailed in protocol Fig. 1 and in the methods section. Recordings were obtained for 24 h after these control injections, and are triple plotted (open symbols). These same animals were then injected intraperitoneally with 10 µg LPS and recordings continued for 5 days (closed symbols). A separate group of animals (n = 6) that had not been inoculated with γHV68 (ie., uninfected) were injected intraperitoneally with pyrogen-free saline and control recordings obtained (open symbols). These control animals were then injected with LPS, as in the other groups (closed symbols). On this figure, values are plotted for the first 60 h after injection of LPS. All values are hourly means (±SEM). Black bars on the x-axis denote the dark portion of the light: dark cycle. Horizontal lines with asterisks indicate statistically significant differences between control and experimental values (p < 0.05).