Fig. 6.
Rapid return of c-fos mRNA levels after arousal. Autoradiographs of Northern blots of total RNA (20 μg/lane) isolated from hypothalamus of ground squirrels killed during different phases of the hibernation cycle as in Figure 3, with the addition of several well defined postarousal time points and one additional entrance time point (N30). N30 is early entrance to torpor (Tb of 30°C), and N20 is midentrance (Tb of 20°C), the same as EN in other figures. Note the increasing amount of c-fos mRNA during torpor and the high peak during arousal as in Figure 3, and then the rapid return to basal levels after arousal. Levels of c-fos mRNA during arousal are significantly elevated over all other phases; *p < 0.01. n = 3 for each condition. Other abbreviations as in Figures 3-5.