Article Figures & Data
Figures
- Fig. 1.
Male Sprague Dawley rats (8 in each group) were killed by focused microwave irradiation at three power levels (3.5, 6.0, or 10 kW) or by decapitation (Decap.). Irradiation times were adjusted for brains to be heated to 82 ± 3°C. Glycogen levels were determined for the frontal cortex (A) and hypothalamus (B). Values illustrated are mean ± SEM values. Glycogen levels in the frontal cortex and hypothalamus of rats killed with 6.0 and 10 kW of microwave power were significantly (p < 0.001) higher than were levels in rats killed with 3.5 kW of microwave power or by decapitation. Glycogen levels in the frontal cortex of rats killed with 10 kW of microwave power were significantly (p < 0.05) higher than were levels in rats killed with 6.0 kW of microwave power.
- Fig. 2.
A, Male Sprague Dawley rats were deprived of sleep starting at 6:00 A.M. (lights on) for 6, 12, or 24 hr and then killed by 10 kW of focused microwave irradiation. Glycogen levels were measured in the brain minus the cerebellum and brainstem of control (Ctrl.) and sleep-deprived (SD) rats. Mean ± SEM values from eight rats in each group are shown. Glycogen levels in control animals showed no statistically significant differences between the separate 6, 12, and 24 hr studies. Statistically significant decreases in brain glycogen levels were observed with sleep-deprivation periods of 12 (p < 0.01) and 24 (p < 0.001) hr. B, Two separate groups of male Sprague Dawley rats were deprived of sleep for 12 hr starting at 6:00 A.M. Rats in group 1 were killed by 10 kW of focused microwave irradiation after 12 hr of sleep deprivation. Rats in group 2 were allowed recovery (Rec.) sleep in an isolated room for 15 hr before being killed by 10 kW of focused microwave irradiation. Glycogen levels were measured in the brain minus the cerebellum and brainstem, and data shown are mean ± SEM values from eight animals in each group. Statistically significant (p < 0.01) decreases in glycogen levels were observed with 12 hr of sleep deprivation compared with control animals, whereas statistically significant (p < 0.05) increases in glycogen levels were observed with 15 hr of recovery sleep after the 12 hr sleep-deprivation period.
- Fig. 3.
Histochemical determination of brain glycogen. Control rats (A, C, E) and rats deprived of sleep for 12 hr (B, D, F) were killed either by intracardial perfusion of 4% paraformaldehyde (A, B, E–G) or by 10 kW of microwave irradiation (C, D). For rats that were perfusion-fixed, brain sections were either cut using a cryostat (C–G) or paraffin-embedded and cut using a microtome (RM2125RT; Leica, Nussloch, Germany) (A, B). Regardless of method used to kill the animal and cut the tissue sections, all sections were processed and stained the same for PAS–dimedone histochemistry. G, Pretreatment of sections with diastase to digest glycogen yielded background staining from nonglycogen sources. H, Images were digitized and staining intensities were measured with Scion software. Each group consisted of four rats. Values are mean ± SEM from eight separate sections per animal (*p < 0.05; **p < 0.01).
- Fig. 4.
Codistribution of brain glycogen and astrocytes.A, Glycogen is enriched in white matter. Brain regions were dissected from rats killed by 10 kW of focused microwave irradiation. Levels of glycogen in the corpus callosum (white matter) were significantly higher (p < 0.001) than levels in the other brain regions examined. Mean ± SEM values from eight rats in each group are shown. B, Double-labeling of brain sections with antibodies against GFAP and NFL revealed that astrocytes were distributed throughout the brain but were concentrated in white matter.
- Fig. 5.
Histochemical determination of brain glycogen in control (Ctrl) rats (A), rats that were deprived of sleep (SD) for 12 hr (B), and rats that were deprived of sleep for 12 hr followed by 15 hr of recovery (Rec.) sleep (C). All rats were perfusion-fixed, and brain sections were cut using a cryostat. Images were digitized, staining intensities were measured with Scion, and values shown are mean ± SEM from four rats (p < 0.01 compared with control values).
Tables
- Table 1.
Effect of starvation on brain glycogen (micromoles per gram of wet weight tissue)
Brain region Control Starvation Striatum 3.1 ± 0.2 3.5 ± 0.2 Cortex 3.6 ± 0.2 4.2 ± 1.2 Thalamus 3.2 ± 0.2 2.7 ± 0.3 Brain Stem 4.0 ± 1.0 4.1 ± 0.3 Cerebellum 3.2 ± 0.4 4.0 ± 0.1 Brain levels of glycogen were not affected by starvation. Male Sprague Dawley rats were starved for 12 hr starting at 6:00 P.M. (lights out) and killed at 6:00 A.M. by 10 kW of focused microwave irradiation. Glycogen levels were measured in isolated brain regions and data are mean ± SEM values from four animals in each group.
