Effects of acute microwave irradiation on phenobarbital sleep and disposition to brain in mice

Following a 10‐min near‐field exposure to sham radiation of 2.45 GHz microwave (MW) radiation at a power density of 10 mW/cm2, male Swiss‐Cox mice were injected with sodium phenobarbital (PB) (150 mg/kg, iv) and the onset and duration of PB‐induced sleep were recorded. MW‐pretreated mice exhibited a decreased PB sleep onset relative to sham when PB was administered 1 to 45 min following irradiation; however, no effect was seen by 24 h. The duration of PB‐induced sleep was increased; however MW pretreatment did not affect the duration of hexobarbital‐ or pento‐barbital‐induced sleep. At the time of onset of PB‐induced sleep, PB concentrations in brain of MW‐irradiated and control groups were the same despite a twofold difference in the time to sleep onset between these groups. But, when measured 5 min following PB injection, the PB concentrations in brain were higher in MW‐pretreated mice, suggesting that a dispositional mechanism accounted for the observed MW effects on PB‐induced sleep. Mice heated for 1...