A Rodent Model of Traumatic Stress Induces Lasting Sleep and Quantitative Electroencephalographic Disturbances

Hyperarousal and sleep disturbances are common, debilitating symptoms of post-traumatic stress disorder (PTSD). PTSD patients also exhibit abnormalities in quantitative electroencephalography (qEEG) power spectra during wake as well as rapid eye movement (REM) and non-REM (NREM) sleep. Selective serotonin reuptake inhibitors (SSR1s), the first-line pharmacological treatment for PTSD, provide modest remediation of the hyperarousal symptoms in PTSD patients, but have little to no effect on the sleep wake architecture deficits. Development of novel therapeutics for these sleep wake architecture deficits is limited by a lack of relevant animal models. Thus, the present study investigated whether single prolonged stress (SPS), a rodent model of traumatic stress, induces PTSD-like sleep wake and qEEG spectral power abnormalities that correlate with changes in central serotonin (5-HT) and neuropeptide Y (NPY) signaling in rats. Rats were implanted with telemetric recording devices to continuously measure EEG before and after SPS treatment. A second cohort of rats was used to measure SPS-induced changes in plasma corticosterone, 5-HT utilization, and NPY expression in brain regions that comprise the neural fear circuitry. SPS caused sustained dysregulation of NREM and REM sleep, accompanied by state-dependent alterations in qEEG power spectra indicative of cortical hyperarousal. These changes corresponded with acute induction of the corticosterone receptor co-chaperone FK506-binding protein 51 and delayed reductions in 5-HT utilization and NPY expression in the amygdala. SPS represents a preclinical model of PTSD-related sleep wake and qEEG disturbances with underlying alterations in neurotransmitter systems known to modulate both sleep wake architecture and the neural fear circuitry.