H1N1 infection of sleep/wake regions results in narcolepsy-like symptoms

Introduction

Narcolepsy is a debilitating, neurological sleep disorder that is characterized by excessive daytime sleepiness and nighttime sleep disturbance. In narcolepsy type 1, the loss of arousal state boundary control can lead to cataplexy—the sudden loss of muscle tone triggered by strong emotions—and intrusions of rapid eye movement (REM) sleep at abnormal times. Cataplexy resembles the muscle atonia observed during REM sleep and is pathognomonic of the disease. The neurological basis for narcolepsy resides in the degeneration of the hypothalamic neurons that produce the neuropeptide hypocretin (HCRT, also known as orexin), but how and why these specific cells die is one of the most important, unanswered questions in the field. Although certain genetic predispositions increase the risk for narcolepsy, low concordance rates between twins suggest that environmental factors (e.g., exposure to infectious agents) play an important role in initiating disease onset. Tesoriero et al. (1) use an innovative means of manipulating the immune system of the mouse to examine whether viral infection can impact HCRT neurons and other cell groups responsible for arousal state control.