The effects of Valerian on sleep spindles in a model of neuropathic pain

Introduction: Valeriana officinalis is known to be one of the most famous herbal supplements for the treatment of anxiety and insomnia. Despite its widespread use in most countries all around the world, there is little scientific information and research on how this medication affects sleep patterns, and there are almost no studies on its effects on the characteristics of sleep spindles. Material and Methods: The present study was conducted to investigate the effects of Valerian extract (VAL) on sleep spindles and induced anxiety in chronic neuropathic pain model in rats. 24 male rats were divided into three groups: neuropathic group (n=9) in which the rats underwent chronic constriction injury (CCI), sham group (n=7) in which the sciatic nerves of the animals were exposed without any constriction and also fed with the vehicle, and the third group was under CCI condition and treated with Valerian (n=8). All the rats underwent electrode implant surgery so that we could record electroencephalogram and electromyography waves. In all the three groups, EEG and EMG recordings were recorded three times (150min each time). The initial recording was just prior to the CCI surgery and the rest were 3 and 6 days following CCI surgery. Moreover, cold allodynia and elevated plus maze tests were performed 3 and 6 days following the CCI surgery. Results: Valerian treatment could repair the allodynia induced by neuropathy. On the other hand, by Valerian treatment (400mg/kg) during neuropathy, the REM sleep, decreased and the non-REM sleep increased. Moreover, there was an increment in sleep spindle density and spindle frequency even in neuropathic condition. Discussion: This herbal supplement improves the quality of sleep in neuropathy conditions.