Temporal relationship between daily pain and actigraphy sleep patterns in pediatric sickle cell disease.

Limited research is available on the relationship between objective sleep patterns and pain in children with SCD. Research in other chronic pain populations suggests that the effect of sleep disruption on pain may be stronger than the effect of pain on sleep that night. To examine the bi-directional relationship between objective sleep patterns and daily pain in a pediatric SCD sample. Participants were 30 African American children with SCD 8-18 years (13 ± 2.8 years; 66.7% female) with frequent pain. Children and parents completed questionnaires to assess pain, medications, and depression/anxiety. Over a 14-day period, children completed a pain diary and ambulatory actigraphy monitoring to assess nighttime sleep (duration, efficiency and WASO). Greater pain severity was associated with worse sleep efficiency and greater WASO that night, controlling for age, sex, opioid medication, and depression/anxiety symptoms. Worse sleep efficiency was associated with the occurrence of pain and more severe pain the next day. There was no relationship between WASO and pain. Similarly, sleep duration did not influence pain. Results lend support for a bi-directional relationship between sleep parameters and daily pain in pediatric SCD, and identify sleep as a potential target for future research and intervention.

Comparative effects of Mitragyna speciosa extract, mitragynine, and opioid agonists on thermal nociception in rats.

This study sought to compare the effects of Mitragyna speciosa (Korth.) Havil. extract, alkaloids fraction, and mitragynine, a µ-opioid receptor agonist, to that of morphine and oxycodone in a test of thermal nociception. In Experiment 1, male Sprague-Dawley rats were administered test articles intraperitoneally (IP) 30 min prior to testing to compare the effects of M. speciosa articles to opioid reference compounds on the hotplate assay. Test articles were vehicle, 10 mg/kg morphine, 3 mg/kg oxycodone, 300 mg/kg M. speciosa extract, 75 mg/kg M. speciosa alkaloids fraction, or 30 mg/kg mitragynine. To mirror consumer usage, Experiment 2 sought to determine whether M. speciosa articles retained their biological activity when given orally (PO). Test articles were vehicle, 6 mg/kg oxycodone, 300 mg/kg M. speciosa extract, or 100mg/kg mitragynine with hotplate tests conducted 30 and 60 min after administration. Mitragynine produced antinociceptive effects similar to the reference opioid agonists when administered IP and PO routes. These data suggest that M. speciosa extracts containing significant quantities of mitragynine may warrant consideration for further studies in primate self-administration models to yield insight into the abuse liability of this commercially available product.