NAN-190 potentiates the circadian response to light and speeds re-entrainment to advanced light cycles

Health problems can arise from de-synchrony between the external environment and the endogenous circadian rhythm, yet the circadian system is not able to quickly adjust to large, abrupt changes in the external daily cycle. In this study, we investigated the ability of NAN-190 to potentiate the circadian rhythm response to light as measured by phase of behavioral activity rhythms. NAN-190 (5 mg/kg, i.p.) was able to significantly potentiate the response to light both in dark-adapted and entrained hamsters. Furthermore, NAN-190 was effective even when administered up to 6 h after light onset. Response to a light pulse was both greater in magnitude and involved fewer unstable transient cycles. Finally, NAN-190 was able to speed re-entrainment to a 6 h advance of the light/dark cycle by an average of 6 days when compared with vehicle-treated animals. This work suggests that compounds like NAN-190 may hold great potential as a pharmaceutical treatment for jetlag, shift work, and other circadian disorders. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.