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This Article Full Text Full Text (PDF) Erratum (v586,p1777) All Versions of this Article: 586/2/639    most recent jphysiol.2007.143180v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burgess, H. J. Articles by Eastman, C. I. Search for Related Content PubMed PubMed Citation Articles by Burgess, H. J. Articles by Eastman, C. I. Related Collections Renal and Endocrine

¹ Biological Rhythms Research Laboratory, Department of Behavioural Sciences, Rush University Medical Center, Chicago, IL, USA
² Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK

Exogenous melatonin is increasingly used for its phase shifting and soporific effects. We generated a three pulse phase response curve (PRC) to exogenous melatonin (3 mg) by administering it to free-running subjects. Young healthy subjects (n = 27) participated in two 5 day laboratory sessions, each preceded by at least a week of habitual, but fixed sleep. Each 5 day laboratory session started and ended with a phase assessment to measure the circadian rhythm of endogenous melatonin in dim light using 30 min saliva samples. In between were three days in an ultradian dim light (< 150 lux)–dark cycle (LD 2.5 : 1.5) during which each subject took one pill per day at the same clock time (3 mg melatonin or placebo, double blind, counterbalanced). Each individual's phase shift to exogenous melatonin was corrected by subtracting their phase shift to placebo (a free-run). The resulting PRC has a phase advance portion peaking about 5 h before the dim light melatonin onset, in the afternoon. The phase delay portion peaks about 11 h after the dim light melatonin onset, shortly after the usual time of morning awakening. A dead zone of minimal phase shifts occurred around the first half of habitual sleep. The fitted maximum advance and delay shifts were 1.8 h and 1.3 h, respectively. This new PRC will aid in determining the optimal time to administer exogenous melatonin to achieve desired phase shifts and demonstrates that using exogenous melatonin as a sleep aid at night has minimal phase shifting effects.

(Received 16 August 2007; accepted after revision 9 November 2007; first published online 15 November 2007)
Corresponding author H. J. Burgess: Biological Rhythms Research Laboratory, Rush University Medical Center, 1645 W. Jackson Blvd, Suite 425, Chicago, IL 60612, USA. Email: helen_j_burgess{at}rush.edu

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				Erratum J. Physiol., March 15, 2008; 586(6): 1777 - 1777. [Full Text] [PDF]