tailieunhanh - Báo cáo y học: "Preliminary evidence for a change in spectral sensitivity of the circadian system at night"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Preliminary evidence for a change in spectral sensitivity of the circadian system at night. | Journal of Circadian Rhythms BioMed Central Research Open Access Preliminary evidence for a change in spectral sensitivity of the circadian system at night Mariana G Figueiro1 John D Bullough1 Robert H Parsons2 and Mark S Rea 1 Address lighting Research Center Rensselaer Polytechnic Institute 21 Union Street Troy NY 12180 USA and 2Department of Biology Rensselaer Polytechnic Institute 110 8th Street Troy NY 12180 USA Email Mariana G Figueiro - figuem@ John D Bullough - bulloj@ Robert H Parsons - parsor@ Mark S Rea - ream@ Corresponding author Published II December 2005 Received 03 October 2005 Accepted 1 1 December 2005 Journal of Circadian Rhythms 2005 3 14 doi 1740-3391-3-14 This article is available from http content 3 1 14 2005 Figueiro et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background It is well established that the absolute sensitivity of the suprachiasmatic nucleus to photic stimulation received through the retino-hypothalamic tract changes throughout the 24-hour day. It is also believed that a combination of classical photoreceptors rods and cones and melanopsin-containing retinal ganglion cells participate in circadian phototransduction with a spectral sensitivity peaking between 440 and 500 nm. It is still unknown however whether the spectral sensitivity of the circadian system also changes throughout the solar day. Reported here is a new study that was designed to determine whether the spectral sensitivity of the circadian retinal phototransduction mechanism measured through melatonin suppression and iris constriction varies at night. Methods Human adult males were exposed to a high-pressure mercury lamp 450 lux 170 jW cm2 at .