%0 Journal Article
%T "Time sweet time": circadian characterization of galectin-1 null mice
%A Leandro P Casiraghi
%A Diego O Croci
%A Francoise Poirier
%A Gabriel A Rabinovich
%A Diego A Golombek
%J Journal of Circadian Rhythms
%D 2010
%I BioMed Central
%R 10.1186/1740-3391-8-4
%X We analyzed wheel-running activity in light-dark conditions, constant darkness, phase responses to light pulses (LP) at circadian time 15, and reentrainment to 6 hour shifts in light-dark schedule in wild-type (WT) and Lgals1-/- mice.We found significant differences in free-running period, which was longer in mutant than in WT mice (24.02 vs 23.57 h, p < 0.005), phase delays in response to LP (2.92 vs 1.90 circadian h, p < 0.05), and also in alpha (14.88 vs. 12.35 circadian h, p < 0.05).Given the effect of a null mutation on circadian period and entrainment, we indicate that galectin-1 could be involved in the regulation of murine circadian rhythmicity. This is the first study implicating galectin-1 in the mammalian circadian system.Circadian systems represent an endogenous mechanism adapted to cycling environmental conditions. In mammals, the central circadian clock is located in the suprachiasmatic nuclei (SCN), guiding circadian-regulated biological variables such as the sleep-wake cycle, hormonal secretions and locomotor activity [1]. Another physiological process that exhibits circadian fluctuations, with obvious implications in disease progression and outcome, is the regulation of immune function.The link between the circadian and the immune systems has been extensively investigated [2-4]. Circadian rhythms within the immune system were described in several tissues and cellular populations [5]. In humans, the number of lymphocytes and granulocytes peaks during the night, whereas monocytes and neutrophil levels fall during the day [6]. Major humoral immune responses undergo circadian changes, and rhythms in plasmatic levels of pro-inflammatory cytokines, as well as peptide hormones produced and secreted by immune cells, were also reported [3,5-7].In addition, circadian outputs might affect the central clock through a feedback mechanism that fine-tunes the system. The influence of the immune over the circadian system has been studied in recent years, and there a
%U http://www.jcircadianrhythms.com/content/8/1/4