Piccione Giuseppe, Caola Giovanni, Refinetti Roberto
Dipartimento di Morfologia, Biochimica, Fisiologia e Produzioni Animali, Facoltà di Medicina Veterinaria, Università degli Studi di Messina, Messina, Italy.
Chronobiol Int. 2004 Jul;21(4-5):571-89. doi: 10.1081/cbi-200026447.
The homeostatic control of physiological processes is affected by a variety of temporal programs, such as circadian rhythms, estrous cycles, and circannual rhythms. The existence of circaseptan rhythms (endogenous rhythms with the duration of a week) has been postulated but not properly verified. In this study, we compared plasma concentration of lactic acid, systolic and diastolic blood pressure, and rectal temperature in athletic horses (maintained under a weekly training schedule) with those in sedentary horses (maintained under a constant schedule throughout the week). Although exercise had robust acute effects on the measured parameters, measurements conducted early in the morning or in the evening showed significant weekly rhythmicity only in one of the parameters (plasma concentration of lactic acid) in a few animals. This rhythmicity was feeble, was present only in athletic horses, and vanished if rigorous statistical criteria were applied. In contrast, 24 h rhythmicity was significant in all parameters in all horses. We conclude that the overall 7-day pattern in physiological parameters of the horse is feeble and is caused by the weekly schedule of activity. The available evidence does not support the notion of endogenous, circaseptan rhythms.
生理过程的稳态控制受多种时间程序的影响，如昼夜节律、发情周期和年周期节律。七日节律（持续时间为一周的内源性节律）的存在已被推测，但尚未得到充分验证。在本研究中，我们比较了运动马（按照每周训练计划饲养）和久坐马（整周按照固定计划饲养）的血浆乳酸浓度、收缩压和舒张压以及直肠温度。尽管运动对所测参数有强烈的急性影响，但仅在少数动物的一个参数（血浆乳酸浓度）中，清晨或傍晚进行的测量显示出显著的每周节律性。这种节律性很微弱，仅存在于运动马中，并且如果应用严格的统计标准就会消失。相比之下，所有马匹的所有参数中24小时节律性都很显著。我们得出结论，马的生理参数的整体7天模式很微弱，是由每周的活动计划引起的。现有证据不支持内源性七日节律的观点。
