Souza Andressa, Detanico Bernardo C, Medeiros Liciane F, Rozisky Joanna R, Caumo Wolnei, Hidalgo Maria Paz L, Battastini Ana Maria O, Torres Iraci Ls
Laboratório de Cronobiologia Experimental, Departamento de Farmacologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170, Brazil.
J Circadian Rhythms. 2011 Jul 28;9:7. doi: 10.1186/1740-3391-9-7.
Adenosine 5-triphosphate (ATP) and its breakdown products ADP and adenosine can act as extracellular messengers in a range of biological processes. Extracellular adenine nucleotides are metabolized by a number of enzymes including NTPDases and 5'-nucleotidase, which are considered to be the major regulators of purinergic signaling in the blood. Previous work by our group demonstrated that ATPase and ADPase activities in rat serum exhibit a 24-h temporal pattern, with higher enzyme activity during the dark (activity) phase. It was found that stress can cause disruptions in biological circadian rhythms and in the cardiovascular system. Therefore, the aim of the present study was to examine the influence of acute stress exposure upon temporal patterns of NTPDase and 5-nucleotidase enzyme activities in rat blood serum.
Adult male Wistar rats were divided into 4 groups: ZT0, ZT6, ZT12 and ZT18. Each group was subdivided in 4 groups: control, immediately, 6 h and 24 h after one hour of restraint stress. ATP, ADP and AMP hydrolysis were assayed in the serum.
All stressed groups showed significant decreases in all enzyme activities at ZT 12 and ZT 18 when compared with control.
Acute stress provokes a decrease in nucleotidase activities dependent on the time that this stress occurs and this effect appears to persist for at least 24 hours. Stress can change levels of nucleotides, related to increased frequency of cardiovascular events during the activity phase. Altered levels of nucleotides in serum may be involved in cardiovascular events more frequent during the activity phase in mammals, and with their etiology linked to stress.
三磷酸腺苷（ATP）及其分解产物二磷酸腺苷（ADP）和腺苷可在一系列生物过程中充当细胞外信使。细胞外腺嘌呤核苷酸由多种酶代谢，包括NTPD酶和5'-核苷酸酶，它们被认为是血液中嘌呤能信号传导的主要调节因子。我们小组之前的研究表明，大鼠血清中的ATP酶和ADP酶活性呈现24小时的时间模式，在黑暗（活动）阶段酶活性较高。研究发现，应激会导致生物昼夜节律和心血管系统紊乱。因此，本研究的目的是探讨急性应激暴露对大鼠血清中NTPD酶和5'-核苷酸酶活性时间模式的影响。
成年雄性Wistar大鼠分为4组：ZT0、ZT6、ZT12和ZT18。每组再细分为4组：对照组、束缚应激1小时后即刻、6小时和24小时组。测定血清中ATP、ADP和AMP的水解情况。
与对照组相比，所有应激组在ZT12和ZT18时所有酶活性均显著降低。
急性应激会导致核苷酸酶活性降低，这取决于应激发生的时间，且这种影响似乎至少持续24小时。应激会改变核苷酸水平，这与活动阶段心血管事件频率增加有关。血清中核苷酸水平的改变可能与哺乳动物活动阶段更频繁的心血管事件有关，且其病因与应激有关。
