Abstract
BackgroundAdenosine 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.MethodsAdult 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.ResultsAll stressed groups showed significant decreases in all enzyme activities at ZT 12 and ZT 18 when compared with control.ConclusionAcute 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.
Highlights
Adenosine 5-triphosphate (ATP) and its breakdown products adenosine 5’-diphosphate (ADP) and adenosine can act as extracellular messengers in a range of biological processes
Previous work by our group demonstrated that ATPase and ADPase activities exhibit a 24-hour temporal pattern in rat blood serum, with activities increased during the dark period while AMPase activity did not display circadian variation [7]
Considering that the temporal variation of nucleotidase activities [7] may be of great importance in regulating the cardiovascular system, and that acute stress disrupts both circadian rhythms [15,16] and the function of the cardiovascular system [17], we investigated the effects of acute restraint stress on the 24-h temporal pattern of ATPase, ADPase and AMPase enzyme activities in rat blood serum
Summary
Adenosine 5-triphosphate (ATP) and its breakdown products ADP and adenosine can act as extracellular messengers in a range of biological processes. Extracellular adenosine 5’-triphosphate (ATP) and its breakdown products, adenosine 5’-diphosphate (ADP), adenosine 5’-monophosphate (AMP) and adenosine, can act as extracellular messengers in a range of biological processes through binding to purinergic receptors. They have been shown to have pronounced effects on a variety of biological processes such as neurotransmission, regulation of cardiac function and platelet aggregation [1], as well as pathological events including. The ecto-5’-nucleotidase is attached to the cell surface and may occur in a soluble form via cleavage of its glycosyl-phosphatidylinositol (GPI)-anchor by phospholipase C [6] These nucleotidases, together with 5’-nucleotidase, control the availability of ligands (ATP, ADP and adenosine) for both nucleotide and nucleoside receptors, and the duration and extent of receptor activation [4]. Previous work by our group demonstrated that ATPase and ADPase activities exhibit a 24-hour temporal pattern in rat blood serum, with activities increased during the dark period while AMPase activity did not display circadian variation [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
