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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments were conducted on rats to study the dynamics of changes of the heart contractile function (CF) and some indices of myocardial energy metabolism during adaptation to moderate continuous 15-day stress. After 24 hours of stress a complex of shifts typical of an acute stress syndrome (mobilization of CF, reduction of the content of glycogen and creatine phosphate, increase of phosphorylase activity) was recorded. After 5 days of stress the absolute CF value reduced, particularly at rest (doubled), as a consequence of which the relative values of the maximally developing CF on the 5th second of an isometric load induced by compression of the aorta were 1.5 times those in the controls. The content of glycogen and creatine phosphate and the activity of phosphorylase were reduced by 25-30%. After 15 days the CF and the values of myocardial energy metabolism were normalized. Exclusion of the vagal tonus by atropine on the 5th day of stress showed that the low level of CF and reduced phosphorylase activity are not consequent upon heart exhaustion but are regulatory mechanisms.
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PMID:[Contractile function and some parameters of energy metabolism of the myocardium in the process of adaptation to the effect of moderate continuous stress]. 188 2

Two-year-old whitefish (Coregonus lavaretus) were exposed for 30 days to episodic iron overload in iron-rich humic water (5%) supplemented with inorganic iron (5 mg FeL(-1)). Two parallel laboratory exposures were performed, one under conditions simulating winter and the other under conditions simulating spring. After exposure, some of the fish were subjected to acute handling stress in the form of a short air challenge to reveal possible modification of the primary and secondary stress responses. In whitefish sampled without additional handling, iron accumulated in the liver (under spring conditions) and gills (under winter and spring conditions); plasma catecholamine and beta-estradiol (both winter and spring groups) as well as blood hematocrit (winter group only) levels were depressed; blood glucose (winter group only) and red blood cell (RBC) Na+ levels (spring group only) were increased. In handled whitefish, liver glycogen phosphorylase (GPase), RBC, and blood glucose stress responses were impaired by the applied exposure conditions, which reflected natural iron-rich humic water. Exposure also removed some physiological effects of the applied ambient conditions: plasma catecholamines and beta-estradiol, gill Na+/K+ -ATPase, and RBC K+ concentration were not different in two iron-exposed fish groups, whereas there was a difference in reference fish. Thus, the physiological effects of this type of subchronic exposure, together with alterations in the acute stress response, can lead to incorrect conclusions being drawn from the results, if the effects of time-dependent stress response are ignored. In conclusion, waterborne iron overload may impair the optimal capacity of whitefish to carry out their normal physiological functions such as responding to external threats.
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PMID:Effects of waterborne iron overload and simulated winter conditions on acute physiological stress response of whitefish, Coregonus lavaretus. 1554 31