Plasma catecholamine and corticosterone responses to predictable and unpredictable noise stress in rats

Abstract

Plasma noradrenaline (NA), adrenaline (A) and corticosterone (CS) increases were determined in individual rats subjected to either 20 regularly or irregularly scheduled white-noise stimulations (4 min, 100 dBA). Blood was frequently sampled during the first and twentieth noise exposure, and during a reexposure after 24 hr. During the sampling periods, behavioral activities of the rats were recorded. The initial noise-induced CS release was partially reduced following the regular noise presentations. The increase after irregular presentations remained high. The difference in adrenocortical responsiveness between regular and irregular exposure persisted for 24 hr. The NA response to noise was partially attenuated following irregular administration of noise. However, regular exposure produced increased NA levels prior to noise presentation and a subsequent decrease during stimulation. After 24 hr, noise evoked an exaggerated initial NA release in the regular group. The noise-elicited rise in A was completely abolished after 20 noise presentations irrespective of whether these were applied regularly or irregularly. Reexposure after 24 hr evoked again a significant A response in both groups. No differences were observed in the habituation pattern of behavioral reactions among the regular and irregular groups. The results show that the sympathetic neural, adrenomedullary and adrenocortical systems differ in degree and speed of adaptation to intermittent stressful stimuli and in sensitivity to the predictability of stressors.

Differential effects of chronic predictable and unpredictable stress on neurobehavioral and biochemical responses in rats

“…Our findings are in general agreement with an earlier study of de Boer et al [25] , where it was reported that following chronic predictable noise stress the corticosterone levels came to a stable level as compared to chronic unpredictable noise stress in rats. However our results differ from those of Fabiola et al [26] who reported more pronounced impairments after repeated restraint stress as compared to that seen after variable stress.…”

Comparison of the effects of acute and chronic psychological stress on metabolic features in rats

“…However, by increasing the days of exposure to stress the catecholamines' response may be adapted and therefore may cause the plasma glucose level on Day 30 not to change significantly (de Boer et al, 1990). It is noteworthy that the patterns of corticosterone and catecholamine of sympathoadrenal response and adaptation to intermittent stress are different (de Boer et al, 1989).…”

Immunomodulatory Effect of Triphala during Experimentally Induced Noise Stress in Albino Rats

“…1) Noise-stress was selected, since it has a high environmental and clinical relevance and appears to be a mild stressor with respect to neuroendocrine activation. 10) To determine the best potential impact of Triphala intake on an immune response, the highly immunogenic, non-infectious SRBC used as a stimulating agent in Values are expressed as mean ± S.D. of six animals.…”