Differences between August and Wistar rats in stress reactions and in the development of adaptation to stress

Abstract

Control and acutely stressed August rats have corticosterone levels 62% and 15% higher, respectively, than their Wistar counterparts, indicating that the activity of stress-mediating hypothalamic-pituitary-adrenal system in August rats is higher. On the other hand, the intensity of stress reactions and, consequently, the degree of activation of this system in August rats are 40-50% lower, as is the blood level of creatine phosphokinase. During adaptation to stress, August and Wistar rats show a similar decrease in the stress reaction and in its damaging effects. However, judging from the blood corticosterone/insulin ratio, adaptation to stress in August rats coincides with intensification of catabolic processes and a reduction in the efficiency of energy production.

Differences in behavioral patterns and resistance to stress-induced gastric ulceration between August and Wistar rats adapted and unadapted to hypoxia

“…Thus, August rats were more resistant to stress than Wistar rats. These results are consistent with previously reported data showing that stress induced a less pronounced rise in blood creatine phosphokinase in August rats compared to Wistar rats [8].…”

“…It should be emphasized that August and Wistar rats have various basal and poststress activities of the hypothalamo-pituitary-adrenocortical system and, therefore, different blood concentrations of glucocorticoids preventing stress-induced ulceration [1]. It was shown that basal and poststress contents of glucocorticoids in the blood of August rats are much higher than in Wistar rats [8,13].…”

“…However, in stressed August rats the rise in blood concentration of creatine phosphokinase (marker of injuries) is less pronounced [8], and the primary immune response to sheep erythrocytes was greater than in stressed Wistar rats [11]. Therefore, various systems of the body have different genetically determined resistances to stress-induced damages.…”

Resistance to Neurodegenerative Brain Damage in August and Wistar Rats

“…Stress exposure induces a weaker stress response in August rats, which is accompanied by less severe damage (compared to Wistar rats) [6]. In August rats, activity of the stress-limiting system that decreases the stress response and attenuates stress-induced changes is higher than in Wistar rats [7,4].…”