Showing papers on "Social stress published in 1972"

Renal failure as the cause of death inTupaia belangeri exposed to persistent social stress

Abstract: 1. An adult male Tupaia belangeri was introduced to another male which was an experienced fighter. The latter immediately attacked the newcomer and subjugated him (Figs. 1 and 2). The two animals were subsequently separated, so that the subordinate animal could see the victor permanently, but could not be attacked by him. The fight and subjugation were repeated every 1-2 days, in order to maintain dominance relationships. Changes in physiological parameters were determined by sacrificing some of the tree-shrews at 2-16 days after the first subjugation, 80-100 minutes before the onset of daily activity. 2. After the first subjugation, subordinate animals lie still in a corner for more than 90 % of the daily activity-phase and follow the movements of the victors with their heads. The tail-hair is continuously raised, indicating persistent activation of the sympathetic nervous system. Subordinate animals eat as long as controls. 3. After 2-16 days, the skin-temperature of the subordinates abruptly falls from more than 35~ to less than 30~ within 24 hours. Cramps and paralysis appear in the extremities, the tree-shrews fall into coma and die. Wounds can be excluded as the cause of death. 4. The following physiological changes take place in the subordinate animals: a) The animals lose body weight in a linear fashion. The rate of weight-loss varies considerably between animals (Fig. 3). The more weight an animal loses daily, the more rapidly it dies (r ~ 0.89; Fig. 4). Death is not a result of inadequate energy-supply (resp. hypoglyeaemia). b) In subordinates, the glycogen content of the liver is significantly below that of controls (p~0.003; Table 1); but even dying animals may exhibit normal glycogen values. The glucose concentration of the blood is the same under both conditions (Table 1). c) The haemoglobin content of the blood decreases during stress exposure (r ~ 0.75; Fig. 5). The decrease is the more rapid, the more weight a subordinate animal loses daily (r~0.68). The decrease in haemoglobin concentration is primarily due to haemolysis, but erythropoiesis is also restricted (Table 2). d) The kidney weight decreases with continued stress; animals sacrificed more than 10 days after their first subjugation have kidneys approximately 17 % lighter than those of controls (p < 0.05; Fig. 8). e) During the course of stress, urea-N content of the blood increases (Fig. 6). The more rapidly the urea-N increases, the more rapid is the decrease in blood haemoglobin content ( r ~ 0.89). Subordinate animals can move around normally with values up to 150 mg urea-N/100 ml blood, and they look healthy. If the concentration rises above this level, symptoms of imminent death appear, and the animals die.