STUDIES OF HOMEOSTASIS IN NORMAL, SYMPATHECTOMIZED AND ERGOTAMINIZED ANIMALS

Abstract

I. In 12 sympathectomized cats exposed to a warm environment (40[degree] C.) a considerably greater rise in body temp. occurred than in normal cats. Ergotaminized cats under the same conditions were even less able to control their body temp. than sympathectomized cats. In a cold environment (9[degree] C.) sympathectomized cats also showed a marked inability to control their body temp. as compared with normal cats. The response of ergotaminized animals to cold was similar to that of the sympathectomized except that the lowering of body temp. was not quite so marked.[long dash]II. Normal trained cats [5] which did not struggle were able to withstand, for at least 1 hr., an O2 tension of 6-8% without collapse. The capacity of [8] trained sympathectomized animals to resist the same test condition was greatly reduced; all of these animals fainted after 15-37 min. exposure to the low O2.[long dash]III. In 11 normal and 6 sympathectomized cats a small standard dose of insulin (0.5 unit per kgm.) caused a fall of blood sugar nearly to the level at which hypoglycemic symptoms appear. At this level the blood sugar usually started to rise in the normal cats with spontaneous recovery, whereas a further rapid drop to the convulsive level took place in the sympathectomized cats. Ergotaminized cats were more sensitive to the standard dose of insulin than the normal but not so sensitive as the sympathectomized cats.[long dash]IV. Sympathectomized cats under dial anesthesia were much more sensitive to hemorrhage than normals. In the latter 30-45% of the blood volume could be removed before the compensatory vasoconstrictor mechanism failed to respond, whereas in the sympathectomized the compensatory reaction was absent after loss of 13-15% of the blood. Ergotaminized cats resembled the sympathectomized but in most cases they showed an even greater lack of vasoconstrictor compensation.