Serum glucose, serum free fatty acids and adipose tissue lipids after fatal hypothermia of cold acclimatized, reserpine or propranolol treated guinea-pigs

[Changes in skeletal muscles in death caused by hypothermia]

The review of 32 deaths resulting from hypothermia yielded mostly the common pathological findings as bright red livores, haemolytic frost marks of the skin and Wichnewski erosions of the gastric mucosa. In addition the muscle system of the body core (musc. ileopsoas) showed hemorrhages and histologically necrosis of its fibres in form of segmental and discoid sarcoplasmatic alteration. These changes are a quite specific sign of death due to hypothermia, as far as mechanical injury can be excluded. For best result however a special autopsy technique and an appropriate histological staining are advisable.

Changes in body temperature after administration of adrenergic and serotonergic agents and related drugs including antidepressants: II

This survey continues a second series of compilations of data regarding changes in body temperature induced by drugs and related agents. The information listed includes the species used, the route of administration and dose of drug, the environmental temperature at which experiments were performed, the number of tests, the direction and magnitude of change in body temperature and remarks on the presence of special conditions, such as age or brain lesions. Also indicated is the influence of other drugs, such as antagonists, on the response to the primary agent. Most of the papers were published from 1980 to 1984 but data from many earlier papers are also tabulated.

Lowered cold tolerance in cold-acclimated and non-acclimated guinea pigs treated with diazepam

The effects of the clinically most commonly used minor tranquilizer, diazepam, on the survival time and on the mechanism of death in non-acclimated and cold-acclimated guinea pigs in severe cold exposure (-20 degrees C) were studied. Cold acclimation for 2 months increased the average survival time from 4 h to 10 h. The lowest rectal temperature at death (14.6 degrees C) was seen in the cold-acclimated animals. Diazepam at a dose of 5 or 15 mg/kg i.p. 30 min before the beginning of the exposure reduced dose-dependently the cold endurance of both cold-acclimated and non-acclimated guinea pigs. The serum glucose and free fatty acid concentrations were low in the animals with the long survival time. Histological studies of liver, kidney, and adrenal glands showed no specific changes. Exposure seemed to increase the frequency of contraction bands and to decrease focally the intensity of beta-hydroxybutyrate dehydrogenase reaction in the myocardium, which indicates a mild hypoxic lesion of the muscle cells.

Effects of reserpine and propranolol on urinary excretion of histamine and 5-hydroxytryptamine in severe cold exposure in normal and cold-acclimated Guinea-pigs

The effects of cold-acclimation, reserpine and propranolol were investigated on the survival time, rectal temperature and urinary excretion of histamine and 5-HT in guinea-pigs at -20 degrees C. Both reserpine and propranolol shortened survival time by 3 hours and 1.5 hours respectively, the shortest time being in the cold-acclimated reserpine-treated animals. There was a trend in severe cold exposure to increased excretion of histamine both in the non-acclimated and in cold-acclimated animals. Reserpine did not change the excretion but increased the concentration of histamine from 0.08 to 0.25 microgram/ml. Propranolol proved to be a histamine liberator by increasing the excretion in non-acclimated from 0.10 to 1.40 microgram/h and concentration from 0.10 to 4.52 microgram/ml and in cold-acclimated animals the excretion from 0.20 to 2.85 microgram/h and the concentration from 0.08 to 3.23 microgram/ml. Severe cold increased the excretion of 5-HT in the non-acclimated animals from 0.08 to 0.21 microgram/h and cold acclimation increased this to 0.17 microgram/h. Reserpine diminished the excretion from 0.08 to 0.03 microgram/h in the non-acclimated animals, but propranolol had no effect. The results showed that the excretion of histamine and 5-HT into urine are changed in cold and can be modified with drugs. The application of the findings in proving a cold stress deserves further study.