The irritant effect of repeated inhalation exposure to vapors of aqueous formalin (formaldehyde concentration, 15 ppm) in male Charles River CD rats and male C57BL6/F1 mice was determined. The data suggest that rats are relatively insensitive to this irritant while mice are substantially more sensitive, the latter showing a comparable ...

The relative importance of different effector mechanisms of thermoregulation may change depending on their availability. Intact rats make only limited use of a learned response on a cold ambient temperature stimulus, and rely almost entirely on autonomic regulatory functions. After destruction of the anterior hypothalamus, rats exhibit a reduced thermoregulatory ...

Bombesin acts within the anterior hypothalamic preoptic area to interfere with thermoregulation in the rat. The body temperature (Tb) of animals receiving bombesin varies in parallel with ambient temperature (Ta). Bombesin-induced reduction of Tb in animals at low Ta is associated with a marked reduction of oxygen consumption (VO2). Some ...

A group of 25 rats was adapted to cold by housing for five weeks at +3 degrees C. Using thermal stimuli of the scrotal skin, 53 recordings of warm-responsive thalamic and midbrain neurons were analyzed and compared with 84 control recordings from non-adapted rats. The activity of the analyzed neurons ...

The actions of thyrotropin releasing hormone (TRH) were tested on the firing rat of temperature-sensitive and temperature-insensitive neurons in the rat preoptic/anterior area of the hypothalamus (POA). Iontophoretic application of TRH resulted in inhibition of the firing rate of temperature-insensitive, warm-sensitive and cold-sensitive neurons. The inhibitory response of cold sensitive ...

Colonic temperatures were measured in tailed and tailless rats at an ambient temperature (Ta) of 26 degrees C prior to and following administration of isoproterenol, a beta-adrenergic agonist, at doses of 0, 12.5, 25.0, 50.0, and 100.0 micrograms.kg-1. There was no significant difference between the colonic temperatures of tailed and ...

Blind female rats were maintained in running-wheel cages in a 12-h light-dark cycle. Hypothermia was induced by ether anesthesia, wetting of the fur by ethanol, and covering with ice. Rats were put in restraining cages and colonic temperatures were maintained between 20 and 32 degrees C for 3-16 h by ...

To evaluate whether abnormal body composition in uremia is a consequence of undernutrition from poor food intake, body fluid compartments and individual organs were measured in moderately uremic (5/6th nephrectomy) and pair fed control rats and in a second group of moderately uremic and control rats on two levels of ...

The 2-week-old rat has frequently been reported to be hyperactive; however, the causes of this are disputed. In 3 experiments, with split-litter designs, the following possibilities were eliminated as causative factors: (a) body temperature; (b) nest seeking; and (c) maturation of peripheral sensory, motor, and endocrine systems. In contrast, the ...

Inbred Fisher and Buffalo rats were raised in small and in large litters and by such litter manipulation, large- and small-bodied animals were obtained within the same strain. When the rats were exposed to extreme cold and heat, it appeared that large-bodied rats in both strains survived longer in cold ...

Sprague-Dawley rats were raised in an environmentally controlled room at 33 degrees C. Thermoregulatory responses of animals reared in this way were compared with those of control and warm-acclimated rats. Warm-reared animals demonstrated a significantly greater fall in colonic temperature during cold exposure when compared with both warm-acclimated (p less ...

TRH and PS-24 (a TRH peptidase resistant analogue) induce different effects on body temperature and motor activity in rats kept at 4 degrees C. PS-24 induced hypothermia, but TRH did not. PS-24 induced hypermotility, while TRH induced slight hypomotility. The thermal effect of TRH in hypophysectomized rats was similar to ...

An association between hypothermia and gastric ulceration has been reported in rats in cervical cord section and in restraint models. The present study was designed to determine this relationship in cervical and in lumbar cord sectioned Sprague-Dawley rats. Ambient temperatures were varied by placing the sectioned animals in a room-temperature ...

Horseradish peroxidase (HRP) was injected into various nuclei of the amygdala in 50 rats. The retrograde axonal transport of HRP showed various connections arising from the hypothalamic nuclei and the basal forebrain. Neurons of the magnocellular preoptic nucleus send out amygdalopetal axons to all amygdaloid nuclei except the lateral nucleus. ...

The C-terminal octapeptide of cholecystokinin (CCK-8) injected into the lateral ventricle of rats produced a lowering of body temperature. CCK-8 potentiated pentobarbital-induced hypothermia, but not the ethanol one. Thyrotropin releasing hormone (TRH) and prostaglandin E2 (PGE2) antagonized the hypothermic effect of CCK-8. Non-sulfated CCK-8 was ineffective in lowering body temperature, ...

The level of exposure of laboratory animals to 60-Hz electric fields is commonly specified in terms of the unperturbed field strength present before the introduction of experimental subjects and their cages. In the research reported in this paper, rats were housed in two parallel rows in 12.4 cm x 25.1 ...

Effects of photoperiod on heat resistance were studied in 88 rats by observing their survival times in a hot environment (42.5 degrees C). Prior to the experiments individual rats were exposed to a given heat (42.5 degrees C) at a definite time of day and a "predicted survival time" in ...

The inactivation of rat adipocyte Mg2+-dependent phosphatidate phosphohydrolase by noradrenaline [Cheng & Saggerson (1978) FEBS Lett. 87, 65--68; Cheng & Saggerson (1978) FEBS Lett. 93, 120--124] persists for at least 40 min in crude defatted homogenates kept at 0 degrees C or 20 degrees C, but is diminished at 37 ...

Vasodilatation in response to heat, the role of tail vasodilatation in thermolysis and the ability of the animals to use free water for evaporative cooling were studied in control and capsaicin-desensitized rats. 1) While vasodilatation in the tail began in the controls as soon as their temperatures reached 38.5-39 degrees ...

At an ambient temperature (Ta) of 8 degrees C, intraventricular administration of isoproterenol inhibited metabolic heat production and led to hypothermia in rats. In contrast, at a Ta of 22 degrees C and of 30 degrees C, isoproterenol decreased cutaneous circulation and led to hyperthermia. The data indicate that isoproterenol ...

Intraperitoneal administration of prostaglandin E1 (PGE1) produced a hypothermia in rats at room temperatue (22 degrees C). The hypothermia in response to PGE1 was due to cutaneous vasodilatation and decreased metabolic heat production. Depletion of brain 5-hydroxytryptamine (with 5,6-dihydroxytryptamine and p-chlorophenylalanine) did not alter the PGE1-induced hypothermia. However, depletion of ...

Galactose-terminating ligands are specifically recognized by mammalian hepatocytes, internalized, and degraded within lysosomes. We have studied the effects of temperature on this process using 125I-asialofetuin and the perfused rat liver. Uptake and catabolism of 125I-asialofetuin continued but were progressively slowed as the temperature decreased from 35 degrees C to 20 ...

By use of miniature rocket engines, the burn hazard posed by exposure to ejection seat rocket plume flames was determined in the anaesthetized rat. A reference chart is provided for predicting equivalent effects in human skin based on extrapolation of earlier direct measurements of heat input for rat and human ...

The effect of estrogen replacement on several parameters of energy balance was investigated in ovariectomized rats tested during the dark phase of their diurnal cycle. Estrogen replacement, either as 17 beta-estradiol or beta-estradiol-3-benzoate via subcutaneous Silastic capsules, was associated with elevated rates of heat production and dry heat loss relative ...

High mortality rate in rats with large medial preoptic lesions discourage their use in studies of brain function. However, virtually all such animals (six out of seven) survived indefinitely if kept at an ambient temperature of 15 degrees C for 2 hours before and 10 to 12 hours after the ...

Exteroceptive determinants of nipple attachment in albino rat pups were studied by altering maternal sensory features. Rats 15, 20, 25, and 30 days of age were permitted to locate and attach to the nipples of their anesthetized mother after she had received one of the following treatments: (a) thermalnipple and ...

The parenteral administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin-injected rats were held in a controlled environment at 22 degree C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, CW) at 1 mW/cm2, significant increases ...

In the 18.5-day flight of the Soviet biosatellite Cosmos-936 (3-22, August 1977) com-parative investigations of the physiological effects of prolonged weightlessness (20 rats) and artificial gravity of 1 g (10 rats) were carried out. Throughout the flight artificial gravity was generated by means of animal rotation in two centrifuges with ...

Horseradish peroxidase (HRP) was injected to various parts of the amygdala in 50 rats. Retrograde axonal transport revealed that tegmental areas containing biogenic amines: dorsal and median raphe nuclei, locus coeruleus and ventral tegmental area, project diffusely to various amygdaloid areas. Moreover, HRP labeled cells were found in the parabrachial ...

The influence of the motivational state on the discharge rate and flash evoked activity of 57 single units of the dorsal lateral geniculate body (LGB) was investigated using extracellular microelectrodes. Flashes were presented either alone (control group) or followed by water reinforcement (trained group). With decreasing thirst motivation the background ...

Cryo-ultramicrotomy was tested as a tool for the assessment of cardiac damage induced by doxorubicine in rats. Slightly fixed specimens were cut at -80 or -90 degrees C (knife temperature -60 or -70 degrees C), and the ultrastructural changes observed were compared with those found in conventional epoxy sections. It ...

According to current anthropological theory, the two factors that primarily determine thermoregulation in human populations are body size and body proportions, and they have found their formulation in the ecological 'rules' of Bergmann and Allen. In order to test the validity of these idea, Buffalo and Fisher rats were submitted ...

In rats kept under starvation for 25 h after bilateral nephrectomy VO2 is reduced to about 50% of the normal value. The body temperature is conspicuously low (33--34 degrees C), the blood pH about 7.1. Raising the body temperature to normal values by keeping the rats in a thermostat does ...

1 Unilateral intrahypothalamic injection of either dopamine (10 mug) or amphetamine (10 mug) caused a fall in core temperature in the rat. Pimozide (0.5 mg/kg, i.p.) significantly reduced the hypothermic response, whereas pretreatment with phentolamine (1 mg/kg, i.p.) or methysergide (5 mg/kg, i.p.) was ineffective.2 Systemic pretreatment with cocaine (20 ...

Salivary thermolytic mechanisms (weight of salivary glands, effect of desalivation on water intake and body temperature, grooming activity) as well as escape behaviour and reaction to heat pain were studied in capsaicin-desensitized and control rats exposed to various warm ambient temperatures. Body temperature of the desensitized rats increased more than ...

Changes in body water compartments during acute dehydration before and after acclimation to heat and the role of plasma proteins in body fluid dynamics were studied in the rat. Compartment volumes, plasma and interstitial protein concentrations, and colloid osmotic pressures (COP) were measured in anesthetized (with thiopental sodium) and, if ...

Rats with dietary potassium (K) depletion have an altered breathing pattern compared to age matched control rats. The K depleted rats also have a decreased body weight gain, basal metabolic rate and body temperature. In this study, age matched controls are underfed (UFC) to match for body weight gain and ...

In rats, treated with DL-amphetamine + monoamine oxidase inhibitor, and held at an ambient temperature of 28.5 degrees C, hyperthermia was completely eliminated by treatment with pimozide + p-chlorophenyl-alanine. The same drugs markedly reduced the hypothermic effects in rats treated similarly at 4 degrees C. Results implied that serotoninergic and ...

An animal model used yeast-fevered rats to measure the relative antipyretic effects of different commercially available acetaminophen-containing suppositories. A laboratory-prepared acetaminophen-containing suppository and placebo suppositories also were investigated. Release from the suppositories was measured in vitro. All acetaminophen products containing 600 mg of drug elicited significant decreases in the rectal ...

We have determined the age dependence of the characteristics of the cytoplasmic phase separation of lenses from normal and galactosemic young rats. In the normal lens, the temperature at which the phase separation occurs decreases monotonically with age. In the lenses of rats fed with a high galactose diet, the ...

Rats when forced to swim in a restricted space not only became immobile but showed marked hypothermia. The hypothermia was greater than that observed after reserpine or Ro 4-1284 and was not antagonized by imipramine at doses which significantly reduced immobility. Hypothermia induced by forced swimming can therefore be dissociated ...

The action of Merthiolate on the pathogenic yeasts Blastomyces, dermatitidis, Histoplasma capsulatum, and Sporothrix schenckii was compared to the effect of treatment with formaldehyde. Concentrations of 1:10,000 and 1:5,000 Merthiolate for three exposure times (24, 48, and 72 h) at 4 and 25 degrees C were tested on three media ...

Studies both in vivo and in vitro implicate glucocorticoids in various aspects of thermogenesis and prevention of heat loss. Many or most of these effects are probably permissive. Adrenalectomized, cold-exposed rats require glucocorticoids for catecholamine-mediated mobilization of free fatty acids, for shivering responses, and for vasoconstriction and piloerection. Glucocorticoid pretreatment ...

1 Noradrenaline (20 micrograms) and carbachol (1 microgram) injected into the anterior hypothalamus of rats at an ambient temperature of 23 degrees C evoked significant falls in core temperature and increases in tail temperature. 2 When rats were cold-stressed (4 degrees C for 90 min) or cold-acclimated (4 degrees C ...

Unrestrained rats were exposed to cold for 1 h during and immediately after exposure to hypergravic fields (1.5--4 G) to determine if they recover their ability to thermoregulate on reentry to 1-G conditions. In contrast to the decreased body temperatures observed when cold exposure occurred concurrently with acceleration, hypothalamic, carotid, ...

Rats exposed to inescapable heat stress maintained a controlled hyperthermia while increasing heat loss by cutaneous vasodilatation and by grooming behavior. In nonpregnant rats, the evaporation of saliva groomed onto the body surfaces increased exponentially as a function of ambient temperature above 36 degrees C. This was associated with a ...

The thalamo-amygdaloid connections arising in the posterior thalamus were studied in the brains of rats by the Nauta-Gygax and Fink-Heimer methods. They begin mainly in the neurons of the supero-medial area of the posterior segment of the pulvinar and in the peripeduncular nucleus. The amygdalopetal fibers of this pathway pass ...

Buffalo and Fisher inbred rats and their F1--F4 hybrids were exposed to heat, 96 degrees F and 30% humidity, at 35 days of age. Fisher rats which are of lighter weight survive significantly longer than Buffalo rats which are heavier. Body weight was significantly depressed in all hybrids. Only in ...

In a recent series of experiments we have shown that high rates of self injection of nicotine were acquired when rats are at 80% body weight on an FT-1 min food delivery schedule. This rate was significantly higher than that of rats at reduced or normal body weight without food ...

The effects of the H2-antagonists, metiamide and cimetidine, on the oedema following limb ischaemia or scald have been investigated in two strains of rat. No inhibition of oedema formation was found except when large doses of cimetidine were given before scalding. This effect was attributed to the fall in body ...