Heat-acclimated rats show lighter IBAT deposit with different gross composition and lower GDP-binding than controls at thermoneutrality. A thermal disactivation of the tissue is then inferred. Cafeteria regime increased IBAT mass and GDP-binding when offered to rats at a thermoneutral ambient temperature. These results indicate that BAT thermogenesis at thermoneutrality ...

Male Wistar rats, initially maintained at an ambient temperature (Ta) of 23.8 degrees C, were subjected to one of seven different heat acclimation schedules under a 12:12-h light-dark cycle (lights on at 0600 h). Two groups of rats were exposed to Ta of 32.4 degrees C all day for 5 ...

Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emits far-infrared rays (4-16 microns) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and ...

Incubation of cercariae of Schistosoma mansoni in a 1:1 mixture of Eagle's Minimal Essential Medium and rat serum at 42 degrees C for only 5 minutes, plus subsequent vortexing, resulted in at least 98% conversion of cercariae to schistosomules. Subsequent centrifugation before or after settling for 30 minutes in an ...

The effects of fasting on the febrile responses to intravenous injection of bacterial lipopolysaccharide (LPS; endotoxin) of Escherichia coli were investigated in rats. Ad libitum-fed rats (C) produced a biphasic fever with an increase in the temperature difference between brown adipose tissue and colon and shivering activity (SA). Measurement by ...

Both thyrotropin-releasing hormone (TRH) levels in the hypothalamus and thermoregulatory responses were assessed in rats after they had been equilibrated to each of three ambient temperatures (Ta: 8, 22 and 30 degrees C) tested. Cold exposure, in addition to elevating TRH levels in the hypothalamus, led to increased metabolism and ...

To determine the effect of hypergravity acclimation on thermoregulation, core temperature (Tc), tail temperature (Tt), and O2 consumption (VO2) were measured in control rats (raised at 1 G) and in rats acclimated to 2.1 G. When the animals were exposed to a low ambient temperature of 9 degrees C, concurrently ...

We studied cholinergic regulation of body temperature in hypothyroid rats. Thyroidectomy caused a progressive decrease in core temperature. Intraventricular injection of carbachol in a dose of 10 nmol did not change core temperature of the normal rat, whereas the same dose of carbachol significantly decreased the temperature of thyroidectomized rats. ...

In the present study, a number of physiological and behavioral measures that are related to metabolism were continuously monitored in 19-month-old male Fischer 344 rats that were fed ad libitum or fed a caloric restricted diet. Caloric restricted rats ate fewer meals but consumed more food during each meal and ...

Central microinjection or infusion of an arginine vasopressin (AVP) V1-receptor antagonist within the brain of the conscious, unrestrained, and febrile rat inhibited or abolished the antipyretic effects of peripherally administered indomethacin (Indo). The degree of Indo-induced antipyresis was determined by 2-h thermal indexes (degree C.h) calculated from the time of ...

Previous studies have shown that central injection of bombesin produces hypothermia in food-deprived, but not food satiated rats at normal ambient temperatures. The present study evaluated the effects of bombesin on core body temperature (Tb) and feeding behavior in rats pretreated with insulin. Administration of bombesin (0.25, 0.5, and 1.0 ...

1. The relationship between thermal salivation (TS) and thermoregulation was studied in anesthetized rats. 2. Of the 6 anesthetics used, ketamine-anesthetized rats secreted the largest amount of saliva. Salivation, however, was thermal and not induced by ketamine itself. 3. Ketamine-anesthetized rats readily secreted saliva at core temperatures less than 40 ...

1. The effect of cold environment on the acute toxicity of organophosphates (OP), without and with atropine-oxime treatment, was studied in rats and mice by exposing them to +5 and -5 degrees C temperature. The tested OPs and oximes (given intraperitoneally) were diisopropylfluorophosphate (DFP), isopropyl methylphosphonofluoridate (sarin) and dichlorovinyl phosphate ...

The central action of 1-(2-pyrimidinyl)-piperazine (1-PP), a metabolite of ipsapirone, was studied in mice and rats. 1-PP decreased the locomotor activity and slightly increased the body temperature at an ambient temperature of 21 degrees C, not changing it at an ambient temperature of 28 degrees C. The examined substance antagonized ...

Female Fischer 344 rats, 3, 11, and 24-months old were subjected to 3 hr of restraint-cold stress once each week for 4 weeks. Body (colon) temperature was recorded every 10 min during restraint and during postrestraint recovery until temperature returned to the prerestraint level. Thermoregulatory adaptation during consecutive restraint sessions ...

L-Methionine sulfoximine (MSO) intraperitoneally injected at subconvulsive and convulsive doses induced a rectal hypothermia in the restrained rat maintained at an ambient temperature of 23 degrees C; this hypothermia developed during the preconvulsive period, and it was not suppressed by simultaneous injection of L-methionine which antagonized the behavioral effects of ...

The effects of the serotonergic antagonist cyproheptadine and the agonist 1(m-chlorophenyl) piperazine (mCPP) on core body temperature, locomotor activity and operant responding for a water reward were determined in two lines of Sprague-Dawley rats selectively bred for differences in sensitivity to the anticholinesterase, diisopropyl fluorophosphate (DFP). Both cyproheptadine and mCPP ...

The effects of hyperthermia on blood volume and effective vascular compliance were studied in control and heat acclimated rats (three weeks at 32 degrees C and 50% R.H.). Experiments were performed on conscious rats whose abdominal aorta and both jugular veins were cannulated. Continuous changes in blood volume (BV) were ...

In these experiments representative selective antagonists at D1 (SCH 23390) and D2 (haloperidol) receptors were studied for their effects on basal and apomorphine decreased body temperature in mice and rats. In mice, SCH 23390 (up to 3 mg/kg SC) neither affected basal body temperature nor blocked apomorphine-induced hypothermia (AIH). On ...

Immature rats were tested at 2, 7, 11, and 15 days of age to determine steady-state thermoregulatory responses during light (L) and dark (D) phases of the daily cycle. Pups were housed with dams in a vivarium illuminated from 0700 to 1900 h. During each phase tests began approximately 1 ...

A recent study from this laboratory found that rats placed in a temperature gradient preferred ambient temperatures (Ta) that were significantly below the lower critical Ta of the thermoneutral zone for elevating metabolic rate (MR). To further evaluate the interaction between preferred Ta and MR in the rat, a system ...

The purpose of this study was to examine effects of repeated whole-body hyperthermia on the growth of carcinogen-induced rat mammary carcinomas. Female Sprague-Dawley rats were treated intragastrically with a single dose (100 mg/kg) of the carcinogen 7,12-dimethylbenzanthracene (DMBA) at 2 months of age. Subsequently, when each rat had a minimum ...

Hyperthermia produced a decrease of ornithine decarboxylase activity in different tissues of adult rats. The fall in ornithine decarboxylase was dependent on time of exposure and temperature. The decay of ornithine decarboxylase activity in liver, brain, kidney, heart, spleen and testes was rather similar. The t1/2 for liver ornithine decarboxylase ...

Experimental hypothermia and natural hibernation are two forms of hypometabolism with recognized physiological changes, including depression of endocrine and metabolic functions. To better understand functional changes, helox (i.e., helium and oxygen (80:20) mixtures) and low ambient temperatures have been used to induce hypothermia in hamsters and rats. Both clinical and ...

The stability of cyclocytidine (II) in aqueous solutions decreased with increasing pH and temperature. After intravenous injection to rats the biphasic decline of cyclocytidine in the serum was accompanied by simultaneous formation of arabinosylcytosine. Since under physiological conditions (37 degrees C, pH 7.2) the half-lifetime of cyclocytidine dissolved in water ...

A sensitive and specific radioimmunoassay was used to measure plasma antidiuretic hormone (plasma arginine vasopressin, PAVP) concentrations in a conscious desert-adapted mammal, the banner-tailed kangaroo rat (Dipodomys spectabilis; 131 +/- 2.3 g body mass), during normal hydration and in response to progressive dehydration. Simultaneous measurements of PAVP and plasma osmolality ...

Satietin is a putative satiety agent that is found in a variety of species including man and the rat. In the first experiment male Sprague-Dawley rats were fitted with chronic third ventricle cannulas and placed in activity wheels. After recovery, animals were intracerebroventricularly (ICV) infused with either sterile rat satietin ...

1. In rats acclimated to 23 degrees C (RT rats) or 5 degrees C (CA rats), core temperature (Tc), tail temperature (Tt) and oxygen consumption (VO2) were measured during exposure to a hypergravic field. 2. Rats were exposed for 5.5 h to a 3 g field while ambient temperature (Ta) ...

To investigate the relationship between the thermoregulatory system and the brain-reward system, we examined effects of heat exposure and tail amputation on lever-pressing behavior in intracranial self-stimulating rats. Rats that continuously pressed a lever voluntarily for 1 hour at an ambient temperature (Ta) of 22 degrees C interrupted lever pressing ...

The effect of acetysalicylic acid (aspirin) on thermoregulation in a warm environment was studied in hydrated and dehydrated adult rats to test the hypothesis that dehydration hyperthermia can be modified by an antipyretic drug. Metabolic rate (MR), evaporative water loss (EWL), and deep body temperature (Tb) were measured during 2 ...

Because pentobarbital is often used in investigations related to carbohydrate metabolism, the in vivo effect of this drug on glucose homeostasis was studied. Glucose kinetics, assessed by the constant intravenous infusion of [6-3H]- and [U-14C]glucose, were determined in three groups of catheterized fasted rats: conscious, anesthetized and body temperature maintained, ...

We studied the effect of different levels of hypoxia (10, 12 or 13, 15, and 18% O2) on the sleep-waking pattern (SWP) and the maximum-minimum core temperature of warm-acclimated (WA) and cold-acclimated (CA) rats at their neutral temperature, 29 degrees C. Whereas the SWP of WA rats showed a trend ...

Though the delivery of elemental oxygen to tissues ravaged by anaerobic infection may be useful, little data exists that suggests that such therapy may benefit ischemic tissue. We report the development of a model to test the question that peritoneal lavage with an oxygen containing solution may favorably influence occlusive ...

We studied the respiratory and cardiovascular effects of 1.25 MAC halothane, isoflurane and enflurane in oxygen delivered via the Jackson-Rees breathing system in 10 rats. Mean arterial pressure, heart rate and respiratory rate were depressed significantly (P less than 0.05) in rats (n = 5) whose body temperature was not ...

Studies were conducted to determine if the hypothermic effects of barbiturates were responsible for their ability to suppress luteinizing hormone (LH) secretion in rats following ovariectomy or treatment with gonadal steroids. In both ovariectomized rats and rats treated with estradiol and progesterone, pentobarbital caused a marked hypothermia and blocked LH ...

The increased urine output after injection of the kappa agonist bremazocine was determined in rats of various body weights. Rats of all sizes were sensitive to the diuretic effect of bremazocine. The total diuretic effect was greater in heavier animals. The urine output plateaued between 4-5 ml/100 g body weight ...

Neuronal thermoresponsiveness in the preoptic and anterior hypothalamic (PO/AH) region of a bird and a mammal were compared in vitro by recording the activity of 48 units from ducks and 37 units from rats in tissue slices subjected to temperature changes. Warm-responsive units were found in similar proportions in duck ...

Rats anaesthetized with Brevinarcon were placed in a high-temperature chamber (air temperature 50 degrees C, relative humidity 50%) for induction of hyperthermia (rectal temperature 41.0 +/- +/- 0.5 degrees C). The control group comprised rats anaesthetized in the same way but kept at room temperature. In the serum in both ...

Both virgin and pregnant rats were maintained at two different ambient temperatures (28 degrees C and 10 degrees C) for 19 days. Virgin rats maintained their daily food intake and body weight at both temperatures. At 28 degrees C pregnant rats showed a greater daily food intake and body weight ...

The effects of E. coli endotoxin 0127 B8 on oxygen consumption, temperature, and on the activity of the proton conductance pathway in brown adipose tissue (BAT) were investigated in rats and mice. In rats an increase was observed in rectal and skin temperature, whole body oxygen consumption and GDP binding ...

The extent of systemic arteriovenous shunting (arteriovenous anastomotic blood flow) was assessed in rats with experimental liver cirrhosis and control rats by injecting 15 micron microspheres into the left ventricle and measuring the percentage of injected spheres trapped in the pulmonary circulation. Cirrhotic rats with body temperature maintained at 38 ...

Myosin was isolated from atria and ventricles of adult rats, rabbits and pigs, and characterized by ATPase activities, the effects of temperature on the latter, the influence of alkaline preincubation on enzymatic activity and by electrophoretic fractionation of myosin peptides. It was shown that ventricular myosins are clearly distinguished by ...

This study was designed to elucidate the relationships between behavioral and autonomic thermoregulation in three common strains of the laboratory rat. In one experiment eight adult rats of the Sprague-Dawley (SD), Long-Evans (LE), and Fischer (FCH) strains were repeatedly placed in a longitudinal temperature gradient while their preferred ambient temperature ...

The in situ rat gut technique was used to study the effects of hypothermia on the intestinal absorption of a 1 mg/ml solution of sodium pentobarbital in 0.01 M phosphate buffer (pH 6.0). Male Sprague-Dawley rats weighing between 300 and 370 g were exposed to an atmosphere of helox (helium:oxygen, ...

Pentoxifylline has been shown to increase red blood cell malleability, thus increasing capillary blood flow in a number of disease states. The present study was undertaken to determine whether pentoxifylline might improve tissue oxygenation after anesthesia and during an operation in rats. Rats were anesthetized and divided randomly into pentoxifylline ...

The function of heat defence was compared in rats pretreated as adults (A-rats) and neonates (N-rats) with capsaicin. The thermoregulatory impairment as tested by whole body heating was similar in A-rats and N-rats. The thermosensitivity and chemosensitivity of the preoptic region (RPO) seemed to be normal in N-rats. A deficiency ...

The effects of intraventricular bombesin (BS) at doses of 0.1, 1.0, and 10.0 micrograms on thermoregulatory and cardiovascular functions were studied in conscious rats with a direct calorimeter at ambient temperatures (Ta) of 18, 23, and 28 degrees C. At two lower TaS, the central BS produced a profound decrease ...

Almitrine bismesylate is a peripheral chemoreceptor agonist. When given intravenously to anaesthetized rats it results in a reversible diuresis and natriuresis. The effect is abolished by denervation of the carotid bodies and is still present following vagotomy, when the animal is paralysed and artificially ventilated or following bilateral adrenalectomy. Denervation ...

Rat cadavers oriented perpendicularly to the electric field (parallel to the magnetic field) were exposed to 2.45-GHz microwave radiation. The weight of the cadavers ranged from approximately 5 to 320 g and their lengths ranged from approximately 5 to 22 cm. Average, whole-body specific absorption rates (SAR) were measured using ...

The present work was undertaken to elucidate the underlying causative factors limiting survival in hypothermic rats (non-hibernator) and hamsters (hibernator). A variety of physiological and biochemical parameters were measured for 28 male Wistar rats (205-286 g) and 26 male golden hamsters (85-118 g) before and during induction of hypothermia to ...