FOK is an inbred rat strain with a genotypic adaptation to hot environments. The present study investigated the mechanism of the high heat tolerance of the FOK rat. Male FOK and WKAH rats were used. They were loosely restrained and placed individually in a direct calorimeter with an ambient temperature ...

We investigated the behavioral thermoregulation of heat-acclimated rats by measuring their selected ambient temperatures (Ts). Rats kept in a light:dark cycle of 12:12 h were subjected to one of four different heat exposure regimes for 10 consecutive days; a constant ambient temperature (Ta) of 32 degrees C (CH), a Ta ...

Opposite effects of gentle handling on body temperature and body weight in rats. PHhe aim of this study was to measure the body weight set point when rats are being handled gently and thus experience emotional rise in body temperature. Wistar male rats were used in this experiment, and each ...

Ingestion of MDMA ("ecstasy") by humans can cause acute toxicity manifested by hyperthermia and death. Demethylenation of MDMA is catalyzed by cytochrome P-450 2D6 (CYP2D6) and cytochrome P-450 2D1 (CYP2D1) in humans and rats, respectively, and is polymorphically expressed. It has been proposed that CYP2D6 deficiency may account for the ...

Aging is associated with a blunted or absent fever response to naturally occurring infections or to the peripheral administration of bacterial products and proinflammatory cytokines. We have recently shown that old Long-Evans rats are not defective in their capacity to develop a fever in response to brain administration of interleukin-1beta ...

Near the term of pregnancy, rats have an attenuated core temperature response on exposure to a novel environment (e.g., a simulated open field) compared with that observed early in pregnancy or in nonpregnant rats. The present experiments were carried out on 26 nonpregnant and 26 pregnant rats to test the ...

The lignin component found in both water insoluble (WI) and water and alkali insoluble (WIA) fractions derived from SO(2)-impregnated steam-exploded eucalyptus chips (SEE) was isolated and characterized. Dioxane lignins with a sugar content lower than 2% (w/w) were obtained after each material was treated with commercial cellulases. The C9 formulas ...

PURPOSE: Laser tissue welding has potential advantages over conventional suture closure of surgical wounds. It is a noncontact technique that introduces no foreign body and limits the possibility of infections and complications. The closure could be immediately watertight and the procedure may be less traumatic, faster and easier. In spite ...

The physiological signals are usually extremely complicated and difficult to analyze. Recently, investigators have tried the fractal dimension that can characterize roughness and self-similarity of them. It turns out that it is also suitable for obtaining the modalities of lower urinary tract during normal micturition. In this investigation, the external ...

Respiratory airflow outside the external nares of the rat was mapped by monitoring temperature fluctuations with a thermistor and simultaneous piezoelectric monitoring of respiration-associated chestwall movement. The results demonstrated that both exhalation and inhalation airflow were directed laterally. Relatively little air exchange occurred anterior to the nares. These results suggest ...

Deep body temperature and locomotor activity of rats fed a reduced food amount (n = 9) and of starved rats (n = 9), were measured by implanted transmitters. Both groups were then refed ad libitum. The reduction in body temperature was significant for both groups, but larger in the starved ...

Previous studies have shown that heat acclimation raises the temperature threshold for heat-induced splanchnic vasoconstriction in the rat (W. Haddad and M. Horowitz. Thermal Balance in Health and Disease, Advances in Pharmacological Sciences. Basel: Birkhauser, 1994, p. 203-208; M. Shochina, W. Haddad, U. Meiri, and M. Horo-witz. J. Therm. Biol. ...

BACKGROUND: It is generally accepted that 0 to 4 degreesC is a suitable temperature for organ preservation. The reason for this is based on the premise that at temperatures below 0 degreesC, intracellular ice is likely to form, with subsequent damage to cellular structures. However, it cannot be assumed that ...

Rats have an attenuated febrile response to intravenous endogenous pyrogen [e.g., interleukin-1beta (IL-1beta)] near the term of pregnancy. The present experiments were carried out on 25 nonpregnant and 32 pregnant rats to test the hypothesis that arginine vasopressin functioning as an endogenous antipyretic substance in the central nervous system mediates ...

Although inhalation of nitrous oxide (N2O) causes hypothermia in rats, there is a paucity of information as to whether tolerance develops to this effect. The purpose of this study was to determine whether tolerance to N2O hypothermia develops within a single administration as well as over repeated administrations. Temperature was ...

Aging is associated with a blunted or absent fever response to naturally occurring infections or to the peripheral administration of bacterial products and proinflammatory cytokines, including interleukin-1beta (IL-1beta). Whether old rats also exhibit an attenuated fever response when challenged with direct brain administration of IL-1beta is unknown. Here we investigated ...

The induction of psychological stress in rats is accompanied by an elevation of core temperature. Our experiments were carried out to determine whether the latency, duration, magnitude, or effector mechanisms of the core temperature response to psychological stress would be altered when rats were allowed to use behavioral as well ...

A simple test of critical thermal maximum (CTM) to assess a break-down of heat-escape behavior in rats is described. Experiments were performed on 18 unrestrained adult Wistar rats of both sexes. Hypothalamic and intraperitoneal (i.p.) temperatures as well as motor activity were simultaneously and continuously recorded in the rats exposed ...

This study was designed to assess if opioids or adenosine are involved in the hypometabolism induced by hypoxia in the rat. Accordingly, antagonists such as naloxone (NLX) for opioids or theophylline (THEO) for adenosine were injected into conscious adult rats acutely exposed to either ambient hypoxia (AHx, FIO2: 12%) at ...

The operant system described here contains a box that can be convectively heated or cooled. A rat moves freely in the box. Its location is monitored photoelectrically while its deep body temperature is monitored by a telemetry system. In heat-escape experiments, hot air (40 degrees C) flows through the box. ...

The FOK is an inbred rat strain with a genotypic adaptation to hot environments. The present study compared the thermoeffector thresholds and preferred ambient temperatures (Tpref) of the FOK rat with those of other rat strains. Male FOK, WKAH, and Donryu rats were used. First, they were loosely restrained and ...

The recently described burrow-dwelling Proechimys yonenagae from the Brazilian semiarid caatinga was compared to P. iheringi from the Brazilian rain forest of Mata Atlântica in terms of interactions between body temperature (Tb), ventilation (VE) and oxygen consumption (V(O2)) during hypercapnia (5 or 10% CO2). Wistar rats were also used as ...

The effect on mitochondrial respiration of feeding hydrogenated coconut oil, corn oil, or menhaden oil (MO) to diabetes-prone BHE/cdb rats and normal Sprague Dawley (SD) rats was studied. Both fat source and strain affected the temperature dependence of succinate-supported respiration. The transition temperature was greater in BHE/cdb rats than in ...

The present investigation explored the possible venom neutralizing effect of a pure compound (2-hydroxy-4-methoxy benzoic acid) isolated and purified from the methanolic root extract of Hemidesmus indicus R.Rr. 2-OH-4-MeO benzoic acid possessed potent anti-inflammatory, antipyretic and antioxidant properties. The compound effectively neutralized inflammation induced by Vipera russelli venom in male ...

The amygdaloid body is a telencephalic structure belonging to the limbic system. The amygdaloid body consists of the two main nuclear groups: corticomedial and basolateral. The former-phylogenetically older group is composed of the central, medial, and cortical nuclei, while the latter, phylogenetically younger one, of the lateral, basolateral and basomedial ...

To assess the range of functional responses of the ventilatory apparatus of developing rats and the degree to which ventilatory function is developed in advance of other functional characteristics, rat pups at five ages (between 4 and 20 days old) were exposed to temperatures of 28, 32 and 36 degrees ...

The results of the present study, summarized in Table 2, demonstrate that different species and strains of rodents (rats and mice) and birds (chickens) exhibit rather specific fever response. Systemic administration of LPS caused monophasic elevation in Tb of chickens, biphasic changes in Tb of rats (initial drop followed by ...

The FOK rat was established as an inbred strain with genotypic adaptation to a hot environment. To investigate the mechanism of the heat resistance of FOK rats, heat production by isolated brown adipocytes in FOK and WKAH rats was measured at 37.0 and 39.9 degrees C. Basal heat production by ...

To determine the relationship between cardiac hypothermia tolerance and the sources of activator calcium, we selectively modified either the sarcolemmal calcium permeability by nifedipine or the sarcoplasmic reticulum function by caffeine in papillary muscles from both the rat, as a cold sensitive model, and the ground squirrel, Citellus dauricus, a ...

Moderate changes in body temperature can influence the outcome of cerebral ischemic insults and the effect of drugs. Body temperature was measured continuously for 24 hours in rats subjected to permanent occlusion of the middle cerebral artery (MCA) by either coagulation or thread insertion, and the results correlated with the ...

In order to evaluate the impact of a complete depletion of glucocorticoids on rats' body weight set-point, rats were adrenalectomized, and their set-points were estimated before, and after surgery. Body weight set-points were obtained from a quantitative behavioral method based on the rats' food-hoarding response to weight deficit. In addition, ...

Anesthetized rats exposed to a high ambient temperature develop heatstroke with brain ischemia. Since nitric oxide (NO) plays an important role during normothermic ischemia, its cortical and cerebellar production were continuously assessed in pentobarbital anesthetized rats exposed to heat by using differential pulsed voltammetry. After 60 min at thermoneutrality, the ...

The effect of varying brain temperature on neutrophil accumulation in brain and the expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1) on cerebrovascular endothelium after controlled cortical impact (CCI) was studied in rats. Sprague Dawley rats were anesthetized and subjected to CCI to the left parietal cortex. Ten minutes after ...

The repeatedly observed attenuation of fever in vagotomized rats has been accepted as evidence of an essential role of vagal afferents in the transduction of pyrogenic signals from the periphery to the brain. If, however, the general condition of a vagotomized animal is poor (the usual case) and accompanied by ...

The question addressed was whether orbital bleeding in rats, while under diethylether anaesthesia, affects their locomotor activity body core temperature, heart rate rhythm and eating pattern. Roman High Avoidance (RHA) and Roman Low Avoidance (RLA) rats were used to enhance generalization of the results. Orbital bleeding when the rats were ...

1. We have studied the components of the metabolic acidosis that accompanies urethane anaesthesia in rats, both with and without the hypothermia that results from this anaesthesia. 2. Acid-base disturbances were analysed with an approach based on Stewart's analysis of acid-base chemistry. 3. The pH fall in the blood of ...

Preweaning albino rats were exposed from days 1 to 18 of life to successive 6-h shifts in light and temperature Zeitgebers, (1-18 rats), whereas controls (C) were raised under constant 12:12 L:D and temperature cycles. Cyclic Peak Interval performance at adulthood (100 days) showed that 1-18 rats were more accurate ...

The cardiac capillarity in adult rats reared at 5 degrees C for 68 generations was studied with a double staining method of alkaline phosphatase and dipeptidylpeptidase IV. Capillary density, proportions of arteriolar, intermediate and venular capillary portions and capillary domain area were measured in the left ventricular wall. Compared with ...

We studied the effect of an abdominal prick with a needle on LPS-induced fever in freely-moving rats. LPS was injected intraperitoneally by the following 3 methods: 1) through a hypodermic needle pricked into the abdominal cavity, 2) through a catheter chronically indwelt in the abdominal cavity, and 3) through a ...

Eight- and 11- to 12-day-old rat pups were tested in isolation and in the presence of an anesthetized adult under cold conditions. Pups of both ages reduced rates of ultrasonic vocalization (USV) when an adult was placed into the test cage, independent of whether the adult was their dam or ...

Repeated exposure to heat stress results in physiological adaptations which increase tolerance to heat stress. Core temperature (Tc) and heart rate (HR), two indices of successful heat acclimation, are both increased by the handling and restraint usually required to measure these variables in the rat. This study compares measurement of ...

Caloric overingestion generates a sympathetic nervous system (SNS)-mediated increase in brown adipose tissue (BAT) thermogenesis; its effect on the hypothalamo-pituitary-adrenal (HPA) axis is unknown. To determine whether metabolic activation affects the HPA axis, male rats were provided palatable sucrose ad libitum. After 5 or 10 days of sucrose ingestion, BAT ...

Rats subjected to total sleep deprivation (TSD) by the disk-over-water method were provided with a continuously available operant by which they could increase ambient temperature (T(amb)). TSD rats progressively increased operant responses for heat to 700% of baseline levels. During the last quarter of sleep deprivation, they maintained mean T(amb) ...

Liver hemorrhage, the major cause of death in hepatic trauma, is notoriously difficult to control. We report on the use of high-intensity focused ultrasound (HIFU) to arrest the bleeding from incisions made in rabbit livers. A HIFU transducer, with a spherically curved aperture of 6.34 cm2 area, a focal length ...

The effects of acute lowering of body temperature on afferent sensory transmission to the primary somatosensory cortex were determined quantitatively in anaesthetized rats and hamsters. Rats showed no change in afferent sensory transmission until 27 degrees C, but dramatic suppression between 26 degrees C and 22 degrees C, reaching 100% ...

Guanylyl cyclase C (GC-C), an intestinal receptor guanylyl cyclase, binds diarrhea-producing bacterial ligands such as the Escherichia coli heat stable enterotoxin. We examined the regulatory influence of feeding and fasting on the expression, structure, and biochemical properties of GC-C. When solubilized at 4 degrees C under nonreducing conditions, GC-C from ...

We established an avidin-biotin method for the sensitive determination of rat IgE and found that a non-specific signal was generated depending on the reaction temperature. When the sera of rats immunized or not with ovalbumin (OVA) were fractionated in a hydroxyapatite column and OVA-specific IgE was determined by the avidin-biotin ...

Humans with Parkinson's disease (PD) often have problems in righting themselves, in that they have difficulty in recruiting their axial musculature to rotate the body to prone. Since this "axial apraxia' is not ameliorated by L-DOPA therapy, it has been concluded that dopamine (DA) does not play a role in ...

Recent reports have indicated that rats subjected to total sleep deprivation (TSD) by the disk-over-water method and sacrificed when death appeared imminent showed aerobic bacteria in their blood. Yoked control rats did not. Extrapolating from these results, it has been suggested that the late body temperature declines and eventual deaths ...

The postulated thermoregulatory function of grooming in the "blind" mole rat (Spalax ehrenbergi), a solitary, highly aggressive subterranean rodent, was tested by subjecting individuals to extreme hot and cold environments and measuring their grooming frequency and thermoregulatory capacity. It was found that exposure to heat stress during both the winter ...