Effects of chronic depletion of high-energy phosphate compounds by feeding beta-guanidinopropionic acid (beta-GPA) with or without hindlimb suspension (HS) on body temperature were studied in rats. Lower rectal and skin temperatures were observed in rats after 10 d of HS. Suspension-related enlargement of the interscapular brown adipose tissue (BAT), associated ...

Body temperature, blood pressure (BP) and heart rate (HR) of rats before and after acclimation to heat were studied in chronically cannulated sedentary conscious rats in different hot environmental conditions [hot/dry: 40 degrees C, 20% relative humidity (RH) and hot/wet: 35 degrees C, 70% RH]. During exposure to heat stress, ...

Reports of the effect of desynchronized sleep (DS) deprivation on body temperature (Tb) of rats in the literature are contradictory. Since conspicuous body weight loss is common in such deprivation, the effect of food plus DS deprivation on Tb of adult male Wistar rats was studied. DS deprivation carried out ...

Old and young male rats (22 and 7 months respectively) were exposed to ambient temperatures of 4, 22, 27 and 35 degrees C. The rats' rectal temperatures (RTs) were measured periodically, after exposure to the varying temperatures at different hours during the day. The mean circadian value of RTs in ...

A nonbarbiturate anesthetic consisting of ketamine HCl (Ketaset) and xlyazine (Rompun) was administered to assess the effects of anesthesia on hypothermia-induced retrograde amnesia in Long Evans hooded and Sprague-Dawley albino rats. Results from Experiment 1a indicate that this anesthetic does not attenuate retrograde amnesia, and the findings from Experiment 1b ...

The effect of temperature changes in the medium on the evoked potentials of pyramidal neurons in response to the electrical stimulation of Schaffer collaterals was investigated in both young (one to two months) and aged (24-28 months) rat hippocampal slices. Temperature increase was shown to reduce, and subsequent temperature decrease ...

Hyper-release of calcitonin gene-related peptide (CGRP) plays a direct and pivotal role in the induction of menopausal hot flushes (HFs), in which a drastic increase in skin temperature occurs. However, it is not possible to investigate whether CGRP induces skin temperature increase and whether skin temperature response to CGRP changes ...

Male Sprague-Dawley rats were used to study the possible role of hyperthermia in the thirst associated with thermal dehydration. Rats were exposed to 40 degrees C for 4 h and then allowed access to water at different times after they were transferred to 25 degrees C. Delaying the time prior ...

The effect of corticotropin-releasing factor (CRF) on ultrasonic vocalizations (USVs) and other behaviors of isolated rat pups was examined at 5/6-, 9/10-, and 13/14-days. The hypothesis tested was that central CRF affects USV rate biphasically: as endogenous CRF increases from low basal levels it initiates USV production, but at higher ...

Tetanus-induced long-term potentiation (LTP) of population action potentials at 22 degrees C was investigated in area CA1 of hippocampal slices prepared from hibernating (HH) and warm-acclimated Turkish hamsters (WH) and rats. LTP elicited at this temperature was significantly stronger in HH slices compared to WH and rat slices. Hibernation-related improvement ...

Chronic total sleep deprivation (TSD) in the rat produces an initial elevation and then declining body temperatures, increasing metabolic rate and eventual death. Because TSD rats will engage in warming behavior, one hypothesis is that the metabolic increase is an unsuccessful attempt at warming to combat a lethal hypothermia. However, ...

Ninety minutes after i.p. injection of 3 mumol of cadmium chloride/100 g body weight into immature, 15 day-old rats, the endothelial intercellular junctions of the caput epididymis capillaries showed none of the lesions such as loss of junctional associated ectoplasmic microfilaments, separation of interdigitated leaflets, disassembling of interendothelial tight junctions, ...

Previous models of rat tail heat transfer have assumed that the tail is uniformly perfused along its length and have introduced questionable assumptions about the heat transfer role of the major axial arteries and the venous blood shunting between the superficial and deep veins. The recent experiments of Lemons and ...

Body core temperature of rats acclimated to heat given daily at a fixed time falls during the previous heat exposure time. In the present study, thermoregulatory responses of heat-acclimated rats were examined during the specific period. Heat-acclimated rats were subjected to an ambient temperature of 32 degrees C for approximately ...

Conscious virgin, pregnant, or lactating rats were given intravenous Escherichia coli endotoxin while their temperatures were monitored telemetrically. Virgin females responded to 10-50 micrograms/kg endotoxin with a slight hypothermia, followed by a fever of nearly 2 degrees C magnitude. In pregnant rats given 25 micrograms/kg of the endotoxin, fevers were ...

To determine how rat mothers protect their pups against pain, we applied focal heat (34-51 degrees C) to the ear or shoulder of 10-day-old rats that were isolated, in contact among themselves or with their mother, suckling nonnutritively, or in the hyperextension position normally caused by milk letdown. Relative to ...

We have observed a novel time and dose dependent stimulatory effect of CRP on the hydrolysis of dipalmitoyl phosphatidylcholine (DPPC) into phosphorylcholine (P-choline) and diacylglycerol (DAG). This effect was shared by rat, rabbit, human and asialo-rat CRP but not by other serum proteins, i.e., albumin, ovalbumin and alpha 1-acid glycoprotein. ...

The proton NMR spin lattice relaxation times of bound water (T1b) were studied on frozen rat liver samples during the precancerous step of cancer induction by diethylnitrosamine. Two components of the T1b were found, which show a different temperature dependence of their relative magnetization. Four different steps were identified during ...

In the present study, we evaluated a large population of aged Long-Evans female rats for the occurrence of spontaneous tail skin temperature (TST) surges. Young (5-7 months) normally cycling (NC) rats and aged (19-29 months), repeated pseudopregnant (PP) and constant estrous (CE) rats were placed in an environmentally controlled room ...

Dehydroevodiamine (DeHE) and evodiamine (EVO), alkaloids isolated from a Chinese medicinal herb, Wu-chu-yu, exhibit calcium antagonistic activity. Intraperitoneal injections of DeHE (5-20 mg/kg) and EVO (2.5-10 mg/kg) caused a dose-related hypothermia in afebrile rats at an ambient temperature (Ta) of 20 degrees C. Because the heat production of alkaloid-injected rats ...

Infrared images of the skull surface were obtained in urethane-anesthetized rats and gerbils before, during and after mechanical stimulation of the face and mystacial vibrissae on one side. Areas of increased temperature on the skull, localized mainly over the face area of the primary somatosensory cortex contralateral to the side ...

The Differential Buoyancy method uses Archimedes' principle to non-invasively determine body fat percentage by measuring the subject's weight in breathable high and low densities atmospheres. We currently use both air and helium/oxygen mixtures in our experiments[1]. When the method was tested on rats, an anomaly was observed. As helium/oxygen mixture ...

The Research Animal Holding Facility (RAHF) and the Animal Enclosure Module (AEM) have housed rats during Space Shuttle flights since the 1980s, but the operational constraints of the hardware have limited the scientific return from these Shuttle flights. The RAHF provides environmental control and monitoring for 24 rats with in-flight ...

Serum albumine from rats at different ages (1, 3, 9, 18 months) undergoes a thermal reversible denaturation in the range of 40-53 degrees C. Thermal transitions of unbuffered solution of native protein show a significant change of pH as they became heat denaturated. The protein molecule has been analysed in ...

Rats were subjected to an ambient temperature (Ta) of 33 degrees C for ca. 5 h during the last half of the dark phase for 5, 14 or 28 consecutive days (heat-exposed rats, HE), while control rats were kept at a constant Ta of 24 degrees C. After the heat ...

BACKGROUND: Since the spatial mobility of subterranean mole-rats is restricted and their skull strongly modified, morpho-functional regression of their vestibular organ may be expected. On the other hand, vestibular sense may be indispensable for orientation in a world deprived of most external sensory cues. Since vestibular sensitivity is determined by ...

The chemokines, macrophage inflammatory protein-1 (MIP-1) and its subunit MIP-1 beta, induce an intense fever in the rat when they are injected directly into the anterior hypothalamic, pre-optic area (AH/POA), a region containing thermosensitive neurons. The purpose of this study was to compare the central action on body temperature (Tb) ...

The effect of horizontal rotation of male rats (70 rpm) on core temperature and spontaneous motor activity levels was examined. In Experiment 1, subjects were chemically labyrinthectomized (VNX) by intratympanic (IT) injections of sodium arsanilate and control rats (VNS) received IT injections of saline. Half of the rats in each ...

Warming one side of a rat's preoptic area and anterior hypothalamus (POAH) suppresses shivering on both sides of the body, and the present study evaluated the extent to which signals mediating this suppression cross the midline within and below the POAH. Hind paw shivering during unilateral POAH thermal stimulation was ...

Warming one side of a rat's preoptic area and anterior hypothalamus (POAH) causes skin vasodilation on both sides of the body, and the present study evaluated the extent to which signals mediating this vasodilation cross the midline within and below the POAH. Hind paw vasomotion during unilateral POAH thermal or ...

The hypercholinergic Flinders Sensitive Line (FSL) rat was significantly more sensitive than the Flinders Resistant Line (FRL) rat to the biotelemetrically recorded hypothermic effects of oxotremorine, a direct-acting muscarinic agonist, and diisopropyl fluorophosphate (DFP), an anticholinesterase agent. The effects of these agents on heart rate and motor activity, also recorded ...

Elevated temperature, normally a characteristic of inflammation, is a potential indicator of periodontal disease. The present investigation examined the relationship of subgingival temperature and various indicators of gingivitis in rats with spontaneous gingivitis (SUS rat) and in control rats (RES rat). In 24 SUS rats with gingivitis, the subgingival temperature ...

Eight rat cadavers, at controlled ambient temperature, were each equipped with electrodes for passing current of constant intensity through the cadaver and for measurement of the potential difference between two points on the anterior abdominal skin. All electrodes were left in situ for the duration of the study, and abdominal ...

The effect of body temperature on cerebral infarcts and thrombolytic therapy was investigated in 91 rats embolized in the right carotid territory. Hypothermia of 32 degrees C for 2 h with preembolic onset (n = 15) or hyperthermia of 39 degrees C for 2 h with postembolic onset (n = ...

Previous research has shown that time before drowning in rats decreases gradually as stress is increased by varying water temperature in the swimming situation. In the present research, the activity of swimming rats appeared to be a U function of varying water temperature, lending support to the notion that activity ...

Central administration of exogenous cyclo(His-Pro) (CHP) is known to produce hypothermia in rodents. In the present study, we examined the role of endogenous CHP in cold-induced hypothermia in the desert rat, Mastomys natalensis. The results of these studies show that a rise in hypothalamic CHP content accompanied a decrease in ...

1. In order to characterize the thermoregulatory actions of brain neuropeptide Y (NPY), the effects of intra-third ventricular (I3V) injection of NPY on temperatures of colon (Tco), brown adipose tissue (TBAT) and tail skin (Ts) were observed at ambient temperatures (Ta) of 19 and 8 degrees C. 2. The injection ...

Perfluorochemical (PFC) emulsions are particulate in nature and, as such, can cause delayed febrile reactions when injected intravenously. This study investigated the influence of emulsion particle size on intravascular retention and on body temperature changes in unrestrained conscious rats. Concentrated (60% to 90% w/v) emulsions based on perflubron (perfluorooctyl bromide ...

It has long been known that the antigenicity of tissues is depressed when they are kept at a very low temperature. In this study, Lewis rats and Brown Norway (B.N.) rats were used because these species are significantly dissimilar at the major histocompatibility complex (MHC) Femoral arteries were harvested from ...

Survival in a confined atmosphere where O2 is limited may be extended by hypothermia. Rats were placed in a thermoregulated sealed chamber which contained a limited amount of air. Rats were studied at low ambient temperatures, in which their terminal rectal temperatures (TB) were 33.2-8.3 degrees C. Rats which had ...

The purpose of this study was to demonstrate resistance adaptation based on genotypic adaptation and to develop an inbred rat strain with genotypic resistance adaptation to a hot environment. Survival time (ST) at an ambient temperature (Ta) of 42.5 degrees C was determined without appreciable thermal damage. Rats with the ...

Erythrocyte osmotic fragility and plasma ionic composition were studied in rats subjected to acute hypothermia. A decrease in osmotic fragility and a significant increase in plasma magnesium and total phosphorus were observed in blood from hypothermic rats in relation to control. A decrease in erythrocyte osmotic fragility from hypothermic animals ...

Total body electrical conductivity (TOBEC) is a simple and non-invasive method for the assessment of body composition in vivo. Information regarding the applicability of TOBEC in the condition of abnormal fluid balance is scarce. In the present paper we give the results of the comparison between TOBEC and total body ...

Subcutaneous and intracerebroventricular (icv) injections of indomethacin were used to test whether prostaglandin synthesis is essential for the exercise-induced increase in a rat's body temperature. At an air temperature of 24 degrees C, male Wistar rats ran on a treadmill at 10-15 m/min 20 min after 300-micrograms icv injection or ...

Changes in body temperature (Tb) and feeding were characterized in unrestrained rats following the micro-injection into the anterior hypothalamic preoptic area (AH/POA) of macrophage inflammatory protein-1 (MIP-1), MIP-1 alpha or MIP-1 beta. After the rats recovered from the stereotaxic implantation of a single guide tube placed in the AH/POA, either ...

In humans, somatic aches and pains are frequently reported during fever. To determine whether exogenous pyrogen administration increases nociceptive responsiveness in rats, the tail flick reflex evoked by noxious heat was compared in animals that received an intraperitoneal injection of exogenous pyrogen (lipopolysaccharide) or vehicle (saline). There were no differences ...

Normothermic (37 degrees C), anesthetized Long Evans rats given unilateral electrical stimulation (0.5 ms monophasic pulses of 100-300 microA at 50 Hz for 30 s) of the posterior hypothalamus (PH) had graded, sustained increases in EMG electrical activity of the gastrocnemius muscle (i.e. shivering). In a current-related manner, gastrocnemius muscle ...

Normal Wistar rats, normal and kininogen-deficient Brown Norway rats were kept at ambiant temperatures of 26 degrees C, 36 degrees C or 40 degrees C for 3 to 5 hours. Their colonic temperatures and body weights were measured. At 26 degrees C, the changes in these parameters were similar in ...

Previous studies of total sleep deprivation (TSD) in the rat have shown an elevation of waking body temperature (Tb) early in the deprivation period. TSD rats defend this rise behaviorally by selecting warm ambient temperatures and autonomically by increasing heat production, thus indicating an elevation of thermoregulatory setpoint. Prostaglandins (PGs) ...

In these experiments we tested the hypothesis that the respiratory events underlying rat pup ultrasonic vocalization (USV) facilitate brown adipose tissue (BAT) thermogenesis, as proposed by Blumberg and Alberts (1990). Laryngeal denervation or tracheostomy were used to reduce or eliminate laryngeal braking and prevent USV in 9- to 10-day-old pups ...