A characteristic symptom of neuropathic pain is mechanical allodynia. In animal models of neuropathic pain, mechanical allodynia is often assessed using von Frey filaments. Although the forces applied with these filaments are highly reproducible, there are various disadvantages of using this method. Testing paradigms and definitions of withdrawal threshold are ...

The purpose of this study was to evaluate the potential of a xyloglucan formulation with in situ gelling properties for the oral sustained delivery of paracetamol. Gelation of dilute aqueous solutions of the polysaccharide xyloglucan occurred in rabbit and rat stomachs as the orally administered chilled solutions attained body temperature. ...

BACKGROUND: Temperature is an important modulator of the evolution of ischemic brain injury--with hypothermia lessening and hyperthermia exacerbating damage. We recently reported that children resuscitated from predominantly asphyxial arrest often develop an initial spontaneous hypothermia followed by delayed hyperthermia. The initial hypothermia observed in these children was frequently treated with ...

The aim of this investigation was to study the effect of temperature on the permeation of imipramine hydrochloride (IMH) across rat skin from two different vehicles. Differential scanning calorimetry (DSC) was used to characterize the phase transitions of rat epidermis and extracted rat SC lipids, and the transition temperatures were ...

BACKGROUND/PURPOSE: Sepsis is an important cause of neonatal mortality. The aim of the study was to investigate the metabolism of endotoxic neonatal rats and the potential beneficial effect of glutamine. METHODS: Suckling rats received intraperitoneal saline (control; C), endotoxin (300 microg/g LPS; E), saline+glutamine (2 mmol/g; CG), endotoxin+glutamine (EG), saline+leucine ...

BACKGROUND/AIMS: Little information is available regarding the effect of cold storage and hyperthermic preconditioning on the contractile responses of hepatic vessels. We then studied, after cold preservation, the in vitro contractile responses of rat portal veins (RPV) isolated from normal rats or from rats previously subjected to hyperthermia. METHODS: Rats ...

To determine the effects of high temperature on the number of alveolar macrophages (AMs) in bronchoalveolar lavage (BAL) fluid in rats, F344 rats were housed in environment chambers at 23 degrees C, 30 degrees C or 35 degrees C for up to 14 days. The number of AMs in the ...

Attenuation coefficient and propagation speed of intercostal tissues were estimated as functions of temperature (22, 30, and 37 degrees C) from fresh chest walls from eight 10- to 11-week-old female Sprague-Dawley (SD) rats, eight 21- to 24-week-old female Long-Evans (LE) rats, and ten 6- to 10-week-old mixed sex Yorkshire (York) ...

We describe the use of a commercially available telemetry and data acquisition system to record heart rate, body temperature and activity of freely behaving rats with transmitters that operate without batteries (transponders). The system uses PDT 4000HR E-Mitters (Mini Mitter, OR, USA) to acquire animal temperature, heart rate and motor ...

Body surface zones or 'thermatomes', whose temperature is regulated by a single spinal segment, were investigated by thermography in the rat hindlimb. First, the spatial relation between the dermatome delineated by dye extravasation and the corresponding thermatome was investigated in rats pretreated with intravenous application of Evans blue. Electrical stimulation ...

Rats have an attenuated febrile response to endogenous pyrogen near the term of pregnancy. Given the fundamental role of E-series prostaglandins (PGEs) in mediating the febrile response to blood-borne endogenous pyrogen, the present experiments were carried out to determine whether PGEs increase in the area surrounding the organum vasculosum laminae ...

There are many important considerations in the interactions among the herbal constituents in a prescription of traditional Chinese medicine (TCM). Ephedra Herb [Chinese characters: see text] (Eph) is described a warm and acrid agent in TCM. The combination of Eph and Gypsum [Chinese characters: see text] (Eph-Gyp) shows specific actions ...

There is a misbelief that the same animal has the same thermoneutral zone (TNZ) in different experimental setups. In reality, TNZ strongly depends on the physical environment and varies widely across setups. Current methods for determining TNZ require elaborate equipment and can be applied only to a limited set of ...

An asphyxial cardiac arrest rat model, originally developed for Sprague-Dawley rats, was transferred to a Wistar rat model. Several strain specific life support adjustments, i.e. ventilator settings, anaesthesia, and drug requirements, were necessary to stabilize the model for Wistar rats. Despite these arrangements numerous resuscitation related variables appeared different. Three ...

INTRODUCTION: Measurement of tail skin temperature (T(sk)) of the rat can provide important information on mechanisms pertaining to physiology, pharmacology, and toxicology. T(sk) is largely under control of peripheral vascular tone, which is also sensitive to most experimental manipulations such as handling and restraint. Hence, it is extremely difficult to ...

The physiological, metabolic and anatomical adaptations of skeletal muscle to chronic cold exposure were investigated in Wistar rats (Rattus norvegicus), a species that defends core temperature, and Syrian hamsters (Mesocricetus auratus), which may adopt a lower set point under unfavourable conditions. Animals were exposed to a simulated onset of winter ...

In a previous study of volume-controlled hemorrhagic shock (HS) in awake rats, without fluid resuscitation, either breathing of 100% oxygen or moderate hypothermia while breathing air, increased survival time. We hypothesized that combining oxygen and hypothermia can maximally extend the "golden hour" of HS from which resuscitation can be successful ...

OBJECTIVE: To determine whether the neurotensin analog NT69L, administered systemically, could induce mild brain hypothermia after asphyxial cardiac arrest (ACA) in rats. METHODS: The study design was experimental, blinded, randomized, and approved by the animal use committee. All rats had continuous monitoring of brain temperature and sustained 8 minutes of ...

This study was conducted to find out whether the medial preoptic area (mPOA) plays a role in the selection of ambient temperature by rats. Adult male Wistar rats were kept in an environmental chamber having three interconnected compartments, maintained at three different temperatures (18 degrees, 24 degrees and 30 degrees ...

BACKGROUND: Although neonatal rats have become widely used as experimental laboratory animals, minimum alveolar concentration (MAC) values of volatile anesthetics in rats during postnatal maturation remain unknown. METHODS: We determined MAC values of volatile anesthetics in spontaneously breathing neonatal (2-, 9-, and 30-day-old) and adult Wistar rats exposed to increasing ...

We examined the storage stability of metallothionein (MT), a cysteine-rich protein that has diagnostic potential as a cancer marker and in the assessment of Zn status and heavy-metal toxicity. MT was rapidly degraded in samples of rat whole liver at -20 degrees C or -70 degrees C. MT in supernatants ...

The quantitative autoradiographic 2-[(14)C]-deoxy-D-glucose methods were used to assess the local cerebral glucose utilization (LCGU) in 46 brain structures in rats suffering from heatstroke. Heatstroke was induced by exposing the animals to an ambient temperature of 42 degrees C. The time at which the local cerebral blood flow (CBF) and ...

To clarify the role of the preoptic area and anterior hypothalamus (PO/AH) on thermoregulatory system and the effects of serotonergic innervation from the median raphe nucleus (MRN) on body temperature (Tb), we perfused tetrodotoxin (TTX) solution into the PO/AH or MRN by using a microdialysis technique at different ambient temperatures ...

Temperature is a powerful regulator of the behavior and physiology of newborn altricial animals. The effects of warmth on newborn rats' oral responsiveness to suckling stimuli and spontaneous motor activity in a thermoneutral environment were investigated. Newborn rat pups' oral grasp responses to an artificial nipple and overall motor activity ...

Body (core) temperature (T(c)) directly affects all biological processes, including sensitivity to toxic chemicals, development, aging, and drug metabolism. To understand how T(c) affects these processes it is necessary to alter T(c) independently of other physiological processes. The purpose of this study was to determine whether selective breeding techniques can ...

Effects of estrogen on thermoregulatory vasomotion and heat-escape behavior were investigated in ovariectomized female rats supplemented with estrogen (replaced estrogen rats) or control saline (low estrogen rats). First, we measured tail temperature of freely moving rats at ambient temperatures (T(a)) between 13 and 31 degrees C. Tail temperature of the ...

When rats, acclimated to an ambient temperature (T(a)) of 29 degrees C, are exposed to 10% O(2) for 63 h, the circadian rhythms of body temperature (T(b)) and level of activity (L(a)) are abolished, T(b) falls to a hypothermic nadir followed by a climb to a hyperthermic peak, L(a) remains ...

Mild hypothermia as an intervention after perinatal asphyxia may prevent neurological damage in the newborn. We used stimulus-induced field potentials to monitor recovery from oxygen and glucose deprivation (OGD) in neocortex slices of 6-8-day-old wistar rats. OGD after a latency of 10.7+/-2.1 min (mean+/-S.E.) resulted in an anoxic depolarisation with ...

Allyl sulfur compounds are the major active constituents found in crushed garlic. Research has revealed that garlic and its lipid- or water-soluble components have many pharmacologic properties; however, studies also demonstrate that heating has a negative influence on these beneficial effects. We recently conducted several studies to investigate the influence ...

Male rats and hamsters were exposed to a progressively lower air temperature and shorter photoperiod to simulate the onset of winter. Normothermic hamsters had a higher haematological oxygen carrying capacity (OCC) and coagulability (shorter prothrombin time and activated partial thromboplastin time) than rats. Cold acclimation significantly increased the OCC of ...

We examined the effects of progesterone on the elevation of tail skin temperature (TST) in ovariectomized rats and compared them with those of estradiol. Progesterone showed only insignificant effects on the TST elevation, whereas estradiol showed complete inhibition. The TST elevation induced by ovariectomy is caused by estradiol deficiency, but ...

To test the hypothesis that the body mass of rats is increased during spaceflight, we developed two models from the literature and obtained mass measurements during spaceflight. From studies of centrifugation (hypergravity), there is a reduction in body mass of rats dependent on the exposure gravity level. From data in ...

Ringtail is a pathologic condition of the tail of rats and other rodents that is traditionally attributed to low environmental humidity, although dietary deficiencies, genetic susceptibility, environmental temperature, and degree of hydration of the animal also have been suggested as possible causes. To the authors' knowledge, a detailed histopathologic study ...

Reticuloendothelial system (RES) particulate uptake (PU) of vascular debris influences survival from extreme hyperthermia. Little is known of the effect of extreme hyperthermia, unrelated to fever, on RES PU shortly after reaching a maximum core temperature (T(c)). Relative to normothermic rats (T(c)=38.0 degrees C), rats at T(c)=42.6 degrees C had ...

Fever, a hallmark of disease, is a highly complex process initiated by the action of a number of endogenous pyrogens on the thermosensitive cells of the brain. We describe the activity of RANTES, a chemotactic cytokine, as intrinsically pyrogenic in the rat, when it is delivered directly to the thermosensitive ...

On six days rats were exposed to each of two contexts. They received an electric shock in one context and nothing in the other. Rats were tested later in each environment without shock. The rats froze and defecated more often in the shock-paired environment; they also exhibited a significantly larger ...

In mammals that use the ventilatory system as the principal means of increasing heat loss, raising body temperature causes the adoption of a specialised breathing pattern known as panting and this is mediated by the thermoregulatory system in the preoptic area of the hypothalamus. In these species an additional respiratory ...

To clarify the mechanism by which changes in chronic pain are induced by cold environments, rats rendered neuropathic by a chronic constriction injury (CCI) to the sciatic nerve were exposed to low ambient temperature (LT; 7 degrees C decrease from 22 degrees C) in a climate-controlled room. LT exposure aggravated ...

In Cnidaria, a separation between soma and germline remains unclear. In this work, we studied the origin of germinal cells and determination of the sexual phenotype in Clytia hemisphaerica and Clytia sp. Colonies of C. Hemisphaerica were cultivated and the medusae liberated by each colony raised until maturity. Two hermaphrodite ...

1. We investigated the mechanism of starvation-induced hypothermia in rats. 2. Threshold core temperatures (Tcor) for tail skin vasodilatation and cold-induced thermogenesis were determined after a 3 day starvation using a chronically implanted intravenous thermode. Food deprivation significantly lowered the threshold Tcor for heat production, but did not affect the ...

The cause of the cycle of urinary alcohol levels (UALs) in rats fed ethanol continually at a fixed rate is unknown. Rats were fed ethanol intragastrically at a constant dose for 2 mo, and daily body temperatures and UALs were recorded. Body temperature cycled inversely to UAL, suggesting that the ...

An inhalation exposure system, consisting of an inhalation chamber and an generating and feeding device for welding fumes and gases with a welding robot, was constructed and examined for its application to experimental toxicology for ventilatory responses of conscious rats to welding fumes and gases. The exposure system allowed an ...

CCl4-induced toxic damage to the liver in rats and rabbits is accompanied by inhibition of detoxifying functions of the liver and a decrease in plasma alpha1-antitrypsin content and core body temperature. Injection of pyrogenal stimulated detoxifying functions of the liver, elevated alpha1-antitrypsin content in the blood, and increased body temperature. ...

Rats subjected to total sleep deprivation (TSD) by the disk-over-water method exhibit an elevated temperature set point, increased energy expenditure (EE), and increased circulating norepinephrine--all of which should militate for an increase in body temperature. Instead, after a small rise early in TSD, intraperitoneal temperature (T(ip)) fell progressively, indicating a ...

Menopausal hot flushes (HFs), which manifest as an increase in skin temperature, most frequently occur after menopause and cease with the passage of time. We designed this study to elucidate the characteristics of the elevation of tail skin temperature (TST) in ovariectomized (OVX) rats, which is relevant to human symptoms ...

In rats, prolonged stable hypothermia ( approximately 24 h at body temperature of 19 degrees C) is characterized by a time-dependent increase in hematocrit, plasma osmolality, and red blood cell fragility and a decrease in plasma volume. These changes impede tissue microcirculation and could limit survival. As a countermeasure, we ...

The hydraulic conductivity in the presence of dimethyl sulfoxide Me(2)SO (L(p)(Me(2)SO)), Me(2)SO (P(Me(2)SO)) permeability and reflection coefficient (sigma) of immature (germinal vesicle; GV) and mature (metaphase II; MII) rat oocytes were determined at various temperatures. A temperature controlled micropipette perfusion technique was used to conduct experiments at five different temperatures ...

OBJECTIVES: To measure articular structures' contribution to the limitation of range of motion after joint immobility. STUDY DESIGN: Experimental, controlled study involving 40 adult rats that had one knee joint immobilized in flexion for durations of 2, 4, 8, 16, and 32 weeks; 20 rats underwent a sham procedure. The ...

The temperature sensitivity of in vitro whole bladder preparations from neonatal and adult rats with or without chronic partial urethral obstruction was investigated. After the bladder was filled to a volume eliciting isovolumetric contractions, temperature was changed between 19 and 38 degrees C. In all preparations, higher temperatures were associated ...

A battery of histological and histochemical techniques was applied on the lead intranuclear bodies that have resuted in the kidneys of adult Wistar male rats receiving lead acetate in their diet to determine their nature. The intranuclear inclusion bodies have stained strongly with xanthene, anthraquinone, and trisulfonated basophilic dyes and ...