Thermoregulation in patients suffering from multiple sclerosis (MS) is impaired and may result in either increases or decreases in body temperature. We have found that rat experimental autoimmune encephalitis (EAE), being a model of MS, is associated with body temperature disturbances as well. The purpose of the current study was to examine whether the altered body temperature in EAE-induced rats is due to either a deficit in thermoregulation or a controlled change in its set point. Subcutaneous injection of encephalitogenic emulsion into both pads of hind feet of the Lewis rats provoked EAE symptoms. Body temperature (Tb) of 6 rats was measured using biotelemetry system, and ambient temperature (Ta) preferred by 6 rats of another group was analyzed using thermal gradient system. Symptoms of EAE started 11 days postinjection and progressed quickly, culminating in a complete paralysis in rats placed in the gradient, which was associated with behavioural fever (accordingly, selected Ta raised to as much as 32.8 +/- 0.5 degrees C vs 27.2 +/- 0.6 degrees C in control rats). On the other hand, EAE rats, placed at a constant Ta of 24 degrees C, were able to generate fever (Tb of 37.8 +/- 0.1 degrees C) at the start of the illness and then paralysis compromised fever (most likely due to an impairment of thermogenesis), which, surprisingly, resulted in recovery. We conclude that EAE onset in rats is associated with fever and its behavioural supporting leads to aggravation of the autoimmune neumtoxicity.

A cohort of 183 worker honey bees was used to estimate the effect of the own vs. a foreign colony odor on their olfactory and thermal preferences and metabolic rate. Bees showed a marked preference toward their colony odor and a distinct aversion to the foreign colony odor. Both the preference and aversion were limited to night hours. In contrast, the metabolic rate of bees was affected by the odors during the day only, and then the own colony odor reduced the rate and the foreign colony odor raised it. The changes were accompanied by a decrease and an increase of selected ambient temperature, respectively. Altogether, the foreign colony odor promotes aggressive behavior, which is associated with a huge increase in body temperature, while the own colony odor exerts the opposite, calming effect.

We examined effects of the queen's presence on diurnal rhythms of temperature preference (TP) and locomotor activity (LA) in worker honeybees' groups. TP and LA of six queenless and six queenright (with the queen) groups of bees, consisting of 7-8 worker bees, were recorded in a thermal gradient system for four days, under light to darkness (LD) 12:12 photoperiod. The same experiments were conducted on five virgin queens (of the same age as those in the queenright groups), which were placed individually in the gradient chambers. The single virgin queens showed signs of distress and no rhythms of TP and LA. In contrast, there were diurnal rhythms of TP and LA in both group variants with daytime activity and nighttime rest. However, the queen's presence exerted a strong calming effect, reducing LA of bees both at day- and nighttime. The nighttime minimum LA of queenright groups was five times lower than that in queenless groups. Moreover, there was a reversal of the diurnal pattern of TP in queenright groups. The results are discussed in terms of the bee colony organization as a superorganism.

Honeybee foragers were tested on their preference for the own colony odor either separately, in an olfactometer, or in combination with their temperature preference, in thermal gradient chambers, where their motor activity was also recorded. The bees in the gradient chambers were either deprived of their colony odor for 9 days or exposed to the odor during the experimental days 4–9. The source of odor was wax from the own colony. Bees were attracted by the odor, and this attraction culminated at night. Thermal preference and motor activity fluctuated in a circadian rhythm both in absence and in combination with the own colony odor but there was an upward drift of both variables in bees deprived of the odor. The data are discussed on the background of detrimental effects of isolation from the own colony odor possibly indicating an age related phenomenon.

Brown garden snails (Helix pomatia L.), spend cold winter seasons as well as dry and hot summer seasons in torpor, which is characterized by a strong reduction of metabolic rate (Guppy &Withers, 1999). At the end of winter torpor the snails enhance the capacity of their antioxidant defence system to prevent oxidative stress, which accompanies return from hypometabolism to activity (Nowakowska et al., 2009a). The augmented antioxidant defence, including synthesis of glutathione and glutathione-related enzymes, has also been shown in Cornu aspersum (Ramos-Vasconcelos & Hermes-Lima, 2003; RamosVasconcelos, Cardoso & Hermes-Lima, 2005) during dormancy/ activity cycles. On the other hand, active H. pomatia exhibit a high level of antioxidant defence during summer (Nowakowska et al., 2009b), which can be regarded as a preadaptation to unpredictable, irregular episodes of aestivation. Because the capacity of antioxidant defence in active snails during spring was lower than that recorded at the same time in their counterparts continuing in torpor (Nowakowska et al., 2009a), we wondered how they would respond to aestivation, induced experimentally, in this period. It must be stressed that early spring weather in the north temperate zone of central Poland can occasionally be hot and dry enough to induce aestivation. Therefore, the ability of snails to survive under such stressful conditions should be determined by the adjustment to sudden environmental challenges. We examined the ability of H. pomatia to modulate their antioxidant defence in response to dehydration-induced torpor during early spring and we compared their response with that previously recorded in torpid snails during summer (Nowakowska, Caputa & Rogalska, 2011). The capacity of antioxidant defence was estimated as activities of antioxidant enzymes (catalase, CAT; total glutathione peroxidase, GPX; selenium-dependent glutathione peroxidase, Se-GPX and glutathione transferase, GST), as concentration of reduced glutathione (GSH) and as end products of lipid (thiobarbituric acid reactive substances, TBARS) and protein (carbonyl protein groups, CP) peroxidation during the aestivation/ arousal cycle in the kidney, hepatopancreas and foot of 30 adult specimens of H. pomatia. The snails were collected from their natural habitat in central Poland (538020N, 188350E) as soon as they emerged from winter torpor during spring (24 April) and they were immediately deprived of food and water to induce aestivation (n 1⁄4 18). The aestivating snails were used in one of three experimental treatments: (1) after 3 weeks of aestivation (n 1⁄4 6), (2) just after arousal from aestivation (n 1⁄4 6) and (3) 24 h postarousal (n 1⁄4 6). Snails in groups 2 and 3 were sprayed with water to interrupt aestivation, which happened within a few minutes. The control group (n 1⁄4 6) consisted of active snails, examined just after being collected from the field. In addition, snails in additional control group (n 1⁄4 6) collected in the field together with the experimental snails, were put into a cage, sprayed with water every day and fed ad libitum. These were used to examine the effect of laboratory conditions on the antioxidant defence system. The methods used to examine activities of antioxidant enzymes and concentrations of GSH, TBARS and CP have been described in detail elsewhere (Nowakowska et al., 2009a,b; Nowakowska, Caputa & Rogalska, 2010, 2011; Nowakowska et al., 2014). The results were analysed by two-way ANOVA (experimental conditions x organs as factors), followed by Tukey-Kramer post hoc test. The investigation showed that snails forced to aestivate in early spring did not show signs of preparatory changes for arousal-induced oxidative stress, such as increased level of CAT, which was observed in summer-torpid snails (Nowakowska et al., 2009b; Nowakowska et al., 2010, 2011), but forced aestivation led to a strong decrease in the kidney’s enzyme activity (Fig. 1). In both spring (Fig. 1) and summer aestivation (Nowakowska et al., 2011) the lowest activities of CAT were recorded in the foot and were significantly different (P , 0.001) from those in the hepatopancreas and kidney, but in spring there was no compensatory increase in activity of total GPX in the foot, which has been recorded in summer throughout both torpor and activity cycles and under control conditions (Nowakowska et al., 2011). In the present paper, activity of total GPX was found to be organ-dependent, but it was unaffected by experimental conditions; during the spring, the aestivation/arousal cycle activity of the enzyme remained relatively stable (except for transient changes in postarousal activity of the enzyme in the kidney indicated by the post hoc test, see Fig. 1). Our previous studies showed some discrepancies in activity of total GPX in summeraestivating snails; in one case (Nowakowska et al., 2009b) there was a transient, highly significant increase in the activity in the kidney of snails freshly aroused from aestivation, but in two other cases (Nowakowska et al., 2010, 2011) aestivation/arousal cycles did not influence activity of the enzyme in the kidney or that in two other organs. In the present study, activity of Se-GPX was influenced by experimental conditions and organ type, and the highest activity was recorded in the foot (Fig. 1). Moreover, in all experimental groups, activities of Se-GPX in

After hypoxic-ischemic insult iron deposited in the brain catalyzes formation of reactive oxygen species. Newborn rats, showing reduced physiological body temperature and their hyperthermic counterparts injected with deferoxamine (DF), a chelator of iron, are protected both against iron-mediated neurotoxicity and against depletion of low-molecular antioxidants after perinatal asphyxia. Therefore, we decided to study the effects of DF on activity of antioxidant enzymes (superoxide dismutase-SOD, glutathione peroxidase-GPx and catalase-CAT) in the brain of rats exposed neonatally to a critical anoxia at body temperatures elevated to 39°C. Perinatal anoxia under hyperthermic conditions intensified oxidative stress and depleted the pool of antioxidant enzymes. Both the depletion of antioxidants and lipid peroxidation were prevented by post-anoxic DF injection. The present paper evidenced that deferoxamine may act by recovering of SOD, GPx and CAT activity to reduce anoxia-induced oxidative stress.

It is well known that decrease in body temperature provides protection to newborns subjected to anoxia/ischemia. We hypothesized that the normal body temperature of 33°C in neonatal rats (4°C below normal body temperature in adults) is in fact a preadaptation to protect CNS from anoxia and further reductions as well as elevations in temperature may be counterproductive. Our experiments aimed to examine the effect of changes in body temperature on oxidative stress development in newborn rats exposed to anoxia. Two-day-old Wistar rats were divided into 4 temperature groups: i. hypothermic at body temperature of 31°C, ii. maintaining physiological neonatal body temperature of 33°C, iii. forced to maintain hyperthermic temperature of 37°C, and i.v. forced to maintain hyperthermic temperature of 39°C. The temperature was controlled starting 15 minutes before and afterword during 10 minutes of anoxia as well as for 2 hours post-anoxia. Cerebral concentrations of lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CD) and the activities of antioxidant enzymes had been determined post mortem: immediately after anoxia was finished and 3, 7, and 14 days later. There were no post-anoxic changes in the concentration of MDA, CD and in antioxidant enzymes activity in newborn rats kept at their physiological body temperature of 33°C. In contrast, perinatal anoxia at body temperature elevated to 37°C or 39°C as well as under hypothermic conditions (31°C) intensified post-anoxic oxidative stress and depleted the antioxidant pool. Overall, these findings suggest that elevated body temperature (hyperthermia or fever), as well as exceeding cooling beyond the physiological level of body temperature of newborn rats, may extend perinatal anoxia-induced brain lesions. Our findings provide new insights into the role of body temperature in anoxic insult in vivo.

Hypoxic-ischaemic brain injury involves increased oxidative stress. In asphyxiated newborns iron deposited in the brain catalyses formation of reactive oxygen species. Glutathione (GSH) and vitamin E are key factors protecting cells against such agents. Our previous investigation has demonstrated that newborn rats, showing physiological low body temperature as well as their hyperthermic counterparts injected with deferoxamine (DF) are protected against iron-mediated, delayed neurotoxicity of perinatal asphyxia. Therefore, we decided to study the effects of body temperature and DF on the antioxidant status of the brain in rats exposed neonatally to critical anoxia. Two-day-old newborn rats were exposed to anoxia in 100% nitrogen atmosphere for 10min. Rectal temperature was kept at 33 degrees C (physiological to rat neonates), or elevated to the level typical of healthy adult rats (37 degrees C), or of febrile adult rats (39 degrees C). Half of the rats exposed to anoxia under extremely hyperthermic conditions (39 degrees C) were injected with DF. Cerebral concentrations of malondialdehyde (MDA, lipid peroxidation marker) and the levels of GSH and vitamin E were determined post-mortem, (1) immediately after anoxia, (2) 3 days, (3) 7 days, and (4) 2 weeks after anoxia. There were no post-anoxic changes in MDA, GSH and vitamin E concentrations in newborn rats kept at body temperature of 33 degrees C. In contrast, perinatal anoxia at elevated body temperatures intensified oxidative stress and depleted the antioxidant pool in a temperature-dependent manner. Both the depletion of antioxidants and lipid peroxidation were prevented by post-anoxic DF injection. The data support the idea that hyperthermia may extend perinatal anoxia-induced brain lesions.

The aim of the present study was: to compare thermoregulatory behaviour of single honeybee workers and groups of 3–15 bees over their annual activity period and to check out whether the annual fluctuations of ambient temperature selection are correlated with phases of the colony development. Thermal behaviour of both single workers and groups of bees was recorded, using a video camera, in a thermal gradient system. Thermal preferences of the insects were tested seasonally in spring (May/June), summer (July/August) and autumn (September–November). Both single bees and small groups of bees changed their thermal behaviour in daily cycle. The season of the year had distinct effect on temperature preferences of both single honeybee workers or small groups of bees. In single honeybee workers the lowest ambient temperatures were preferred in late spring (the swarming phase) while the highest temperatures were selected during the summer (the colony growing phase). There were significant seasonal changes in ambient temperature selected by groups of honeybee workers. Groups of honeybee workers tended to prefer the lowest temperatures in late spring and the highest temperatures were selected during the summer. The day-night differences exhibited by small groups of bees in our experiments are likely to represent behavioural responses of the honeybee colony. In our experiments we proved an influence of the season of the year on the honeybees’ thermal behaviour, which might be connected with seasonal shifts of temperature regulated by the honeybee colony.

1. Bailey S. E. R. 1981. Circannual and circadian rhythms in the snail Helix aspersa Muller and the photoperiodic control of annual activity and reproduction. J. Comp. Physiol. 142A: 89–94. http://dx.doi.org/10.1007/BF00.... CrossRef Google Scholar

This paper studied the association between metals accumulation in selected tissues and the shell and antioxidant defence system in Helix aspersa snails.Accumulation of Zn, Fe, Pb, Cd, and Mg was organ-specific and was the highest in the hepatopancreas. Hepatopancreatic catalase and glutathione peroxidase activities were the highest, whereas the highest glutathione reductase activity was recorded in the foot. Concentration of GSH was inversely proportional to hepatopancreatic accumulation of the metals. The metals accumulation did not affect hepatopancreatic lipids peroxidation, which means that the hepatopancreatic antioxidant defence was quite capable of eliminating the overproduction of reactive oxygen species evoked by metals.

We present a study on the association between accumulation of heavy metals and activities of antioxidant enzymes, concentra-tions of glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) as products of lipid peroxidation in selected tissues of Helix pomatia living in a natural habitat. Hepatopancreatic accumulation of Zn, Cd and Mg was many times higher than that in the kidney and foot, and was connected to an extremely high concentration of TBARS and activity of glutathione transferase. Moreover, the organ concentration of GSH was inversely proportional to TBARS. Activity of glutathione reduct-ase was unaffected by organ type. In contrast to the metals mentioned above, concentrations of Pb, Cu and Ni were extremely high in the kidney and shell and low in the hepatopancreas. The results confirm the crucial role of the hepatopancreas and kid-ney in the detoxification process and point to the shell as a ‘sink’ for some heavy metals.

The aim of this study was to evaluate whether the day–night cycle phase is a critical factor modulating diurnal rhythm of isolated honeybee's thermal preference or other factors are involved. The insects were exposed to standard (LD 12:12) and reversed (DL 12:12) photoperiods as well as to constant light and constant darkness conditions. Thermal preference and motor activity of honeybees were recorded for 3–5 days in a thermal gradient system. Under the standard (control) photoperiod conditions mean values of temperature selected by honeybees changed rhythmically within the period of about 24h. Honeybees, exposed to the modified light–darkness cycle distinctly modified their rhythm of thermal preference. Under the reversed photoperiod conditions period of selected ambient temperature was much longer than before, until a complete reversal of the circadian oscillation was established at the end of the experiment. Experiments performed under constant light and constant darkness yielded undisturbed 24h rhythms of both ambient temperature selection and locomotor activity. Under these conditions only a slight, nonsignificant flattening of the temperature selection curves was noticed. Both lack of substantial changes in the amplitude and occurring phase shifts of the rhythm, recorded in our experiments suggest its endogenous character. Our results prove that diurnal rhythm of ambient temperature selection by bee workers may be entrained by light–dark cycles. This implies a critical role of photoperiod in the modulation of nychthemeral oscillations of thermal preference in honeybees.

During summer, land snails are exposed to estivation/arousal cycles that imposes oxidative stress, but they exhibit different patterns of antioxidant defence. To test the ability of two related species, Helix pomatia and Helix aspersa, to modulate their antioxidant defence mechanism during estivation/arousal cycles, we examined activities of catalase and glutathione-related enzymes and concentrations of glutathione and thiobarbituric acid reactive substances (TBARS; as products of lipid peroxidation). In both species, estivation evoked changes in activity of total and selenium-dependent glutathione peroxidase (GPx), but did not affect activity of catalase, glutathione reductase, and glutathione transferase, and had no effect on concentration of glutathione. Activity of catalase in estivating snails, instead of the expected increase, showed a tendency to diminish. Extremely low activities of catalase in the foot were usually associated with extremely high activities of both forms of GPx. In conclusion, maintenance of relatively high activities of the antioxidant enzymes and accumulation of glutathione, resulting in a low and stable concentration of TBARS, plays an important role in scavenging oxygen free radicals from the organism of both species.

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Neonatal anoxia is an example of early-life threatening experience that might exert long-lasting behavioral disturbance. One of the consequences of neonatal asphyxia is hyperactivity in open-field test. Changes in open-field activity are coupled with changes in the function of the hypothalamic–pituitary–adrenal (HPA) axis. A critical determinant of the severity of hypoxic–ischemic brain injury in newborn rats is body temperature. Hyperthermia under anoxic conditions increases locomotor activity in the open-field test. Therefore, the aim of the present study was to test whether body temperature during neonatal anoxia can affect basal and stress-induced corticosterone secretion in rats. At the age of 2 days Wistar rat pups were exposed to anoxia in 100% nitrogen atmosphere. Rectal temperature was kept at 33 °C (typical for the rat pups), or was elevated to a level typical for febrile adults (39 °C). Control rats were exposed to atmospheric air under the respective thermal conditions. Basal and stress-induced corticosterone levels were assessed using sulphuric acid-induced fluorescence, on postnatal day 14. Body temperature during neonatal asphyxia altered the early developmental profile of plasma corticosterone. Hyperthermia under anoxic conditions decreased the corticosterone response to open-field stress. In conclusion, febrile body temperature changes corticosterone release, which might induce neurobehavioral disturbances. On the other hand, a protection against the HPA dysfunction can be achieved by the reduced physiological neonatal body temperature.