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PubMed2003

Reversibility of cold- and light-stress tolerance and accompanying changes of metabolite and antioxidant levels in the two high mountain plant species Soldanella alpina and Ranunculus glacialis.

Two high mountain plants Soldanella alpina (L.) and Ranunculus glacialis (L.) were transferred from their natural environment to two different growth conditions (22 degrees C and 6 degrees C) at low elevation in order to investigate the possibility of de-acclimation to light and cold and the importance of antioxidants and metabolite levels. The results were compared with the lowland crop plant Pisum sativum (L.) as a control. Leaves of R. glacialis grown for 3 weeks at 22 degrees C were more sensitive to light-stress (defined as damage to photosynthesis, reduction of catalase activity (EC 1.11.1.6) and bleaching of chlorophyll) than leaves collected in high mountains or grown at 6 degrees C. Light-stress tolerance of S. alpina leaves was not markedly changed. Therefore, acclimation is reversible in R. glacialis leaves, but constitutive or long-lasting in S. alpina leaves. The different growth conditions induced significant changes in non-photochemical fluorescence quenching (qN) and the contents of antioxidants and xanthophyll cycle pigments. These changes did not correlate with light-stress tolerance, questioning their role for light- and cold-acclimation of both alpine species. However, ascorbate contents remained very high in leaves of S. alpina under all growth conditions (12-19% of total soluble carbon). In cold-acclimated leaves of R. glacialis, malate represented one of the most abundant compounds of total soluble carbon (22%). Malate contents declined significantly in de-acclimated leaves, suggesting a possible involvement of malate, or malate metabolism, in light-stress tolerance. Leaves of the lowland plant P. sativum were more sensitive to light-stress than the alpine species, and contained only low amounts of malate and ascorbate.

Acclimatization↗
PubMed1989

Cold intolerance in patients with angina pectoris: effect of nifedipine and propranolol.

Fifteen patients with chronic stable angina pectoris and a history of reduced exercise tolerance in cold weather (cold intolerance) underwent symptom limited treadmill exercise tests at 20 degrees C and 0 degrees C in a specially constructed cold chamber while taking no antianginal medication. Their mean time to onset of angina (5.8 v 4.2 min), to 1 mm ST depression (5.1 v 3.8 min), and to peak exercise (7.4 v 5.7 min) was significantly shorter on exercise at 0 degrees C than at 20 degrees C. The double product of heart rate and systolic blood pressure at each of these end points was the same in both exercise tests. Eight of these patients were treated with nifedipine 10 mg three times a day for two weeks and then with propranolol 40 mg three times a day for another two weeks. Repeat exercise testing was performed at the end of each two week treatment period. The mean time (SD) to peak exercise at the end of the nifedipine treatment period was 9.1 (2.0) min at 20 degrees C and 8.5 (2.3) min at 0 degrees C. The double product at peak exercise was the same for both exercise tests. At the end of the propranolol treatment period the mean time to peak exercise was significantly less at 0 degrees C (7.8 (2.6) min) than at 20 degrees C (8.9 (2.4) min). The double product at peak exercise was the same for both exercise tests but was significantly less than that on nifedipine. Cold intolerance was shown in patients with a positive history by symptom limited treadmill exercise testing at 0 degrees C. It persisted when they were treated with propranolol, albeit to a lesser extent, but not when they were treated with nifedipine.

Adult↗
PubMed2005

Relationships among Eysenck's extraversion, Rorschach's Erlebnistypus, and tolerance of experimental tonic pain (Cold Water Pressor Test).

In a group of 42 healthy volunteers the correlations between the concept of Extraversion-Introversion as defined by Eysenck and Erlebnistypus as defined by Rorschach were analysed to relate these with the tolerance of an experimentally induced tonic pain. We conducted an experimental procedure comprising a test and retest. At test the subjects were administered the Rorschach, the Eysenck Personality Inventory, the Cold Water Pressor Test, a nongraduated Visual Analogue Scale, and the Italian version of the McGill Pain Questionnaire. At retest the experimental induction of pain was measured again. At test subjects who scored higher on the EPI Extraversion scale tolerated pain longer and did not modify their performance at retest. Also, the concepts of Extroversion defined by the Rorschach test and by the Extraversion scale of the Eysenck Personality Inventory shared some psychophysiological features of higher tolerance to pain. These personality features did not influence how subjects qualitatively describe the immediate painful experience.

Adult↗
PubMed2006

Histamine and its receptors modulate temperature-preference behaviors in Drosophila.

Temperature profoundly influences various life phenomena, and most animals have developed mechanisms to respond properly to environmental temperature fluctuations. To identify genes involved in sensing ambient temperature and in responding to its change, >27,000 independent P-element insertion mutants of Drosophila were screened. As a result, we found that defects in the genes encoding for proteins involved in histamine signaling [histidine decarboxylase (hdc), histamine-gated chloride channel subunit 1 (hisCl1), ora transientless (ort)] cause abnormal temperature preferences. The abnormal preferences shown in these mutants were restored by genetic and pharmacological rescue and could be reproduced in wild type using the histamine receptor inhibitors cimetidine and hydroxyzine. Spatial expression of these genes was observed in various brain regions including pars intercerebralis, fan-shaped body, and circadian clock neurons but not in dTRPA1-expressing neurons, an essential element for thermotaxis. We also found that the histaminergic mutants showed reduced tolerance for high temperature and enhanced tolerance for cold temperature. Together, these results suggest that histamine signaling may have important roles in modulating temperature preference and in controlling tolerance of low and high temperature.

Animals↗
PubMed1989

Colchicine lesions of ventromedial hypothalamus: effects on regulatory thermogenesis in the rat.

Experiments were carried out to test whether the ventromedial hypothalamus (VMH) is the site of a pathway that stimulates thermoregulatory heat production in brown adipose tissue (BAT). Adult Sprague-Dawley rats received bilateral 50 nl microinjections of colchicine solution into the VMH (0.1, 0.32, 1.0 or 3.2 micrograms per side). Beginning a day later, hyperphagia developed consistently with 0.32 microgram colchicine; and with higher doses there appeared the additional effect that for several days rats developed hypothermia when placed temporarily at 6 degrees C. The degree of hypothermia was limited by activation of nonshivering thermogenesis (NST) in BAT, as evidenced by increased shivering after propranolol injection to block NST, and by increased GDP binding measured in IBAT mitochondria after cold exposure. The findings suggest that chemical lesioning to induce the VMH hyperphagia syndrome does not produce an obligatory impairment of thermoregulation against cold unless the dose of neurotoxin and lesion area extends beyond that which underlies the overeating response. Furthermore, when tolerance to cold is thus compromised, the effect is not readily explained in terms of simply disconnecting a proposed stimulatory pathway from the VMH to BAT.

Animals↗
PubMedDate not supplied

Winter swimming: healthy or hazardous?. Evidence and hypotheses.

Swimming in cold water during the winter season is an extreme sport, with fans all over the world. However, its effects on health have been debated. This article examines the hypothesis that the effects of winter swimming may depend on previous exposure to cold stimuli. Immersion in cold water in unaccustomed persons may lead to detrimental consequences, while, in regular winter swimmers, adaptive physiologic mechanisms increase tolerance to cold. Furthermore, these mechanisms may prevent the occurrence of a wide variety of diseases. Prospective studies and epidemiological data are needed to test this hypothesis.

Acclimatization↗
PubMed2002

A cold-regulated nucleic acid-binding protein of winter wheat shares a domain with bacterial cold shock proteins.

The molecular mechanisms of cold acclimation are still largely unknown; however, it has been established that overwintering plants such as winter wheat increases freeze tolerance during cold treatments. In prokaryotes, cold shock proteins are induced by temperature downshifts and have been proposed to function as RNA chaperones. A wheat cDNA encoding a putative nucleic acid-binding protein, WCSP1, was isolated and found to be homologous to the predominant CspA of Escherichia coli. The putative WCSP1 protein contains a three-domain structure consisting of an N-terminal cold shock domain with two internal conserved consensus RNA binding domains and an internal glycine-rich region, which is interspersed with three C-terminal CX(2)CX(4)HX(4)C (CCHC) zinc fingers. Each domain has been described independently within several nucleotide-binding proteins. Northern and Western blot analyses showed that WCSP1 mRNA and protein levels steadily increased during cold acclimation, respectively. WCSP1 induction was cold-specific because neither abscisic acid treatment, drought, salinity, nor heat stress induced WCSP1 expression. Nucleotide binding assays determined that WCSP1 binds ssDNA, dsDNA, and RNA homopolymers. The capacity to bind dsDNA was nearly eliminated in a mutant protein lacking C-terminal zinc fingers. Structural and expression similarities to E. coli CspA suggest that WCSP1 may be involved in gene regulation during cold acclimation.

Amino Acid Sequence↗
PubMed2003

Comparison between NaCl tolerance response and acclimation to cold temperature in Shewanella putrefaciens.

Two strains of the spoiling bacterium S. putrefaciens showed an adaptation capacity to hyperosmotic shock when they were pretreated with a sublethal concentration of NaCl. The maximal tolerance factor for the CIP 69.29 strain was obtained when cells were incubated for 1 h in the presence of 1.5% NaCl, whereas for the J13.1 strain, an incubation of 15 min in the presence of 1% NaCl seemed to be the optimal conditions to harden the cells against a subsequent lethal salt treatment. During NaCl adaptation and growth at low temperatures (2 degrees C), 37 and 32 polypeptides were induced respectively. Interestingly, 11 proteins were common between the two different stress responses. These proteins and the corresponding genes seem to play a key role in the observed cross-protection towards the NaCl challenge induced by growth of the cultures at 2 degrees C. One of the overlapping proteins has been identified to correspond to the alkyl hydroperoxide reductase (AhpC) of S. putrefaciens. Northern blot analysis showed that induction of this enzyme was accompanied by accumulation of the corresponding transcript under both conditions.

Acclimatization↗
PubMed2003

Response to thermal stress and personality.

Tolerance to cold and heat exposure shows large variations for which there is still insufficient explanation. On the other hand the relationship between the responses to mental stress and individual personality is well documented. The aim of this study was then to find if personality traits have some influence on the responses to environmental temperature exposure. A group of 20 young adults were exposed for 90 min to cold (10 degrees C) while skin temperature (Ts), oxygen consumption and discomfort rating were recorded. In a second experiment they were exposed to heat (40 degrees C) for 90 min when the sweat rate and the discomfort rating were recorded. Prior to these tests the Big Five Personality Test was used to measure the personality traits of the subjects. The results show significant negative correlation between neuroticism and the O(2) consumed, the discomfort rating and Ts for the test in the cold, while extraversion was positively related to O(2) consumption but not to Ts and discomfort rating. In response to heat, neuroticism predominance was associated with greater discomfort, reduced tolerance and diminished sweat rate. The discomfort rating, in this case, was negatively related to extraversion. It is proposed that the reduced O(2) consumption in the cold and the lower rate of sweating in the heat observed with neuroticism, are caused by enhanced activity of the sympathetic nervous system. Further investigation is required to assess the validity of this proposal. Overall, the present investigation shows that physical environmental stresses, in common with mental stress, could be in some ways related to personality traits.

Adaptation, Physiological↗
PubMed1990

The effect of training on the norepinephrine response at rest and during exercise in 5 degrees and 20 degrees C environments.

Eleven males were examined at rest and during submaximal exercise in 5 degrees C and 20 degrees C environments to determine if the norepinephrine (NE) and other physiological responses in the cold would be altered by eight weeks of training. Blood samples were obtained at the end of 15 minutes of rest and submaximal exercise, and were assayed for NE. Pretraining resting NE levels in the 5 degrees C condition were significantly higher than those found in the 20 degrees C environment (684 +/- 89 vs 491 +/- 48 pg/ml). A significant training effect reduced resting NE levels in the 5 degrees C (502 +/- 77 pg/ml) but not the 20 degrees C (392 +/- 45 pg/ml) condition. Pre and posttraining exercise NE levels were elevated above resting in both the 5 degrees C (1477 +/- 136 vs 1559 +/- 208) and the 20 degrees C environments (1623 +/- 176 pg/ml vs 1444 +/- 224 pg/ml), but were not significantly different between conditions. Skin temperatures were significantly lower, and resting blood pressure was significantly higher in the 5 degrees C condition. These data suggest that both cold and exercise act as stimulators of NE release, but an additive effect on NE of cold and exercise does not occur. The resting NE levels pre and posttraining in the 5 degrees C condition suggest that a cross tolerance to cold stress was present.

Adaptation, Physiological↗
PubMed1994

Behavioral, physiological, and self-evaluative effects of anxiety on the self-control of pain.

This study examined the impact of trait anxiety on self-control behavior using the cold pressor task. In addition to cold pressor tolerance, effects were measured in terms of physiological arousal and self-evaluations. Forty-six female subjects screened for high and low trait anxiety were given two trials of the cold pressor task, and between trials, they were given either self-control or non-self-control training. As expected, self-control training resulted in increased pain tolerance and decreased physiological arousal. Although anxiety did not influence behavioral tolerance, high trait anxious subjects receiving self-control training made more negative self-evaluations and had higher levels of physiological arousal. These results suggest that anxiety may disrupt the use of self-control strategies in coping with pain.

Adaptation, Psychological↗
PubMed1977

Nutrition and the responses to extreme environments.

The calorie requirements of adequately clothed men living and working in a cold environment are not increased, except for the 2-5 percent increase in matabolic rate due to the "hobbling" effect of the heavy clothing. The energy requirements in the cold, as in a temperate environment, are primarily a function of body weight and level of physical activity. The discrepancies between studies of persons living in a hot environment are explainable and are primarily due to the level of protection from the heat. The increased requirements are probably due to the increased heat load imposed on the body by solar radiation and the extreme heat. The increased requirements, in all likelihood, are a combination of increased action by blood in heat transport, increased ventilation and heart rate, and increased action of the sweat glands plus the increase in metabolic rate due partially to elevation in body temperature. In view of some strong new evidence, the energy requirements are increased for individuals living and working in extremely hot environments. There is no evidence showing that modification of macro nutrient composition of the diet will enhance either heat tolerance or cold adaptation in humans. Recent studies indicate that high carbohydrate diets will improve tolerance during high altitude exposure.

Animals↗
PubMed2000

The cold dependent accumulation of COR TMC-AP3 in cereals with contrasting, frost tolerance is regulated by different mRNA expression and protein turnover.

The accumulation of specific cold-regulated (COR) proteins is a component of the hardening process and different amount of COR proteins has been related to different degrees of cold tolerance. A number of different mechanisms controls the accumulation of the COR proteins in the plant cells. In this work we describe the mechanisms controlling the accumulation of the COR protein TMC-AP3, a putative chloroplastic amino acid selective channel protein [1] in barley, durum, wheat, emmer and bread wheat. Winter barley and, to less extent, winter bread wheat showed a higher cor tmc-ap3 expression at low temperature than the spring one while no significant differences were detected between the emmer and the durum. wheat genotypes. After 2 days of de-hardening the transcript level dropped down in the same way in all tested genotypes, nevertheless the decrease in protein content was genotype dependent. In all frost resistant genotypes the amount of COR TMC-AP3 after 9 days of de-hardening was higher compared with that of susceptible ones. These findings suggest that resistant and susceptible genotypes have different protein degradation rate and/or mRNA translational efficiency. Differences in the protein degradation rate were not dependent from the amino acidic sequence of the protein, being extremely similar in all tested genotypes. A genetic study based on Chinese spring/Cheyenne chromosome substitution lines showed that the turnover of TMC-AP3 is a polygenic trait controlled by a number of loci being the most important located on chromosomes 1B, 2B, 2D and 4D.

Journal Article↗
PubMed1997

[Physiological effects of cabin temperature decrease on human].

To study effects of cabin temperature on human body, changes in rectal temperature, local skin temperature, local skin heat fluxes and skin infrared thermogram were observed in 5 male subjects dressed in different thermal insulation clothings under 20 degrees C, 15 degrees C and 10 degrees C cabin temperatures. The results showed that, average skin temperature and tip temperature obviously dropped, and skin heat fluxes increased with falling of cabin temperature, and changes of local skin infrared thermogram were significant. Subjective feeling were comfortable and cool at cabin temperature of 20 degrees C and 15 degrees C respectively. While subjective feeling was cold and there was a thermal debt of body 144 kJ/m2 at 10 degrees C which indicated that it was slightly cold but tolerable. The results may be valuable in determining the lowest tolerable limit of cabin temperature.

Acclimatization↗
PubMed2005

Cigarette smoking, stress-induced analgesia and pain perception in men and women.

This study examined gender differences in smoking-related analgesia and stress-induced analgesia (SIA), as a function of pain modality. Forty men (20 smokers, 20 nonsmokers) and 37 women (17 smokers) were tested twice for pain sensitivity to tourniquet ischemia, thermal heat, and cold pressor tests; once following mental stress and once following rest control, counterbalancing order. Cardiovascular and neuroendocrine responses to mental stress were also examined. While expected gender differences in pain sensitivity were observed, women smokers had greater threshold and tolerance times to ischemic pain than women nonsmokers (P<0.05) when pain testing followed rest. Male smokers had greater threshold and tolerance to cold pressor pain than male nonsmokers (P<0.05) after both rest and stress. Only women showed evidence for SIA, since women nonsmokers demonstrated greater ischemic pain threshold and tolerance following mental stress versus rest (P<0.05), and all women reported lower thermal heat pain unpleasantness after stress versus rest (P=0.05). Only nonsmokers showed expected inverse relationships between sympathetic and hypothalamic-pituitary-adrenal (HPA) axis reactivity measures and sensitivity to pain. Smokers showed evidence for blunted HPA-axis function at rest and stress. These results indicate that analgesia related to both being a smoker and stress is influenced by gender and pain modality. The reduced pain perception in smokers and absence of relationships between endogenous pain regulatory mechanisms and pain sensitivity may reflect a maladaptive response to chronic smoking.

Adrenocorticotropic Hormone↗
PubMed1994

Corticotropin-releasing hormone mediates the response to cold stress in the neonatal rat without compensatory enhancement of the peptide's gene expression.

A variety of stressors activate the hypothalamic-pituitary-adrenal axis, with secretion and compensatory enhanced synthesis of hypothalamic corticotropin-releasing hormone (CRH). Whether CRH is a major effector in the stress response of the neonatal rat and whether the peptide's gene expression is subsequently up-regulated are not fully understood. We studied the effect of cold-separation stress on plasma corticosterone (CORT) levels and CRH messenger RNA (CRH-mRNA) abundance in the paraventricular nucleus. Rats (4-16 days old) were subjected to maximal tolerated cold-separation. CORT and CRH-mRNA abundance were measured before and at several time points after stress. Cold-separation stress resulted in a significant plasma CORT increase in all age groups studied. This was abolished by the administration of an antiserum to CRH on both postnatal days 6 and 9. CRH-mRNA increased in rats aged 9 days or older, but not in 6-day-old rats, by 4 h after stress. These results suggest the presence of robust CRH-mediated adrenal responses to cold-separation stress in neonatal rats. Before postnatal day 9, however, the compensatory increase in CRH-mRNA abundance is minimal.

Adaptation, Physiological↗