Divergent selection for basal metabolic rate in mice affects the abundance of UCP1 protein: implications for translational studies.

Low basal metabolic rate (BMR) is a risk factor for obesity, whereas elevation of non-shivering thermogenesis (NST) is a promising means to combat obesity. Because heat generated by NST covers thermogenic needs not fulfilled by BMR, one can expect the presence of a negative relationship between both parameters. Understanding of the mechanisms underlying this relationship is therefore important for interpretation of the results of translational experiments and the development of anti-obesity treatments.

Reproduction results in parallel changes of oxidative stress and immunocompetence in a wild long-living mammal-edible dormouse .

Oxidative stress (OS) and impaired immune function (IF) have been proposed as key physiological costs of reproduction. The relationship between OS and IF remains unresolved, particularly in long-living iteroparous species. We studied physiological markers of maintenance (OS, IF markers) in lactating, post-lactating and non-lactating females of edible dormice-a long-living rodent.

Significance of variation in basal metabolic rate in laboratory mice for translational experiments.

The basal metabolic rate (BMR) accounts for 60-70% of the daily energy expenditure (DEE) in sedentary humans and at least 50% of the DEE in laboratory mice in the thermoneutral zone. Surprisingly, however, the significance of the variation in the BMR is largely overlooked in translational research using such indices as physical activity level (PAL), i.e.

Development and Validation of the Brief Folate-Specific Food Frequency Questionnaire for Young Women's Diet Assessment.

The tools enabling brief assessment of folate intake may be of great value for public health purposes. The aim of the presented study was to design a brief folate-specific food frequency questionnaire for Central and Eastern European population of women, as well as to assess the validity and reproducibility of the designed Folate-Intake Calculation-Food Frequency Questionnaire (Fol-IC-FFQ) on a group of Polish women aged 20-30 years. Participants collected 3-day dietary records and completed the Fol-IC-FFQ twice (FFQ1: directly after the dietary record; and FFQ2: six weeks later).

The nexus of hair corticosterone level, immunocompetence, metabolic rates and overwinter survival in the root vole, Microtus oeconomus.

Although corticosterone (CORT) regulates many physiological mechanisms, the associations between CORT levels, immunocompetence, energy expenditures and overwinter survival have not been examined. Here, we studied individual variation in CORT level extracted from hair, immunocompetence quantified as the neutrophil-to-lymphocyte (N/L) ratio, total white blood cells (WBC) and natural antibody levels (NAbs), along with the resting (RMR) and peak metabolic rates (PMR) and mortality during three consecutive winter seasons in a natural population of the root vole, Microtus oeconomus. In early winter, hair CORT level was strongly positively associated with body mass and inversely related to voles' ability to survive.

Effect of calorie restriction on spontaneous physical activity and body mass in mice divergently selected for basal metabolic rate (BMR).

Spontaneous physical activity (SPA) represents an important component of daily energy expenditures in animals and humans. Intra-specific variation in SPA may be related to the susceptibility to metabolic disease or obesity. In particular, reduced SPA under conditions of limited food availability may conserve energy and prevent loss of body and fat mass ('thrifty genotype hypothesis').

Heat dissipation does not suppress an immune response in laboratory mice divergently selected for basal metabolic rate (BMR).

The capacity for heat dissipation is considered to be one of the most important constraints on rates of energy expenditure in mammals. To date, the significance of this constraint has been tested exclusively under peak metabolic demands, such as during lactation. Here, we used a different set of metabolic stressors, which do not induce maximum energy expenditures and yet are likely to expose the potential constraining effect of heat dissipation.

Immunocompetence and high metabolic rates enhance overwinter survival in the root vole, Microtus oeconomus.

Despite its presumed significance, the association between immune defence, energy expenditures and overwinter survival is rarely studied. We analysed individual variation in immunocompetence quantified as neutrophil-to-lymphocyte ratio (N/L), total white blood cells (WBC) and natural antibody levels, along with resting (RMR) and peak metabolic rates (PMR) and mortality during three consecutive winter seasons in a natural population of the root vole, Microtus oeconomus. In early winter, WBC count was negatively correlated with RMR, whereas N/L ratio was negatively correlated with swim-elicited PMR.

Shaving increases daily energy expenditure in free-living root voles.

Experimental manipulation of energy expenditure has long been recognized as an effective means for identifying causative effects and avoiding confounded interpretations arising from spurious correlations. This approach has been successfully applied mainly to studies on birds, particularly on reproducing adults, whereas manipulations in mammals have proved more problematic. Here, we tested the hypothesis that shaving off 50% of the dorsal pelage should effectively increase energy expenditure in wild root voles (Microtus oeconomus) in their natural environment.

Relationships between dominance, testosterone level and scent marking of males in a free-living root vole (Microtus oeconomus) population.

In many species, dominance increases a male's mating success via intrasexual competition and/or female choice. The level of androgen hormones, mainly testosterone (T), the intensity of scent marking and body mass are traits that are known to be linked to mammalian male social rank. Recently, however, it has been noted that this link between male dominance and the aforementioned traits in natural free-living populations is not universal and does not exist in some species.

High basal metabolic rate does not elevate oxidative stress during reproduction in laboratory mice.

Increased oxidative stress (OS) has been suggested as a physiological cost of reproduction. However, previous studies reported ambiguous results, with some even showing a reduction of oxidative damage during reproduction. We tested whether the link between reproduction and OS is mediated by basal metabolic rate (BMR), which has been hypothesized to affect both the rate of radical oxygen species production and antioxidative capacity.

Properties of BK-type Ca(+) (+)-dependent K(+) channel currents in medial prefrontal cortex pyramidal neurons in rats of different ages.

The medial prefrontal cortex (PFC) is involved in cognitive functions, which undergo profound changes during adolescence. This alteration of the PFC function derives from neuron activity, which, in turn, may depend on age-dependent properties and the expression of neuronal ion channels. BK-type channels are involved in controlling both the Ca(+) (+) ion concentration in the cell interior and cell excitability.

Effect of dopamine receptor stimulation on voltage-dependent fast-inactivating Na(+) currents in medial prefrontal cortex (mPFC) pyramidal neurons in adult rats.

Impaired working memory is a common feature of neuropsychiatric disorders. It is dependent on control of the medial prefrontal cortex (mPFC) neurons by dopamine. The purpose of this study was to test the effects of a D1/5-type dopamine receptor agonist (SKF 38393, 10 microM) on the membrane potential and on voltage-dependent fast-inactivating Na+ currents in mPFC pyramidal neurons obtained from adult (9-week-old) rats.

Determinants of intra-specific variation in basal metabolic rate.

Basal metabolic rate (BMR) provides a widely accepted benchmark of metabolic expenditure for endotherms under laboratory and natural conditions. While most studies examining BMR have concentrated on inter-specific variation, relatively less attention has been paid to the determinants of within-species variation. Even fewer studies have analysed the determinants of within-species BMR variation corrected for the strong influence of body mass by appropriate means (e.

Effect of dietary restriction on metabolic, anatomic and molecular traits in mice depends on the initial level of basal metabolic rate.

Dietary restriction (DR)-related delay of ageing is hypothesized to be mediated by the reduction of the metabolic rate (MR). However, studies on the effect of DR on MR have produced equivocal results. We demonstrated that this lack of congruency can be due to a variation in the initial level of MR within a given pool of experimental subjects.

Effect of dietary restriction on immune response of laboratory mice divergently selected for basal metabolic rate.

To study whether dietary restriction (DR; 70% of ad lib. feeding)-elicited immunosuppression results from the trade-off between the costs of mounting an immune response and the metabolic costs of maintenance, we subjected mice from two divergent lines selected for high basal metabolic rate (H-BMR) and low BMR (L-BMR) to 4 wk of DR and then challenged them with keyhole limpet hemocyanin (KLH) antigen. Those line types differ genetically with respect to BMR and to the mass of metabolically expensive internal organs, which are larger in H-BMR mice.

Phenotypic flexibility of traits related to energy acquisition in mice divergently selected for basal metabolic rate (BMR).

Theoretical considerations suggest that one of the main factors determining phenotypic flexibility of the digestive system is the size (mass) of internal organs. To test this, we used mice from two lines selected for high and low levels of basal metabolic rate (BMR). Mice with higher BMRs also have larger internal organs and higher daily food consumption (C) under non-stressful conditions.

Anatomic and molecular correlates of divergent selection for basal metabolic rate in laboratory mice.

Proximal mechanisms describing the evolution of high levels of basal metabolic rate (BMR) in endotherms are one of the most intriguing problems of evolutionary physiology. Because BMR mostly reflects metabolic activity of internal organs, evolutionary increase in BMR could have been realized by an increase in relative organ size and/or mass-specific cellular metabolic rate. According to the "membrane pacemaker" theory of metabolism, the latter is mediated by an increase in the average number of double bonds (unsaturation index) in cell membrane fatty acids.

Artificial selection on metabolic rates and related traits in rodents.

Artificial selection experiments are potentially powerful, yet under-utilized tool of evolutionary and physiological ecology. Here we analyze and review three important aspects of such experiments. First, we consider the effects of instrumental measurement errors and random fluctuations of body mass on the total phenotypic variation.

Anatomic and energetic correlates of divergent selection for basal metabolic rate in laboratory mice.

The aerobic capacity model postulates that high basal metabolic rates (BMR) associated with endothermy evolved as a correlated response to the selection on maximum, peak metabolic rate Vo2max. Furthermore, the model assumes that BMR and Vo2max are causally linked, and therefore, evolutionary changes in their levels cannot occur independently. To test this, we compared metabolic and anatomical correlates of selection for high and low body mass-corrected BMR in males of laboratory mice of F18 and F19 selected generations.

Costs of immune response in cold-stressed laboratory mice selected for high and low basal metabolism rates.

To study whether mounting an immune response is energetically costly, mice from two lines divergently selected for high (H-BMR) and low (L-BMR) basal metabolic rate (BMR) were immunized with sheep red blood cells. Their energy budgets were then additionally burdened by sudden transfer from an ambient temperature of 23 degrees C to 5 degrees C. We found that the immune response of H-BMR mice was lower than that of L-BMR mice.

Delayed effects of cold stress on immune response in laboratory mice.

This study was undertaken to examine the trade-off between the cost of thermoregulation and immune function in laboratory mice. Mice were maintained either at 23 degrees C or cold exposed at 5 degrees C for 10 days. Then, they were immunized with sheep red blood cells.