Children's physical activity level and sedentary behaviour in Norwegian early childhood education and care: effects of a staff-led cluster-randomised controlled trial.

BACKGROUND: A growing body of evidence suggest that the children's physical activity (PA) level in early childhood education and care (ECEC) settings are insufficient. Since most children attend ECEC settings for many hours on most days of the week, and these institutions reach children across the socioeconomic spectrum, the ECEC settings may serve as an ideal avenue for increasing physical activity level, reduce sedentary time and enhance the overall health of young children. This paper investigates the effectiveness of the "Active Kindergarten - Active Children" study to increase children's PA level and reduce sedentary time within the ECEC setting. METHODS: Accelerometers were used to asses PA and sedentary time. A total of 116 three to four-year olds took part in a randomised controlled trial in 11 ECEC settings. Participants were cluster-randomised, by ECEC setting, to either a 12 week staff-led and expert-supported intervention or a waiting list control group. RESULTS: The intervention group increased time spent in moderate- and vigorous intensity PA by 10 min/day (95% CI = 3, 18; P = 0.01), took 1909 more steps per day (95% CI = 1130, 2688; P < 0.01) and reduced sedentary time with 14 min/day (95% CI = - 27, - 1; P = 0.04) compared to the control group. The intervention group had a 2.4 higher odds (95% CI = 1.05, 5.7; P = 0.04) of meeting the PA recommendations compared to the control group at follow-up. CONCLUSIONS: Our results show that a flexible staff-led and expert-supported multicomponent PA intervention can increase total PA level, moderate- and vigorous intensity PA and reduce time spent sedentary in three to four-year old children during their stay in ECEC settings. TRIAL REGISTRATION: The trial was retrospectively registered on September 19, 2020 and available online at ClinicalTrials.gov: No. NCT04555746 .

Exercise training reveals micro-RNAs associated with improved cardiac function and electrophysiology in rats with heart failure after myocardial infarction.

AIMS: Endurance training improves aerobic fitness and cardiac function in individuals with heart failure. However, the underlying mechanisms are not well characterized. Exercise training could therefore act as a tool to discover novel targets for heart failure treatment. We aimed to associate changes in Ca2+ handling and electrophysiology with micro-RNA (miRNA) profile in exercise trained heart failure rats to establish which miRNAs induce heart failure-like effects in Ca2+ handling and electrophysiology. METHODS AND RESULTS: Post-myocardial infarction (MI) heart failure was induced in Sprague Dawley rats. Rats with MI were randomized to sedentary control (sed), moderate (mod)- or high-intensity (high) endurance training for 8 weeks. Exercise training improved cardiac function, Ca2+ handling and electrophysiology including reduced susceptibility to arrhythmia in an exercise intensity-dependent manner where high intensity gave a larger effect. Fifty-five miRNAs were significantly regulated (up or down) in MI-sed, of which 18 and 3 were changed towards Sham-sed in MI-high and MI-mod, respectively. Thereafter we experimentally altered expression of these "exercise-miRNAs" individually in human induced pluripotent stem cell-derived cardiomyocytes (hIPSC-CM) in the same direction as they were changed in MI. Of the "exercise-miRNAs", miR-214-3p prolonged AP duration, whereas miR-140 and miR-208a shortened AP duration. miR-497-5p prolonged Ca2+ release whereas miR-214-3p and miR-31a-5p prolonged Ca2+ decay. CONCLUSION: Using exercise training as a tool, we discovered that miR-214-3p, miR-497-5p, miR-31a-5p contribute to heart-failure like behaviour in Ca2+ handling and electrophysiology and could be potential treatment targets.

Objectively measured physical activity level and sedentary behavior in Norwegian children during a week in preschool.

Although many studies have reported on physical activity (PA) levels using accelerometers, a thorough description of the PA pattern in preschool children during their stay in the preschool, is lacking in the current literature. Furthermore, there remains a lack of understanding of the PA level and pattern in children in the lower end of the PA continuum. The first aim of this study was therefore to describe the PA pattern during a week-long stay in a preschool in all children born in 2011 (either three or four-year-olds) attending public preschools in a municipality in Norway. The second aim was to describe the PA level and pattern of the children who are the least physically active. This cross-sectional study included baseline data from 95% of children (N = 111) participating in a randomized controlled physical activity intervention (Active Kindergarten - Active Children study). The participants wore an Actigraph accelerometer, in week 39 in 2015, from when they arrived at the preschool on Monday morning and throughout their stay of five consecutive days. The amount of moderate- to vigorous-intensity PA (MVPA) per day ranged from 16 min to 116 min, and sedentary time ranged from 2.7 h to 6.5 h per day in the least and most sedentary child, respectively. The least physically active 25% of children were less active throughout the entire day, and only a few of them managed to achieve the recommended level of MVPA on any weekday. The physical activity levels and patterns among the least active children described in this study may help to inform interventions targeting this group.

Role of KATP Channels in Beneficial Effects of Exercise in Ischemic Heart Failure.

PURPOSE: Exercise training reduces pathological remodeling and improves cardiac function in ischemic heart failure; however, causal mechanisms underlying the cardiac benefits of exercise are poorly understood. Because opening of adenosine triphosphate (ATP)-sensitive K ⁺(KATP) channels protects the heart during myocardial stress, we hypothesized that such a mechanism is responsible for some of the cardiac benefits induced by exercise in postinfarction chronic heart failure (CHF). METHODS: Left ventricular myocytes were isolated from three groups of rats: Sham, CHF Tr (4 wk after myocardial infarction, rats underwent 8 wk of aerobic interval training 5 d·wk⁻¹) and CHF Sed (rats sedentary for 12 wk after infarction). Cardiomyocyte survival after oxidative stress exposure (200 µM H2O2) and calcium handling (cells loaded with Fura-2 AM and electrically paced at 1 Hz) were assessed in the presence of KATP channel inhibitor glibenclamide. Expression of KATP subunits (SUR2A and Kir6.2) was evaluated using immunoblotting. RESULTS: Exercise improved cardiac function in CHF Tr animals. Cardiomyocytes from CHF Sed rats were more susceptible to oxidative stress-induced cell death than CHF Tr and Sham cardiomyocytes, with glibenclamide completely abolishing the protective effect of exercise. Glibenclamide did not affect cardiomyocyte survival in Sham or CHF Sed rats. In addition, exercise increased the systolic Ca²âº transient amplitude and improved diastolic Ca²âº removal in CHF Tr cardiomyocytes (compared with CHF Sed); both were significantly attenuated by glibenclamide. Exercise resulted in increased expression of KATP channel subunits in CHF Tr hearts, with more pronounced and significant effect on SUR2A. CONCLUSIONS: Our data suggest that KATP channel upregulation induced by chronic exercise likely mediates some of exercise-induced beneficial effects on cardiac function in postischemic heart failure.

Central gustatory neurons integrate taste quality information from four appendages in the moth Heliothis virescens.

Discrimination between edible and noxious food, crucial for animal survival, is based on separate gustatory receptors for phagostimulants and deterrents. In the moth Heliothis virescens, gustatory receptor neurons (GRNs) tuned to phagostimulants like sucrose and deterrents like quinine, respectively, have indicated a labeled line mechanism for mediating appetitive and aversive information to the CNS. In the present study, we have investigated the central gustatory neurons (CGNs) in this moth as an approach to understand how gustatory information is coded in the CNS. Intracellular recordings from CGNs in the suboesophageal ganglion (SOG) combined with fluorescent staining revealed a large diversity of CGN types responding to sucrose, quinine, water, and mechanosensory stimuli applied to the antennae, the proboscis, and the right tarsus. The CGNs responded with varying tuning breadth to tastants applied to more than one appendage. This integration of information across stimuli and appendages, contradict a simple labeled line mechanism in the CNS for coding identity and location of taste stimuli. Instead the distinct pattern of activity found in an ensemble of CGNs, suggests a population coding mechanism. Staining revealed that the majority of the CGNs were confined locally within the SOG/tritocerebrum, whereas others projected to the deutocerebrum, protocerebrum, frontal ganglion, and thoracic ganglia. Some CGNs were reconstructed and registered into the H. virescens standard brain atlas, showing dendritic overlap with the previously described GRN projections. In general, the physiology and morphology of the CGNs suggested multifunctional properties, where a single CGN might belong to several networks executing different functions.

Electrophysiological characterization of responses from gustatory receptor neurons of sensilla chaetica in the moth Heliothis virescens.

Discrimination of edible and noxious food is crucial for survival in all organisms. We have studied the physiology of the gustatory receptor neurons (GRNs) in contact chemosensilla (insect gustatory organs) located on the antennae of the moth Heliothis virescens, emphasizing putative phagostimulants and deterrents. Sucrose and the 2 bitter substances quinine and sinigrin elicited responses in a larger proportion of GRNs than inositol, KCl, NaCl, and ethanol, and the firing thresholds were lowest for sucrose and quinine. Variations in GRN composition in individual sensilla occurred without any specific patterns to indicate specific sensillum types. Separate neurons showed excitatory responses to sucrose and the 2 bitter substances quinine and sinigrin, implying that the moth might be able to discriminate bitter substances in addition to separating phagostimulants and deterrents. Besides being detected by separate receptors on the moth antennae, the bitter tastants were shown to have an inhibitory effect on phagostimulatory GRNs. Sucrose was highly appetitive in behavioral studies of proboscis extension, whereas quinine had a nonappetitive effect in the moths.

Effects of two bitter substances on olfactory conditioning in the moth Heliothis virescens.

In nature, moths encounter nutritious and toxic substances in plants, and thus have to discriminate between a diversity of tastants. Whereas olfactory learning allowing memory of nutritious plants is well demonstrated, little is known about learning and memory of toxic items in adult lepidopterans. Moths may use bitter substances to detect and possibly learn to avoid noxious plants. We have studied the physiological and behavioural effects of two bitter substances, quinine and sinigrin, on the moth Heliothis virescens. Electrophysiological recordings showed responses to both compounds in gustatory receptor neurons on the antennae. The response patterns suggested a peripheral discrimination between quinine and sinigrin. We evaluated their putative aversive effect in an appetitive conditioning context where the moths learned to associate an odour with sucrose. We first aimed at enhancing olfactory conditioning of the proboscis extension response by testing the effect of the sucrose concentration on acquisition, retention and extinction. 2 mol l(-1) and 3 mol l(-1) sucrose concentration gave similar acquisition, retention and extinction performances. Experiments involving pre-exposure or facilitated extinction with an odour paired with quinine, sinigrin or no tastant showed a latent inhibitory effect, as well as an aversive effect of quinine and, to a lesser extent, of sinigrin. The results suggested that the two tastants may act as negative reinforcers in H. virescens.

Two closely located areas in the suboesophageal ganglion and the tritocerebrum receive projections of gustatory receptor neurons located on the antennae and the proboscis in the moth Heliothis virescens.

Sucrose stimulation of gustatory receptor neurons on the antennae, the tarsi, and the mouthparts elicits the proboscis extension reflex in many insect species, including lepidopterans. The sensory pathways involved in this reflex have only partly been investigated, and in hymenopterans only. The present paper concerns the pathways of the gustatory receptor neurons on the antennae and on the proboscis involved in the proboscis extension reflex in the moth Heliothis virescens (Lepidoptera; Noctuidae). Fluorescent dyes were applied to the contact chemosensilla, sensilla chaetica on the antennae, and sensilla styloconica on the proboscis, permitting tracing of the axons of the gustatory receptor neurons in the central nervous system. The stained axons showed projections from the two appendages in two closely located but distinct areas in the suboesophageal ganglion (SOG)/tritocerebrum. The projections of the antennal gustatory receptor neurons were located posterior-laterally to those from the proboscis. Electrophysiological recordings from the receptor neurons in s. chaetica during mechanical and chemical stimulation were performed, showing responses of one mechanosensory and of several gustatory receptor neurons. Separate neurons showed excitatory responses to sucrose and sinigrin. The effect of these two tastants on the proboscis extension reflex was tested by repeated stimulations with solutions of the two compounds. Whereas sucrose elicited extension in 100% of the individuals in all repetitions, sinigrin elicited extension in fewer individuals, a number that decreased with repeated stimulation.