Blocking in the Morris swimming pool.

Four experiments demonstrate that spatial blocking is governed by the same principles that govern blocking in Pavlovian conditioning. In the 2nd stage of each experiment, rats escaped from a Morris swimming pool by swimming to a submerged platform with a beacon attached to it. Test trials were then conducted in the absence of the platform and the beacon to assess the extent to which subjects had learned about the position of the platform with reference to the room cues. For the 1st stage of their training, rats either swam to the platform and beacon in the presence of curtains that prevented the room cues from being seen (Experiments 1 & 2), or they swam to the platform and beacon that were moved from trial to trial (Experiments 3 & 4). In each experiment, learning about the room cues in the 2nd stage of the experiment was blocked by the presence of the beacon. This blocking effect was disrupted by changing the appearance of the beacon for the 2nd stage of training or by restricting the amount of exposure to the beacon during the 1st phase of training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition by a capsaicin antagonist (capsazepine) of capsaicin-induced swimming capacity increase in mice

We investigated the endurance swimming capacity of mice injected with CAP antagonist (capsazepine). The increase of endurance swimming capacity by the administration of CAP was significantly suppressed by the injection of capsazepine. At the same time, serum adrenaline secretion, which was induced by CAP, was depressed by capsazepine. These findings suggested that the increase in endurance swimming capacity by CAP was mediated by the CAP receptor.     

Active preexposure enhances attention to the landmarks surrounding a Morris swimming pool.

Rats were required to swim to a hidden platform in order to escape from a Morris pool, after they had been exposed to the landmarks around the pool by swimming to a platform that had a beacon attached to it. The platform occupied a different place for the test trials than for the preexposure trials. Escape from the pool was facilitated if the landmarks remained in the same place throughout preexposure, but if their positions were changed during preexposure, then subsequent escape from the pool was disrupted (Experiment 2). Escape learning was also disrupted if the rats were placed on the platform for their preexposure treatment (Experiment 3). The results indicate that the associability of the cues around a Morris pool may be enhanced when they are in a stable spatial relationship with the platform throughout each preexposure session. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of rats and mice in a swimming pool place task and matching to place task: some surprising differences

An ecological niche that requires competency in water has prepared rats for the swimming pool spatial tasks that they are administered in the laboratory. Their ability to eventually solve spatial tasks in a single trial makes them ideal subjects for evaluating neural contributions to spatial behavior and for addressing many other neuroscience problems. Swimming pool place tasks are also given to mice, but the spatial abilities of the animal has not been evaluated as extensively as have those of rats. In the present paper, place learning in a single place task and a matching to place task is comparatively assessed in groups of rats and mice. The rats were superior to the mice on both problems. Although the mice could learn a single place problem, their acquisition was slower and their asymptotic performance was inferior to that of rats. Mice also did not display one trial learning on the matching to place task as did rats. These species differences in swimming pool place learning are discussed with respect to both methodological considerations and to species differences in preparedness to learn. It is suggested that given the variability of the performance of mice across both strains and laboratories, rat performance could be used to provide a baseline for comparative purposes.     

Influence of carbohydrate supplementation early in exercise on endurance running capacity

The aim of this study is to examine the effect of carbohydrate (CHO) ingestion during the first hour of treadmill running on endurance capacity. Eleven male subjects ran at 70% VO2max to exhaustion on three occasions one week apart. On two occasions two CHO-electrolyte solutions (a 5.5% (E) and a 6.9% (L) were ingested for the first hour of exercise; water was ingested until exhaustion. On the third occasion water (W) was ingested throughout the run. The order testing was randomly assigned. Exhaustion times for the W, E, and L trials were 109.6 +/- 9.6 min, 124.5 +/- 8.4 min, and 121.4 +/- 9.4 min, respectively. There was no difference between the two CHO trials, but time to exhaustion was longer only for the E trial (P < 0.05), compared with the W trial. Nevertheless the average performance times for the combined results of the two CHO trials were longer than the water trial. Carbohydrate ingestion resulted in higher blood glucose concentration (P < 0.01) at 20 min in the E trail only and lower (P < 0.05) serum growth hormone and plasma FFA and glycerol concentrations at 60 min but not at exhaustion in both E and L trials compared with the W trial. Blood lactate, plasma ammonia, electrolytes, catecholamines, and serum insulin and cortisol concentrations were not different in the three trials. In conclusion, CHO ingestion during the first hour of exercise improves endurance capacity go a greater extent compared with water alone.     

Cholinergic receptor blockade in the rat impairs locale but not taxon strategies for place navigation in a swimming pool.

Normal Long-Evans hooded rats and rats drugged with atropine sulfate (10–200 mg/kg, intraperitoneally), a cholinergic muscarinic blocker, were evaluated in the Morris water task for their use of spatial navigation strategies. Atropine-treated Ss were impaired on a place response of swimming to a platform hidden in a pool filled with opaque water. With extended training, they did learn the place response, though not with the precision of controls. Acquisition could not be accounted for by habituation to the drug. In contrast with the acquisition deficit, pretrained Ss were relatively unimpaired by the drug. Atropine-treated Ss were not impaired in acquisition or retention of a cue task (swimming to a visible platform) or a position response task (turning to locate a platform). Atropine-treated Ss were unable to acquire a place learning set or to perform a learning-set response that they had acquired when undrugged. The impairments following atropine were characteristic of a deficit in the use of a locale strategy (rapid use of relational properties of distal cues), whereas their successes were characteristic of the use of taxon strategies (cue or position responses). Results suggest that locale systems of navigation are more importantly dependent on cholinergic brain mechanisms than taxon strategies. The resistance of preacquired place responses to atropine suggests that normally rats acquire place responses by using a locale strategy but effect rehearsed responses by using taxon strategies. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Skeletal muscle fatigue and physical endurance of young and old mice

In order to evaluate the role played by muscular and extramuscular factors in the development of fatigue in old age, the time course of fatigue in isolated skeletal muscles and spontaneous motor activity and endurance of whole animals were monitored using young (3-6 months) and old (34-36 months) CF57BL/6J mice. The isolated extensor digitorum longus (EDL) and soleus muscles from old mice had smaller (P < 0.05) mass and developed lower (P < 0.02) maximal tetanic tension at 100-Hz stimulation than the muscles of young mice. During stimulation at 30 Hz every 2.5 s, a 50% decline in original tetanic tension occurred by 109 s in young EDL and 129 s in old EDL, but by 482 s in young soleus and 1134 s (projected) in old soleus, indicating more (P < 0.05) resistance to fatigue in old than young soleus. However, the old mice showed significantly fewer (P < 0.002) spontaneous ambulatory movements than the young mice. On a treadmill with a belt speed of 10 m/min at an inclination of 0 degrees, the old mice could only run for 22 min compared to 39 min ran by young mice (P < 0.02). They took more rest periods (P< 0.02) than the young mice. In a quantitative swimming monitor, the old mice swam for a shorter (P < 0.05) time than young mice (20.4 min compared to 28.6 min). Integrated swimming activity at 20 min was smaller (P < 0.05) in old mice than in young mice (413 g/s compared to 628 g/s). Hence increased fatigue in old age is not caused by impairment of processes within the muscles, but by impairment of central or extramuscular processes.     

Learning impairments of hippocampal-lesioned mice in a paddling pool.

Control mice rapidly learned to escape from shallow water in a paddling pool, which combined elements of the Morris water maze and the Barnes holeboard maze. The pool's transparent perimeter wall contained 12 exits, only 1 of which led to an escape tunnel. Learning was impaired in mice with cytotoxic lesions of the hippocampus. Probe trials suggested that the controls were using extramaze cues. When the exit was blocked, controls, but not hippocampals, spent more time searching in this previously correct sector. When the spatial location of the exit was changed, hippocampals escaped more quickly, as they showed no preference for the old location. These results may be useful in the assessment of hippocampal dysfunction, particularly in genetically manipulated mice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Health effects of attending a public swimming pool: follow up of a cohort of pupils in Paris

OBJECTIVES: This study aimed to determine the health effects of attending a well-kept school swimming pool maintained according to French public health regulations. METHODS: This prospective month long study was carried out on a randomised sample of pupils aged 5 to 18 years who attended a private French school with two swimming pools. The children surveyed, helped by their parents, had to fill in questionnaires about their bathing habits and symptoms during the survey period. Inspections of the pool complex were made and these included physicochemical and bacteriological analyses of the pools' water. PARTICIPATION: The response rates achieved were 70% at primary and middle school levels but only 25% in the high school pupils. Because of this older teenagers were excluded from the final analysis (of 246 children). RESULTS: Compared with non-bathers, bathers experienced fatigue and eye irritation significantly more often (p < 0.001). The eyes were red (38% of bathers) and/or watery (16%) after swimming but this resolved spontaneously within 24 hours. Bathing behaviour (bath duration, head immersion, wearing swimming goggles) did not affect these incidence rates noticeably. There were no differences between bathers and non-bathers with regard to other symptoms, especially otolaryngological ones. This survey does not allow definite conclusions to be made about verrucas because 22% of non-bathers were exempted from swimming because of verrucas that they might have caught previously in a pool. CONCLUSIONS: Except for verrucas, the methodology was adequate and daily self reporting of symptoms was feasible. This college largely recruits pupils from higher social classes and is not therefore representative of schools in Paris.     

The zinc pool is involved in the immune-reconstituting effect of melatonin in pinealectomized mice

Melatonin (MEL) affects the immune system by direct or indirect mechanisms. An involvement of the zinc pool in the immune-reconstituting effect of MEL in old mice has recently been documented. An altered zinc turnover and impaired immune functions are also evident in pinealectomized (px) mice. The present work investigates further the effect of "physiological" doses of MEL on the zinc pool and on thymic and peripheral immune functions in px mice. Daily injections of MEL (100 micrograms/mouse) for 1 month in px mice restored the crude zinc balance from negative to positive values. Thymic and peripheral immune functions, including plasma levels of interleukin-2, also recovered. The nontoxic effect of MEL on immune functions was observed in sham-operated mice. Because the half-life of MEL is very short (12 min), interruption of MEL treatment in px mice resulted, after 1 month, in a renewed negative crude zinc balance and a regression of immune functions. Both the zinc pool and immunological parameters were restored by 30 further days of MEL treatment. The existence of a significant correlation between zinc and thymic hormone after both cycles of MEL treatment clearly shows an involvement of the zinc pool in the immunoenhancing effects of MEL and thus suggests an inter-relationship between zinc and MEL in px mice. Moreover, the existence of significant positive correlations between zinc or thymulin and interleukin-2 suggests that interleukin-2 may participate in the action of MEL, via zinc, on thymic functions in px MEL-treated mice.     

The effect of SDS, sodium dodecyl sulfate, on the metabolism and swimming capacity of Cyprinus carpio

Currently, diagnoses of attention deficit hyperactivity disorder (ADHD) and hyperkinetic disorder (HKD) are made on the basis of phenomenology, but information is accumulating from the neurosciences about the biological bases of these disorders. Recent studies addressing the neuropsychology, neuroanatomy, neurochemistry, and molecular biology of ADHD/HKD document abnormalities in well-defined neuroanatomical networks and neurochemical pathways. Magnetic resonance imaging (MRI) studies have shown that some regions of the frontal lobes (anterior superior and inferior) and basal ganglia (caudate nucleus and globus pallidus) are about 10% smaller in ADHD groups than in control groups of children, and molecular genetic studies have shown that diagnosis of ADHD is associated with polymorphisms in some dopamine genes (the dopamine D4 receptor gene and the dopamine transporter gene).     

利用模糊综合评价法确定矿山生产规模

矿山生产规模是矿山开发过程中一项非常重要的决策要素。文中利用模糊综合评价方法综合考虑矿山生产的多种因素，对矿山生产规模的确定作了有益的探索，并建立了焦家金矿技术改造生产规模确定的模糊综合评价模型。     

Chronotropic competence in endurance trained heart transplant recipients: heart rate is not a limiting factor for exercise capacity

Soy isoflavones are hypothesized to be responsible for changes in hormone action associated with reduced breast cancer risk. To test this hypothesis, we studied the effects of isoflavone consumption in 14 premenopausal women. Isoflavones were consumed in soy protein powders and provided relative to body weight (control diet, 10 +/- 1.1; low isoflavone diet, 64 +/- 9.2; high isoflavone diet, 128 +/- 16 mg/day) for three menstrual cycles plus 9 days in a randomized cross-over design. During the last 6 weeks of each diet period, plasma was collected every other day for analysis of estrogens, progesterone, LH, and FSH. Diet effects were assessed during each of four distinctly defined menstrual cycle phases. Plasma from the early follicular phase was analyzed for androgens, cortisol, thyroid hormones, insulin, PRL, and sex hormone-binding globulin. The low isoflavone diet decreased LH (P = 0.009) and FSH (P = 0.04) levels during the periovulatory phase. The high isoflavone diet decreased free T3 (P = 0.02) and dehydroepiandrosterone sulfate (P = 0.02) levels during the early follicular phase and estrone levels during the midfollicular phase (P = 0.02). No other significant changes were observed in hormone concentrations or in the length of the menstrual cycle, follicular phase, or luteal phase. Endometrial biopsies performed in the luteal phase of cycle 3 of each diet period revealed no effect of isoflavone consumption on histological dating. These data suggest that effects on plasma hormones and the menstrual cycle are not likely to be the primary mechanisms by which isoflavones may prevent cancer in premenopausal women.     

An evaluation of the iatrosedative process for treating dental fear

The iatrosedative process is an interpersonal-cognitive technique by which fearful patients are calmed by the behavior, attitude, and communicative stance of the dentist. The process consists of an iatrosedative interview and a clinical encounter. In our study, 58 fearful dental patients were assigned to 1 of 3 treatment groups. The Corah Dental Anxiety Scale was administered at admission to the clinic, immediately after the iatrosedative interview or standard interview, and again after the first and second clinical encounters. Participants who received the iatrosedative interview had a significantly greater reduction in dental anxiety after the interview than those who received the standard interview. After the two clinical encounters, however, the difference in anxiety reduction between the two groups was not significant. In addition, there was no significant difference in anxiety reduction between iatrosedative participants who had the same dentist for both the interview and the clinical encounter and participants who had different dentists for each part of the study. It is concluded that an iatrosedative interview is more effective than a standard dental interview in decreasing anxiety.     

Monoamine oxidase activity in the brain of male laboratory mice differing in the capacity for social dominance

The activity of type A and B monoamine oxidases (MAO-A and MAO-B) was studied in the brain stem and cerebral hemispheres of male mice from the PT and CBA inbred laboratory lines with opposite dominance capabilities and in their direct and reciprocal F1 hybrids. MAO-B activity was shown to be lower in the hemispheres of intact PT males and F1 hybrid males, which are genetically predisposed to social domination, than in CBA males. One-hour social stress imposed by grouping mice into a micropopulation resulted in a decrease in MAO-A and MAO-B activity in the hemispheres of dominant PT and F1 hybrid males and an increase in MAO-B activity in the brain stem of subordinant CBA and dominant F1 males.