Exercise combined with a probiotics treatment alters the microbiome, but moderately affects signalling pathways in the liver of male APP/PS1 transgenic mice.

It has been demonstrated that physical exercise and probiotic supplementation delay the progress of Alzheimer's Disease (AD) in male APP/PS1TG mice. However, it has also been suggested that both exercise and AD have systemic effects. We have studied the effects of exercise training and probiotic treatment on microbiome and biochemical signalling proteins in the liver. The results suggest that liver is under oxidative stress, since SOD2 levels of APP/PS1 mice were decreased when compared to a wild type of mice. Exercise training prevented this decrease. We did not find significant changes in COX4, SIRT3, PGC-1a or GLUT4 levels, while the changes in pAMPK/AMPK, pmTOR/mTOR, pS6/S6 and NRF2 levels were randomly modulated. The data suggest that exercise and probiotics-induced changes in microbiome do not strongly affect mitochondrial density or protein synthesis-related AMPK/mTOR/S6 pathways in the liver of these animals.

Changes in physical fitness of Hungarian college students in the last fifteen years.

This study compared the physical fitness of Hungarian undergraduate students in 2011-2012 with the representative sample surveyed in 1997-1998. A total of 123 males and 309 females (mean age 21.19 ± 2.19 yrs) were randomly selected in two Hungarian universities (Pécs, Kaposvár). Anthropometric data (height, weight, skinfolds, body fat percentages) were measured and the subjects performed 9 tests of the Eurofit Fitness Test Battery. The BMI, total body fat and performance in most of the fitness components (balance, agility/speed, flexibility, abdominal muscular strength, aerobic fitness of females) was higher in 1997-1998 (p<0.05) whereas the handgrip strength and performance in Bent Arm Hanging test were significantly better in 2011-2012 (p<0.001). These findings support interventions focusing on increasing regular physical activity among Hungarian youth.

Investigation of Factors Related to Sport-Specific Compulsory Element Execution in Artistic Swimming.

Artistic swimming is an Olympic sport requiring a high level of fitness, as well as technical skills, artistry, flexibility, a good sense of rhythm, remarkable lung capacity and physical strength. The artistic swimming of adolescents has been largely untouched by the scientific community, so training this group based on scientific data is difficult. Due to the gap between theoretical knowledge and practical application, this study aimed to measure the technical elements, strength parameters, and swimming performance of young artistic swimmers and to compare swimming performance and strength with the quality of artistic element performances. Hungarian female junior artistic swimmers (14.36 ± 1.01 year) participated in this study. Swimming tests were performed, and three basic elements (body boost, barracuda, and vertical position) were scored. A negative correlation was found between 100 m freestyle swimming times and vertical position scores, as well as between 50 m breaststroke leg swimming times and body boost scores. Moreover, three months of breaststroke leg swim training resulted in improvements in body boost performance. In addition, a positive correlation was found between mean hand grip strength and barracuda scores, as well as between vertical position scores. According to the results of three months of breaststroke leg training, swimming practice improves artistic swimming performance by itself. A correlation was found between strength parameters and the execution of synchro elements, showing the importance of complex training strategies in this sport.

Nutritional Habits of Hungarian Older Adults.

There are many nutritional changes that come with aging, mostly as consequences of health regression. Malnutrition and overweight often start with inadequate food consumption, followed by alterations in biochemical indices and body composition. In our study, we aimed to analyze the feeding habits and energy and nutrient intake of a Hungarian elderly population, focusing on macronutrient, water, fruit, and vegetable consumption while searching for possible nutritional factors leading to NCD and many other chronic diseases in this population. Two questionnaires were used. These were the Mini Nutritional Assessment (MNA) and one asking about nutritional habits, and a 3-day feeding diary was also filled. Subjects (n = 179, 111; females (F), 68 males (M), older than 50 years were recruited. Based on MNA results, 78 adults (43.57% of the studied population) were malnourished or at risk of malnutrition, although, according to BMI categories, 69% were overweight and 7.3% were obese among M, while 42.3% were overweight among F. The average daily meal number was diverse. The amount of people consuming fruit (11.7%) and vegetables (8.93%) several times a day was extremely low (15.3% of F and 4.4% of M). Daily fruit consumption in the whole sample was 79.3%. Overall, 36.3% consumed 1 L of liquid and 0.5 L of consumption was found in 15.1% of participants. A significant gender difference was found in water consumption, with F drinking more than M (p ≤ 0.01). In our sample, 27.93% of the respondents took dietary supplements. Further analysis and research are needed to explore the specific health implications of and reasons behind these findings.

Assessment Tools Measuring Fundamental Movement Skills of Primary School Children: A Narrative Review in Methodological Perspective.

This paper aimed to analyze fundamental movement skill (FMS) assessment tools that could be used for primary school children. In this narrative review, the Motoriktest für Vier- bis Sechjärige Kinder (MOT 4-6), Movement Assessment Battery for Children-2 (M-ABC-2), Motorische Basiskompetenzen (MOBAK) Körperkoordinationtest für Kinder (KTK), Test of Gross Motor Development (TGMD), Maastricht Motoriek Test (MMT) and the Bruininks-Oseretsky Test of Motor Proficiency-2 (BOT-2) were analyzed from a methodological perspective, such as the number of test items, tools and types of tests, in terms of the FMS area. The analysis revealed that to assess locomotor movement skills, the BOT-2 has an excellent test for running ability, but for detecting technical difficulties, the TGMD is recommended. To test hopping, the MMT is the best test. Object control movement skills are measured with throws, dribbles and catches. Most of the tools assessed these skills, but it turned out that the TGMD is the best for measuring object control. Stability movement skills are tested with static and dynamic balance tests. Dynamic balance is more frequently used, and the MOT 4-6, KTK and BOT-2 have the most tools to use. However, the MMT is an excellent test for static balance. Fine motor movement skills are easy to assess with the MMT and MOT 4-6, since they have low equipment requirements. The BOT-2 is the best measurement tool; however, it has high equipment requirements. All of the FMS assessment tools are good; however, we concluded that although these tools are excellent for research purposes, they are difficult to apply in a school setting. Thus, teachers and coaches are advised to always select a single task from the available assessment tools that is appropriate for the skills they would like to measure.

Glial cells in the central nervous system of earthworm, Eisenia fetida.

Glial elements in the central nervous system of Eisenia fetida were studied at light- and electron microscopic level. Cells were characterized with the aid of toluidine blue, Glial Fibrillary Acidic Protein (GFAP), S100 staining. We identified neurilemmal-, subneurilemmal-, supporting-nutrifying- and myelinsheath forming glial cells. Both neuronal and non-neuronal elements are S100-immunoreactive in the CNS. Among glial cells neurilemmal and subneurilemmal cells are S100-immunopositive. With the antibody against the S100 protein one band is visible at 15 kDa. GFA P-immunopositive supporting-nutrifying glial cells are localized around neurons and they often appear as cells with many vacuoles. GFA P-positive cell bodies of elongated neurilemmal glial cells are also visible. Western blot analysis shows a single 57 kDa GFA P immunoreactive band in the Eisenia sample. At ultrastructural level contacts between neuronal and glial cells are recognizable. Glial cell bodies and their filopodia contain a granular and vesicular system. Close contacts between neuronal cell membranes and glial filopodia create a special environment for material transport. Vesicles budding off glial cell granules move towards the cell membranes, probably emptying their content with kiss and run exocytosis. The secreted compounds in return may help neuronal survival, provide nutrition, and filopodia may also support neuronal terminals.

Comparison of blood and saliva lactate level after maximum intensity exercise.

Several studies have described high correlation of salivary and blood lactate level during exercise. Measuring the effectiveness and intensity of training, lactate concentration in blood, and lately in saliva are used.The aim of our study was to evaluate the correlation between the concentration and timing of salivary and blood lactate level in endurance athletes and non-athletes after a maximal treadmill test, and to identify physiological and biochemical factors affecting these lactate levels.Sixteen volunteers (8 athletes and 8 non-athletes) performed maximal intensity (Astrand) treadmill test. Anthropometric characteristics, body composition and physiological parameters (heart rate, RR-variability) were measured in both studied groups. Blood and whole saliva samples were collected before and 1, 4, 8, 12, 15, 20 min after the exercise test. Lactate level changes were monitored in the two groups and two lactate peaks were registered at different timeperiods in athletes. We found significant correlation between several measured parameters (salivary lactate - total body water, salivary lactate - RR-variability, maximal salivary lactate - maximal heart rate during exercise, salivary- and blood lactate -1 min after exercise test). Stronger correlation was noted between salivary lactate and blood lactate in athletes, than in controls.

Well-Trained Elders Have Antioxidant Responses and an Equal Magnitude of EIMD as Young Adults.

Aim The aim of the study was to investigate acute and chronic effects of a two-week eccentric concentric, dynamometric training concerning the time-course changes of blood antioxidant parameters (total antioxidant capacity, catalase enzyme activity, thiol concentration), and to compare the adaptability of young and older muscle to this type of training. Methods Seventeen moderately trained young and older men participated in this research. Subjects performed six eccentric concentric exercise bouts during the training period and maximal voluntary isometric contraction torque, plasma CK and intensity of muscle soreness were determined before and 24 h after the first exercise. During five testing sessions (baseline, 24 h, 48 h, week 1, week 2) the level of blood antioxidants were measured. Results No significant changes were registered in total antioxidant capacity and catalase enzyme activity for any time points; furthermore, no difference was found between groups during the training period. However, total thiol concentrations measured two weeks after the first exercise bout significantly differed between the young and elderly groups. Plasma CK and the subjective intensity of soreness elevated significantly 24 h following the first training, while maximal voluntary isometric contraction torque decreased at the same time. Conclusions Our results do not support previous findings that chronic, short-term eccentric concentric training programs enhance the antioxidant defense of well-trained older and young men. This type and setting of exercise did not cause a different time course of changes in the markers of exercise-induced muscle damage (EIMD) in the studied population. Subjects may already have adapted to maintain constant levels of antioxidants and isometric torque due to their active lifestyle.

Neuro-immune interactions in the dove brain.

Mast cells (MC) are of hematopoetic origin. Connective tissue type MCs are able to function in IgE dependent and independent fashion, change their phenotype according to the tissue environment. They are able to enter the brain under normal physiological conditions, and move into this compact tissue made of neurons. In doves MCs are found only in the medial habenula (MH) and their number is changing according to the amount of sex steroids in the body. MCs are able to synthesize and store a great variety of biologically active compounds, like transmitters, neuromodulators and hormones. They are able to secrete GnRH. With the aid of electron microscopy we were able to describe MC-neuron interactions between GnRH-positive MCs and neurons. Piecemeal degranulation (secretory vesicles budding off swollen and active granules) seems to be a very efficient type of communication between MCs and surrounding neurons. Different types of granular and vesicular transports are seen between GnRH-immunoreactive MCs and neurons in the MH of doves. Sometimes whole granules are visible in the neuronal cytoplasm, in other cases exocytotic vesicles empty materials of MC origin. Thus MCs might modulate neuronal functions. Double staining experiments with IP3-receptor (IP3R), Ryanodine-receptor (RyR) and serotonin antibodies showed active MC population in the habenula. Light IP3R-labeling was present in 64-97% of the cells, few granules were labeled in 7-10% of MCs, while strong immunoreactivity was visible in 1-2% of TB stained cells. No immunoreactivity was visible in 28-73% of MCs. According to cell counts, light RyR-positivity appeared in 27-52%, few granules were immunoreactive in 4-19%, while strong immunopositivity was found only in one animal. In this case 22% of MCs were strongly RyR-positive. No staining was registered in 44-73% of MCs. Double staining with 5HT and these receptor markers proved that indeed only a part of MCs is actively secreting. Resting cells with only 5HT-immunopositivity are often visible. The activational state of MCs is changing at higher estrogen/testosterone level, thus with the secretion of neuromodulators they might alter sexual and parental behavior of the animals.

Effects of Caffeine and Caffeinated Beverages in Children, Adolescents and Young Adults: Short Review.

The prevalence of ED consumption has increased over the past 10-15 years. Studies describing the effects of caffeine and caffeinated beverages show confusing results, so it seems important to regularly summarize the available facts, and in more detail. By a thorough analysis of more than 156 scientific papers, the authors describe the molecular background of absorption, as well as the positive and negative effects of different dosages of caffeine, just like its effects in physical activity and performance. ED and EDwA consumption is a regular habit of not only adults, but nowadays even of children and adolescents. There are no safe dosages described of caffeine or ED consumption for children. There are no positive short- or long-term effects of these compounds/products concerning developing brain functions, psycho-motor functions, or social development. Instead, there are many unpleasant side effects, and symptoms of regular or higher-dose ED consumption, especially at younger ages. This mini review describes many details of these unpleasant side effects, their severity, and motivations for consuming these compounds/products. In a quantitative research in Hungary (10-26 years, mean age: 15.6 ± 3.8 y, 1459 subjects, randomly chosen population), a survey based on a questionnaire asking people about their ED consumption habits was conducted. According to the data, 81.8% of the participants consumed EDs at least once, and 63.3% tried several products of the kind. A positive correlation was found between age and consumption (p < 0.001). The results show that a high proportion of this group often consumed EDwA, in many cases leading to harmful side-effects of caffeine overdose. In a sample of Hungarian high school and college students (17-26 years), ED consumption matched the international data, and only 19.7% of respondents did not use EDs at all (had never tasted an ED in their life).

Relationship between Anthropometric, Physical and Hormonal Parameters among Pre-Pubertal Handball Players.

BACKGROUND: The aims of our study were to investigate the changes in anthropometric and physical parameters and fasting hormonal levels among pre-pubertal female handball players (n = 14, age: 11.53 ± 0.58 yrs, height: 153.36 ± 5.12 cm, body mass: 43.59 ± 6.14 kg) in the pre-season period following 8 weeks of handball training, and to analyze the contribution of hormones, physical performance and anthropometric parameters. METHODS: Prior to and immediately following the training period, several anthropometric, strength, and cardiorespiratory variables, including fasting hormonal concentrations (plasma cortisol, estradiol, testosterone and growth hormones) were measured. Athletes performed concurrent resistance and aerobic exercises, including game-based trainings during the 8-week training period. RESULTS: Significant elevations were found in all strength parameters (maximal handgrip strength dominant (D): 16.40%, p < 0.01; non-dominant (ND): 25.15%, p < 0.05; maximal concentric (MVC) torque of quadriceps D: 13.82%, p < 0.05; ND: 12.61%, p < 0.05; MVC torque of hamstring D: 12.14%, p < 0.01; ND: 12.44%, p < 0.01), including plasma cortisol levels (C, 34.30%, p < 0.05) and peak respiratory quotient (5.24%, p < 0.05). Body composition and maximal oxygen uptake (VO2max) remained unchanged. Percentage changes in thigh (r = 0.316, p < 0.05), hand (r = 0.361, p < 0.05), and hip circumference (r = 0.297, p < 0.05) correlated with C changes. Percentage changes in plasma growth hormone levels (GH) contributed to the magnitude of gains in handgrip strength (r = 0.553, p < 0.05). Percentage changes in maximal exercise pulmonary ventilation (MVE) correlated with elevated C (r = -0.592, p < 0.05). DISCUSSION: Changes in anthropometric variables and fasting hormone levels (estradiol, testosterone and cortisol) were poor indicators of developing VO2max and strength during pre-pubertal years. Physical adaptation may not be explained in consideration of the athletes' hormonal or anthropometric characteristics. CONCLUSION: Gradually increased training volume followed by a summer break should be applied to youth handball, considering the anti-hypertrophic responses and the inhibitory effect of elevating C on pre-pubertal maturation.

Corrigendum: Physical Activity as a Preventive Lifestyle Intervention Acts Through Specific Exosomal miRNA Species-Evidence From Human Short- and Long-Term Pilot Studies.

[This corrects the article DOI: 10.3389/fphys.2021.658218.].

Physical Activity as a Preventive Lifestyle Intervention Acts Through Specific Exosomal miRNA Species-Evidence From Human Short- and Long-Term Pilot Studies.

Exercise initiates systemic adaptation to promote health and prevent various lifestyle-related chronic diseases. Emerging evidence suggests that circulating exosomes mediate some of the beneficial effects of exercise via the transfer of microRNAs between tissues. Yet to date, a comprehensive profile of the exosomal miRNA (exomiR) content released following short-term (0.5 year in this study) and long-term (25 + years in this study) regular bouts of exercise is still lacking. However, a better understanding of these miRNA species would assist in clarifying the role of regular exercise at the molecular level in the prevention of chronic diseases. In the present pilot studies we analyzed serum exomiR expression in healthy young, sedentary participants (n = 14; age: 23 ± 2 years) at baseline and following a half year-long moderate-intensity regular exercise training. We also analyzed serum exomiR expression in older, healthy trained participants (seniors, n = 11; age: 62 ± 6 years) who engaged in endurance activities for at least 25 years. Following the isolation and enrichment of serum exosomes using Total Exosome Isolation Reagent (TEI) their exomiR levels were determined using the amplification-free Nanostring platform. Hierarchical cluster analysis revealed that the majority of exomiRs overlap for short-term (0.5 year in this study) and long-term (25 + years in this study) regular bouts of exercise. The top 12 significantly altered exomiRs (let-7a-5p; let-7g-5p; miR-130a-3p; miR-142-3p; miR-150-5p; miR-15a-5p; miR-15b-5p; miR-199a-3p; miR-199b-3p; miR-223-3p; miR-23a-3p, and miR-451a-3p) were used for further evaluation. According to KEGG pathway analysis a large portion of the exomiRs target chronic diseases including cancer, neurodegenerative and metabolic diseases, and viral infections. Our results provide evidence that exosomal miRNA modulation is the molecular mechanism through which regular exercise prevents various chronic diseases. The possibility of using such exomiRs to target diseases is of great interest. While further validation is needed, our comprehensive exomiR study presents, for the first time, the disease-preventive molecular pattern of both short and long-term regular exercise.

Energy Drink Consumption, Depression, and Salutogenic Sense of Coherence Among Adolescents and Young Adults.

The prevalence of energy drink consumption has increased in Hungary over the past 10-15 years. This study assesses the frequency, motivations, and adverse effects of energy drink consumption, and examines how the process of becoming a regular consumer is connected with sense of coherence and depression symptoms. A total of 631 high school and college students were assessed using the Depression Scale (BDS-13) and Sense of Coherence Scale (SOC-13). Logistic regression models were fit to test the effect of and links between factors influencing addiction to energy drink use. A total of 31.1% (95% CI: 27.4-34.7) of those surveyed consumed energy drinks, 24.0% of those affected consumed the energy drink with alcohol, 71.4% (95% CI: 64.7-77.3) experienced adverse effects following energy drink consumption, and 10.2% (95% CI: 6.7-15.2) experienced at least four symptoms simultaneously. The most common motivations of consumption were fatigue, taste, and fun. Obtained by multivariate logistic regression models, after adjustment for sex and age, SOC and tendency to depression had a significant influence on the respondents' odds of addiction. The tendency to depression increases the chances of addiction, while a strong sense of coherence diminishes the effects of depression. Young people in Hungary have been shown to consume energy drinks in quantities that are detrimental to their health. Complex preventive measures and programs are needed to address the problem. Families and educators should strive to instill a strong sense of coherence in children from an early age.

Artificial Neural Network Correlation and Biostatistics Evaluation of Physiological and Molecular Parameters in Healthy Young Individuals Performing Regular Exercise.

Studies support that regular physical activity (PA) decelerates senescence-related decline of physiological and molecular parameters in the elderly. We have addressed the other end of this spectrum: healthy and young, inactive individuals participated in a 6-month long personal trainer-guided lifestyle program. We have measured physiological and molecular parameters (differentiating high- and low responders) and their correlation with PA (sedentary status). Cluster analysis helped to distinguish individuals with high- or low PA and differentiate high- and low-responders of each parameter. The assessed cardiovascular parameters (heart rate, blood pressure, 6-min walking distance, relative VO2max), body composition parameters (body fat and muscle mass percentage) metabolic parameters (glucose, insulin, HDL, LDL), immune parameters (cortisol, CRP, lymphocyte counts, hTREC) all showed improvement. Artificial neural network analysis (ANN) showed correlation efficiencies of physiological and molecular parameters using a concept-free approach. ANN analysis appointed PA as the mastermind of molecular level changes. Besides sedentary status, insulin and hTREC showed significant segregation. Biostatistics evaluation also supported the schism of participants for their sedentary status, insulin concentration and hTREC copy number. In the future ANN and biostatistics, may predict individual responses to regular exercise. Our program reveals that high responder individuals of certain parameters may be low responders of others. Our data show that moderate regular PA is essential to counteract senescence in young and healthy individuals, despite individual differences in responsiveness. Such PA may not seem important in the everyday life of young and healthy adults, but shall become the base for healthy aging.

Body fat of rats of different age groups and nutritional states: assessment by micro-CT and skinfold thickness.

Obesity presents a growing public health problem. Therefore the analysis of body composition is important in clinical practice as well as in animal research models of obesity; hence precise methods for the assessment of body fat would be essential. We aimed to evaluate in vivo abdominal microcomputed tomography scan restricted to the L1-L3 region [micro-CT(L1-L3)], a skinfold thickness-based method (STM), and postmortem body composition analysis (PMA) with regard to whole body micro-CT scan in rats. Male Wistar rats of different age groups (from 3 to 24 mo) and nutritional states (normally fed, high-fat diet-induced obese, and calorie-restricted) were used. The fat percentage was determined with micro-CT(L1-L3) and whole body scan in anesthetized rats. Their skinfold thickness was measured in five locations with a Lange caliper. Wet weights of epididymal and retroperitoneal fat pads were determined via PMA. With regard to fat mass, the strongest correlation was observed between abdominal and whole body micro-CT. The other methods showed weaker associations with whole body micro-CT and with each other. Micro-CT(L1-L3) and PMA showed similar age-associated increase in fat mass between 3 and 18 mo. Micro-CT(L1-L3), STM, and PMA were efficient to detect differences in fat mass values in groups of different nutritional states. Micro-CT(L1-L3) appears to be a useful method for body fat assessment in rats with reduced scanning time. In rats, STM may also be a useful, low priced, noninvasive, and simple in vivo technique to assess obesity. NEW & NOTEWORTHY Body fat of rats assessed by in vivo abdominal microcomputed tomography of the L1-L3 region strongly correlates with values determined by whole body scan. Therefore, it is a useful method for fat assessment with reduced scanning time. Skinfold thickness measurement is an in vivo technique to assess progression of obesity in rats.

Plasma Actin, Gelsolin and Orosomucoid Levels after Eccentric Exercise.

The present study investigated the acute effect of eccentric exercise on blood plasma actin, gelsolin (GSN) and orosomucoid (AGP) levels in untrained and moderately trained individuals, and their correlation with exercise induced muscle damage (EIMD) markers (CK, intensity of muscle soreness and maximal voluntary contraction torque deficit). Healthy physical education students (6 untrained, 12 moderately trained) participated in this research. Actin, GSN, AGP and CK levels were measured in blood plasma at baseline, immediately, 1 h, 6 h and 24 h post-exercise comprising 90 eccentric quadriceps contractions performed on a dynamometer. There was significant time main effect for GSN, AGP, CK and significant difference was found between baseline and the lowest value of post-exercise GSN (p < 0.05), as well as baseline and the highest value of post-exercise AGP (p < 0.05). Relationships were found between GSN levels and other indirect EIMD markers (between all GSN levels at post-exercise and CK activity at 6 h, p < 0.05; GSNMIN and muscle soreness at post-exercise, p < 0.04), GSN and AGP; however, actin did not correlate at any time points with GSN. Actin, GSN, AGP and CK responses after eccentric exercise do not seem sensitive to training status. The plasma actin level is used as an indicator of injury, however, our results suggest that it is not an accurate marker of EIMD, while plasma GSN concentrations show a better relationship with EIMD and the post-exercise inflammatory process. The elevated plasma AGP and the correlation between GSN and AGP seem to be promising for assessment of exercise-induced muscle injury.

Embryogenesis of the serotonergic system in the earthworm Eisenia fetida (Annelida, Oligochaeta): immunohistochemical and biochemical studies.

Organization of the serotonergic system and changes of the serotonin (5-HT) content were studied during the embryogenesis of the earthworm Eisenia fetida, using immunocytochemistry and HPLC. A gradual emergence of 5-HT immunoreactive (IR) cells and their axon projections in the several ganglia of the central (CNS) and peripheral nervous system are described in the context of a staged time-scale of development. The first 5-HT-IR neurons appear in the subesophageal ganglion at an early embryonic stage (E2), followed by neurons in some rostrally located ventral ganglia. In the cerebral ganglion, 5-HT-IR cells can be detected only from stage E5. The number of labeled cells in each ganglion of the embryo increases until hatching, when it is still considerably lower than that observed in adults. This shows that the development of the 5-HTergic system is far from complete by the end of embryogenesis. Organization of 5-HT-IR innervation of the body wall starts by stages E3 to E4. In the stomatogastric nervous system the first 5-HT-IR fibers can be detected by stage E5. By stage E9 5-HT immunopositive neurons can be observed in both the stomatogastric ganglia and the enteric plexus. Both 5-HT levels and the numbers of the labeled cells show a significant increase before hatching, which indicate a functional maturation of the 5-HTergic system. Based on the early appearance of 5-HT, we suppose that it may play a regulatory role in both the gangliogenesis and the maturation of peripheral functions necessary during postembryonic life.

Mast cells modulate maintained neuronal activity in the thalamus in vivo.

Single cell unit activity of 187 neurons of 24 rats were analysed to study the possible involvement of intracranial mast cells on modifying thalamic neuronal activity. Mast cells were activated with microiontophoretical application of compound 48/80. This substance did not modify the firing rate of cortical or hippocampal neurons (no mast cells are found here), however it caused excitation (70% in females, 11% in males), or inhibition (7% in females, 33% in males) on thalamic neurons, possibly due to mast cell activation. In consecutive anatomical evaluation many partially or fully degranulated mast cells were found in the recorded thalamic areas.

The application of in vivo microiontophoresis for the investigation of mast cell-neuron interactions in the rat brain.

Although mast cells are immune cells of hematopoietic origin, they can be found in parts of the central nervous system of many mammalian species. In the rat brain they are located in the thalamic region. Their function is not defined yet, although they are mostly known to secrete several chemicals, which may influence the surrounding neurons. There are no in vivo electrophysiological data available on the possible effects of brain mast cells on neurons. In this study, we used a combined method of microiontophoresis and extracellular single unit recording to simultaneously activate mast cells and record neuronal action potentials. Four-barrelled micropipettes were used for recording neuronal activity and for microiontophoretic application of mast cell degranulator Compound 48/80 (C48/80). Spike sorting routines were performed on-line and off-line to ensure that data were always recorded from a single neuron. C48/80 did not modify the firing rate of cortical neurons (no mast cells are found there), however, it caused excitation (n = 16/37, 43%), or inhibition (n = 9/37, 24%) in thalamic neurons possibly due to mast cell activation. Further investigations will clarify the biochemical nature of changes in neural excitability due to mast cell degranulation in the mammalian brain.