Novel mechanisms of neuroprotective effects of Quercetin on human striatal neuroblasts

Human striatal precursor (HSP) primary cell cultures were isolated from ganglionic eminence of 9-12 week old human fetuses and extensively characterized in vitro (1). Our studies demonstrated that these cultures consists of a mixed population of neural stem cells, neuronal-restricted progenitors and striatal neurons that express and are responsive to many trophic factors, as BDNF and FGF2, and possess an adaptive response to stress conditions as nutrient deprivation and hypoxia through mechanisms involving different factors and neurotrophins (1,2). In the last decades, several in vitro and in vivo studies have provided evidence for neuroprotective effects by Quercetin, a polyphenol widely present in nature, passively absorbed in the small intestine and able to traverse the blood brain barrier (3). However, the mechanisms through which Quercetin exerts its neuroprotective effects are not fully delucidated. Our study was aimed at investigating the effects of Quercetin on HSP cells and its contribution to cell survival in nutrient deprivation condition, obtained replacing culture medium with Phosphate Buffer Saline (PBS). Quercetin treatment significantly promoted cell survival and strongly decreased apoptosis induced by nutrient deprivation condition, as evaluated by MTT assay, Trypan Blue staining and western blot analysis of cell death and proliferation markers. Moreover, since the adhesive capacities of cells are essential for cell survival, we next analysed the expression of some adhesion molecules such as Pancadherin and Focal Adhesion Kinase; our results interestingly showed that PBS exposure determined a strong decrease in all the analysed adhesion molecules, while in presence of Quercetin the expression was significantly increased. Our results add new mechanicistic insights into the comprehension of neuroprotective action of Quercetin treatment, thus suggesting possible implications in sustaining striatal neuron survival during neurodegenerative disorders, such as Huntington Disease

Movement related brain macropotentials and skilled motor actions

Background: Movement Related Brain Macropotentials (MRBMs) are electrical brain potentials occurring before, during and after skilled movements. Specific components of these potentials have been described and it has been reported that they can be recorded also during mental motor imagery and can be influenced by practice. To understand the exact relationship between MRBMs and skilled actions and to verify the hypothesis that motor training could modify MRBMs profile and influence specific components an experiment has been performed in which MRBMs were recorded during the execution of different skilled performance tasks and before and after a period of training. Methods: The experiment has been carried out with 31 healthy male subjects, divided into three groups. Eleven performed the Alert test (A), a simple reaction time test, in which the subject had to press in a precise sequence three keys of a keyboard when a figure appeared on the computer monitor. Ten subjects performed the Choice test (CH), a complex reaction time test, in which they had to press the three keys in a different order when one of two different figures appeared randomly on the screen. Ten subjects performed the Choice test with the addition of a Go/No-Go paradigm (CHNG) in which participants had also to repress an unsuitable response. All subjects were tested before and after 10 days of training. During the trials EEG, EMG and other physiological parameters were recorded. The time of the recorded test was divided into three periods: prestimulus, motor (premotor, motor action, motor completion) and postmotor. Data were collected, averaged and compared by appropriate statistical methods. Results: The time of EMG activation and Reaction Time (RT) were lower in A then in CH and CHNG. Training did not influenced A, but was followed by a significant reduction of RT in CH and CHNG. The profile of MRBMs was different in the motor period in the three tests. The duration of Premotor Potential (PMP), a positive wave recorded in the premotor component of the motor period, increased passing from A to CHNG, but after training, it was reduced only in the CHNG test. During motor action the duration of the negative wave Motor Cortex Potential (MCP) increased from A to CHNG and was reduced after training in all tests. In CHNG training reduced the latency of N1 and N2, the negative peaks recognizable in the MCP profile, and the latency of the Skilled Performance Positivity (SPP), a wave occurring in the postmotor period. Moreover, after training the period preceding the stimulus showed an increase of negativity in the last 200 msec. Conclusions: MRBMs can change their profile in relation to the characteristics of the test and the skilled motor action. The increase of duration and latency of the motor period waves, passing from A to CHNG, can be considered as picture of increased information processing and response selection brain activity. Moreover, training can affect the profile of the waves, reducing their duration and latency, particularly when the performance requires high mental effort. © 2009 by Nova Science Publishers, Inc

Attention in athletes of high and low experience engaged in different open skill sports

In this study were examined differences in attentional style of athletes engaged in two open skill sports requiring high reactivity (karate and volleyball) in groups with high or low experience. 42 healthy men, 24 volleyball players, 12 of High Experience (first division Italian League players whose M age was 28 yr. (SD=5) and 12 of Low Experience (prejunior Italian team athletes whose M age was 19 yr. (SD= 2). and 18 karateka, 9 of High Experience (3rd and 4th dan black belt athletes whose M age was 31 yr., SD=5) and 9 of Low Experience (1st and 2nd dan black belt karateka whose M age was 32 yr., SD=5). Tests involved different types of attention: Alert, Go/No-Go, Divided Attention, and Working Memory. For each one, the reaction time (RT), variability, change in RT, and number of errors were analysed. Karateka of High Experience reacted faster than those of Low Experience on the simple RT test, Alert (M RT: 204 vs 237 msec., p< .01), while on the Divided Attention test, the High Experience subjects performed more poorly and committed more errors (M errors: 4.89 vs 1.44, p <.003). Young volleyball players of Low Experience reacted faster than colleagues of High Experience on the Alert (M RT: 187 vs 210 msec., p<.01) and Divided Attention tests (M RT: 590 vs 688 msec., p<.001) but committed more errors (Divided Attention test, M errors: 6.50 vs 3.08, p<.007). For the Divided Attention and Working Memory tests, correlations were positive among errors, RT, and RT variability but only for volleyball athletes of High Experience, suggesting they showed higher attention and stability in complex reactions than the group with Low Experience. No significant correlations were noted for either group of karateka on complex reactions. Results suggested that the attentional resources were engaged in different ways in the two groups of athletes and, in each group, there were differences between persons of High and Low Experience

Hormonal changes after supine posture, immersion, and swimming

This study was undertaken to evaluate the effects of the supine posture, immersion, and swimming on hormones involved in the regulation of hydrosaline equilibrium. Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), plasma renin activity (PRA), and aldosterone (ALDO) were measured by radioimmunoassay in eight untrained young subjects (five males and three females). Blood samples were collected on different days: control morning samples in a relaxed standing posture before each test; after 20 min in a supine position; after 20 min of horizontal immersion in water at 28 degrees C; after 20 min of backstroke swimming (speed about 1 m/s). No changes occurred in AVP levels after each test. ALDO and PRA increased significantly only after swimming and were directly correlated. ANP increased significantly after immersion, but no further increase was observed after swimming. The hematocrit, which increased after swimming, was inversely correlated with ANP levels in the post-exercise samples. These data show that while ALDO and PRA increase only in response to swimming, even at moderate intensity, ANP probably requires more prolonged and intense exercise to reach a significantly higher level than in immersion

Hormonal and metabolic effects following a football match

Hormonal and metabolic parameters were studied for two teams after a football match. Blood samples were collected before the start, at half-time, at the end, and 45 and 90 min after the end of the game. In the first team, ACTH, cortisol, and lactate levels increased significantly during the whole match to resume basal levels in the fourth sample (45 min after the end of play). HGH, prolactin, and blood glucose were found to be increased only at half-time. The second team had an intense and long warm-up period before the match and the lactate concentrations were already elevated in the first sample. All the other parameters, except ACTH and glucose, displayed a pattern similar to that of the first team. The differences in the time courses of the hormonal and metabolic values are discussed

Changes in the exercise-induced hormone response to branched chain aminoacids administration

It was the aim of the present experiment to detect possible effects of branched-chain amino acids (BCAA) on the endocrine response to 1 h of continuous running. Blood samples were collected from 14 long-distance runners (age 24-42 years) in two different trials performed at 1-week intervals. In both trials (E and P) blood samples were collected at the following times: 9 a.m. (basal values sample), 10.30 a.m. (sample 90), 11.30 a.m. (sample 150), 12.30 p.m. (sample 210); the athletes performed 1 h of running at a constant predetermined speed between samples 90 and 150. Following the basal sample a mixture containing BCAA (E trial), or not containing BCAA (P trial) was ingested. In both trials no hormone basal concentrations, except insulin, were changed before exercise. In P trial, following exercise (sample 150), human growth hormone (HGH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol (C) increased, while testosterone (T) decreased. In sample 210, after 1 h of rest, while ACTH, PRL and HGH had recovered to basal concentrations, C remained elevated and T displayed a further decrease. In the E trial a similar pattern of change was observed in sample 150 for HGH, PRL, ACTH and C; in sample 210 HGH and PRL displayed significantly lower values than in the corresponding P trial samples. The T was not modified by the running exercise and increased during the recovery period. It is, therefore, suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and

Internal-external motor imagery and skilled motor actions

The purpose of this study was to analyze the movement-related brain macropotentials (MRBMs) recorded during the executions of two tests of motor imagery: kinaesthetic (internal) and visual (external).Recordings were compared with those obtained performing a GO/NO-GO motor test. The GO test required pressure of three keys of a modified keyboard in sequence when a figure appeared in the computer screen. On No/GO trials no button had to be pressed. Motor imagery tests were an internal or kinaesthetic imagination test (IN MI) on which partecipants imagined performing the pressure of keyboard buttons, avoiding any real movement, and an external or visual imagination test (EX MI) on wich subjects were asked to imagine seeing their finger press the buttons. With the completion of the Movement Imagery Questionnaire, the partecipants were assigned into two groups: high (11) and low (10) capacity of imagination. The experimental data confirm that real motor activity is related to higher amplitude MRBMs than motor imagery. The profile of the waves recorded during internal imagery seems to be related to a higher brain involvement compared to those recorded during external visual imagery; it suggest that the kinaesthetic process of imaginations is more efficient in information processing and motor skill acquisition

Influence of training on the response of androgen plasma concentrations to exercise in swimmers

In eight top-level male endurance swimmers the aerobic performance and the response to exercise of total testosterone (T), free testosterone (fT), sex hormone binding globulin (SHBG), non-SHBG-bound testosterone (NST) and cortisol (C) were evaluated during a training season. The swimmers participated in three test sessions which occurred 6, 12 and 24 weeks after the beginning of the season. During each session, after a standard warm-up, the swimmers performed a set of 15 x 200-m freestyle, with a 20-s rest between repititions, at a predetermined individual speed. Three blood samples were collected: before warm-up, at the end of the set, and after 1 h of recovery. A few days before each session, the individual swimming velocity associated with a 4 mmol.l-1 blood lactate concentration (v4) was assessed as a standard of aerobic performance. The values of v4 were lower in the second session than in the third one. The concentrations of C. which increased after the exercise, showed the highest values in the second session. The values of T and the T:SHBG ratio increased after the exercise but returned to their initial concentrations during the recovery period. The values of fT and NST increased after the exercise in the first and third sessions. In the initial two sessions, when the aerobic performance was still low, the concentrations of NST decreased to below the initial values after recovery. In session III, when the adaptation to the training workload was complete, NST returned to resting concentrations after recovery. The results would suggest that stressful stimuli produced by an increase in training volume may induce changes in androgen metabolism during exercise. In this respect, NST would appear to be a better index of metabolic response than T, T/SHBG and fT