The functional aversive stimulus properties of several IP doses of (±)-amphetamine (1.25-10 mg.kg-1), 2-phenylethylamine (PEA, 2.5-10 mg.kg-1, following inhibition of monoamine oxidase with pargyline 50 mg.kg-1) and phenylethanolamine (6.25-50 mg.kg 1) were measured with the conditioned taste aversion (CTA) paradigm. A two bottle choice procedure was used, water vs. 0.1 % saccharin with one conditioning trial and three retention trials. (±)-Amphetamine and phenylethanolamine induced a significant conditioned taste aversion but PEA did not. (±)-Amphetamine and PEA increased spontaneous locomotor activity but phenylethanolamine had no effects on this measure. Measurement of whole brain levels of these drugs revealed that the peak brain elevation of PEA occurred at approximately 10 min whereas the peak elevations of (±)-amphetamine and phenylethanolamine occurred at approximately 20 min. The present failure of PEA to elicit conditioned taste aversion learning is consistent with previous reports for this compound. The differential functional aversive stimulus effects of these three compounds are surprising since they exhibit similar discriminative stimulus properties and both (±)-amphetamine and PEA are self-administered by laboratory animals. The present data suggest that time to maximal brain concentrations following peripheral injection may be a determinant of the aversive stimulus properties of PEA derivatives., A.J. Greenshaw, S. Turkish, B.A. Davis., and Obsahuje bibliografii
It is well known that the training level of a muscle belongs to the parameters that affect the H-reflex response amplitude. The aim of this study was to investigate the effects of training type on H- and T-reflex response parameters. For this purpose, 20 long-distance athletes (group I, test group), 18 short-distance athletes (group II, test group) and 20 non-trained subjects (group III, control group) were involved in this study in which the H- and T-reflex amplitude and latency values were measured. The H-reflex amplitude and latency values found in groups I, II and III were 3.64±0.28 mV and 26.88±1.45 ms, 3.17±0.26 mV and 26.19±1.89 ms, and 6.07±0.34 mV and 26.77±1.32 ms, respectively. The T-reflex amplitude and latency values of the groups I, II and III were 3.30±0.18 mV and 32.01±1.02 ms, 3.11±0.20 mV and 31.47±1.16 ms, 4.24±0.21 mV and 31.47±1.16 ms, respectively. There was no statistically significant difference between the groups with respect to latencies of H- and T-reflexes (p>0.05). In both test groups, the amplitudes of the H-reflex and T-reflex were significantly smaller than the control group (p<0.05). The results of this study suggest that training of muscles affect the H- and T-reflex response parameters., R. Ozmerdivenli, S. Bulut, T. Urat, A. Ayar., and Obsahuje bibliografii
Risk factors (RF) of cardiovascular diseases associated with modern lifestyle, such as stress, chronically increased blood pressure, hyperglycemia and dyslipidemia have a negative impact on the heart exposed to ischemia: their may facilitate its lethal injury (myocardial infarction) and occurrence of sudden death due to ventricular arrhythmias. On the other hand, some stressful stimuli related to RF including reactive oxygen species, transient episodes of ischemia (hypoxia), high glucose and other may play a dual role in the pathogenesis of ischemia/reperfusion (I/R) injury (IRI). Besides their deleterious effects, these factors may trigger adaptive processes in the heart resulting in greater resistance against IRI, which is also a characteristic feature of the female myocardium. However, sensitivity to ischemia is increasing with age in both genders. Current research indicates that comorbidity related to lifestyle may impair the cardiac response to acute ischemia not only by interference with pathophysiological mechanisms of IRI per se, but via suppression of intrinsic protective mechanisms in the heart and its ability to tolerate the ischemic challenges, although the role of RF has not been unequivocally proven. Moreover, even pathologically altered myocardium need not completely lose its adaptive potential. In addition, increased ischemic tolerance can be induced by the pleiotropic (independent of the primary) effects of some hypolipidemic and antidiabetic drugs, even in the diseased myocardium. This review addresses the issue of the impact of RF on cellular cardioprotective mechanisms and the possibilities to restore adaptive potential in subjects challenged with several RF. Reactivation of adaptive processes in the myocardium taking into consideration gender and age can contribute to optimalization of antiischemic therapy., T. Ravingerová, ... [et al.]., and Obsahuje seznam literatury
Common alimentary obesity frequently occurs on a polygenic basis as a typical lifestyle disorder in the developed countries. It is associated with characteristic complex metabolic changes, which are the cornerstones for future metabolic syndrome development. The aims of our study were 1) to determine the incidence of metabolic syndrome (based on the diagnostic criteria defined by the International Diabetes Federation for children and adolescents) in Czech obese children, 2) to evaluate the incidence of insulin resistance according to HOMA-IR and QUICKI homeostatic indexes in obese children with and without metabolic syndrome, and 3) to consider the diagnostic value of these indexes for the early detection of metabolic syndrome in obese children. We therefore performed anthropometric and laboratory examinations to determine the incidence of metabolic syndrome and insulin resistance in the group of 274 children with obesity (128 boys and 146 girls) aged 9-17 years. Metabolic syndrome was found in 102 subjects (37 %). On the other hand, the presence of insulin resistance according to QUICKI <0.357 was identified in 86 % and according to HOMA-IR >3.16 in 53 % of obese subjects. This HOMA-IR limit was exceeded by 70 % children in the MS(+) group, but only by 43 % children in the MS(–) group (p<0.0001). However, a relatively high incidence of insulin resistance in obese children without metabolic syndrome raises a question whether the existing diagnostic criteria do not falsely exclude some cases of metabolic syndrome. On the basis of our results we suggest to pay a preventive attention also to obese children with insulin resistance even if they do not fulfill the actual diagnostic criteria for metabolic syndrome., D. Pastucha, ... [et al.]., and Obsahuje seznam literatury
We investigated the actions of dantrolene Ca2+-induced on Ca2+-release (CICR) evoked by action potentials in cultured rat sensory neurons. The effect of dantrolene on action potential after-depolarization and voltage-activated calcium currents was studied in cultured neonatal rat dorsal root ganglion cells (DRG) using the whole-cell patch-clamp technique. Depolarizing current injection evoked action potentials and depolarizing after-potentials, which are activated as a result of CICR following a single action potential in some cells. The type of after-potentials was determined by inducing action potentials from the resting membrane potential. Extracellular application of dantrolene (10 mM) abolished after-depolarizations without affecting action potential properties. Furthermore, dantrolene significantly reduced repetitive action potentials after depolarizing current injection into these neurons, but had no significant effect on the steady-state current voltage relationship of calcium currents in these neurons. We conclude that dantrolene inhibits the induction of action potential after depolarizations by inhibiting CICR in cultured rat sensory neurons., A. Ayar, H. Kelestimur., and Obsahuje bibliografii
There are only few studies concerning about long-term effect of growth hormone (GH) replacement therapy on bone mineral density and bone microstructure. To assess effect of GH replacement therapy on bone mineral density (BMD) and trabecular bone score (TBS) in adult GH deficient (AGHD) subjects over period of 10 years. From 2005 to 2018, a prospective study of AGHD patients was conducted in national referral center for treatment of GHD. All patients received subcutaneous recombinant human GH in an IGF-1-normalizing regimen once a day. Lumbar spine (L-spine) and total hip (TH) BMD using Hologic densitometers were measured at baseline and every two years during treatment with rhGH. TBS was derived from L1-L4 DXA using iNsight® software (Medimaps, France) at each time point. Periods of measurement were baseline, year 2; 4; 6; 8 and 10. In total, 63 patients (38 males, 25 females, mean age 25.1±16 years) were included in the study. After 10 years of GH treatment, IGF-1 significantly increased (~35 %), with greatest increase at year 2. During 10-year follow-up, L-spine BMD increased approximately of 7 % (NS). TH BMD increase of 11 % during follow-up (p=0.0003). The greatest increment of BMD was achieved at year 6 on both sites, L-spine (+6 %) and TH BMD (+13 %) (p<0.05). There was no significant change of TBS during whole follow-up. In this study, sustaining positive effect of GH replacement therapy on bone density in subjects with adult GH deficiency over 10 years of follow-up was observed. The study did not show effect on TBS, as indirect measure of trabecular bone microarchitecture., Peter Vaňuga, Martin Kužma, Dáša Stojkovičová, Juraj Smaha, Peter Jackuliak, Zdenko Killinger, Juraj Payer., and Obsahuje bibliografii
The mode of inhibition of endplate currents by four esters of 1,1-dimethyl-3-oxybutyl phosphonic acid with different lipophilicities and molecule lengths were estimated by mathematical modeling based on previous electrophysiological data supplemented by several experiments with rhythmic stimulation. The aim was to discriminate between their receptor and non-receptor effects. It was shown that all esters have a two-component mechanism of depression: inhibition of the receptor open channel and allosteric modulation of the receptorchannel complex. The ratio of both functional components depends on the length and lipophilicity of the esters. Short and less lipophilic esters mostly act as open channel inhibitors and the rate of inhibition substantially depends on the rate of stimulation, i. e. probability of the receptor-channel opening. As the length of the ester radicals and their lipophilicity increased, these compounds were more active as allosteric receptor inhibitors, probably hindering the function of nAChRs from the lipid annulus., E. Pryazhnikov ... [et al.]., and Obsahuje seznam literatury
The aim of the present study was to investigate the distribution and density of noradrenergic nerve fibres (NNFs), content of catecholamines (CATs) and steroids in the cystic ovaries of gilts receiving DXM from middle luteal phase. Cystic status of ovaries was induced by i.m. DXM injections on days 7-21 of the estrous cycle. During the same time, gilts in the control group received saline. The ovaries were collected on predicted day 11 of the second studied estrous cycle. The cystic ovaries were supplied by more numerous NNFs than the control gonads. Moreover after DXM injections, the content of CATs and progesterone and androstendione (A4) in the cystic wall were elevated, while the levels of A4, testosterone and estradiol-17β in the cystic fluid were lowered. Our results show that in the porcine cystic ovaries, induced by DXM injections from middle phase of estrous cycle, increased the density of NNFs and level of CATs, and that it was accompanied by changes in the content of steroids. Moreover, this study is a further confirmation that the morphological and functional changes of cystic ovaries are partly dependent on phase of the estrous cycle in which the induction of the ovarian cysts was initiated., A. Kozłowska, ... [et al.]., and Obsahuje seznam literatury
a1_In a series of studies in the late 1950s and early 1960s, Jan Bures introduced cortical spreading depression to the field of behavioral neuroscience (eg. Bures 1960). This technique offered a unique way to study the role of cortex in learning and memory, and attracted the attention of many who began their graduate studies at that time, including one of us (LN, cf. Nadel 1966). An NIH postdoctoral fellowship to study with the master himself brought LN to Prague in September 1967. Thus began a relationship that included science, politics, and personal life, and has lasted over 30 years1,2. The first scientific exchange began with Jan pulling a piece of paper from his desk with a long list of possible experiments written on it -- “pick one”, he said. This led to a series of studies on interhemispheric transfer of learning under conditions of monocular input, demonstrating, amongst other things, that such transfer is not a uniform process. Depending on the kind of trials given with both hemispheres intact, and the eye which remained open to input, transfer can either be non-specific, likely involving some kind of procedural knowledge, or highly specific, likely involving knowledge about the trained discrimination itself (Nadel and Buresova, 1970). These studies anticipated LN’s future work on multiple memory systems, a research enterprise pursued in the following decades by many labs (including LN’s: e.g. Nadel and O’Keefe 1974, O’Keefe et al. 1975). In this paper we focus on several scientific issues that Jan has been thinking about for the past 25 years. In particular, we consider spatial learning, the hippocampus, and memory. To this mix we add stress, something well known to anyone living in Prague in 1968., a2_LN left Prague after the 1968 invasion and stayed in London for seven months, during which time arrangements were made for an eventual return to the Medical Research Council Cerebral Functions Research Group in 1970. Thus it was that LN happened to be down the hall when John O’Keefe and Jonathan Dostrovsky discovered place cells (O’Keefe and Dostrovsky 1971) and began the program of research leading to the cognitive map theory of hippocampal function (O’Keefe and Nadel 1978)., L. Nadel, J.D. Payne., and Obsahuje bibliografii
The system of IGF-I and its binding proteins may be involved in the pathogenesis of vascular damage in Type 1 diabetes. The aim of this study was to analyze the relationship between this system and the microvascular reactivity in Type 1 diabetes as measured by laser-Doppler flowmetry. Twenty-two Type 1 diabetic patients (13 women and 9 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, free IGF-I, IGFBPs and lipids were examined. The microvascular reactivity was impaired in Type 1 diabetic patients. Maximal perfusion during post-occlusive reactive hyperemia (PORHmax) and during thermal hyperemia (THmax) was significantly decreased in Type 1 diabetes (p<0.01). Percentage perfusion increase in both tests (PORH and TH) was lower in Type 1 diabetes mellitus (p<0.01) and the reaction after heating was slower in diabetic patients (THmax/t) (p<0.01). We did not find any significant dependence of microvascular reactivity on the parameters of IGF-I or its binding proteins. We conclude that the microvascular reactivity is impaired in Type 1 diabetes mellitus, but this impairment is not clearly dependent on the activity of the IGF-I system. It is probably only a complementary pathogenic factor., M. Kršek, M. Prázný, J. Škrha, V. Justová, Z. Lacinová, T. Haas., and Obsahuje bibliografii