In a frog neuromuscular preparation of m. sartorius, glutamate had a reversible dose-dependent inhibitory effect on both spontaneous miniature endplate potentials (MEPP) and nerve stimulation-evoked endplate potentials (EPP). The effect of glutamate on MEPP and EPP is caused by the activation of metabotropic glutamate receptors, as it was eliminated by MCPG, an inhibitor of group I metabotropic glutamate receptors. The depression of evoked EPP, but not MEPP frequency was removed by inhibiting the NO production in the muscle by L-NAME and by ODQ that inhibits the soluble NO-sensitive guanylyl cyclase. The glutamate-induced depression of the frequency of spontaneous MEPP is apparently not caused by the stimulation of the NO cascade. The particular glutamate-stimulated NO cascade affecting the evoked EPP can be down-regulated also by adenosine receptors, as the glutamate and adenosine actions are not additive and application of adenosine partially prevents the further decrease of quantal content by glutamate. On the other hand, there is no obvious interaction between the glutamatemediated inhibition of EPP and inhibitory pathways triggered by carbacholine and ATP. The effect of glutamate on the evoked EPP release might be due to NO-mediated modulation (phosphorylation) of the voltage-dependent Ca2+ channels at the presynaptic release zone that are necessary for evoked quantal release and open during EPP production., S. Adámek ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Endothelin-1 (ET-1) and Nerve Growth Factor (NGF) are proteins, released from cancer-ridden tissues, which cause spontaneous pain and hypersensitivity to noxious stimuli. Here we examined the electrophysiological and behavioral effects of these two agents for evidence of their interactions. Individual small-medium cultured DRG sensory neurons responded to both ET-1 (50 nM, n=6) and NGF (100 ng/ml, n=4), with increased numbers of action potentials and decreased slow K+ currents; pre-exposure to ET-1 potentiated NGF´s actions, but not vice versa. Behaviorally, single intraplantar (i.pl.) injection of low doses of ET-1 (20 pmol) or NGF (100 ng), did not increase hindpaw tactile or thermal sensitivity, but their simultaneous injections sensitized the paw to both modalities. Daily i.pl. injections of low ET-1 doses in male rats caused tactile sensitization after 21 days, and enabled further tactile and thermal sensitization from low dose NGF, in ipsilateral and contralateral hindpaws. Single injections of 100 ng NGF, without changing the paw’s tactile sensitivity by itself, acutely sensitized the ipsilateral paw to subsequent injections of low ET-1. The sensitization from repeated low ET-1 dosing and the cross-sensitization between NGF and ET-1 were both significantly greater in female than in male rats. These findings reveal a synergistic interaction between cutaneously administered low doses of NGF and ET-1, which could contribute to cancer-related pain., A. Khodorova, Y. Zhang, G. Nicol, G. Strichartz., and Seznam literatury
ntestinal inflammation induced with dextran sodium sulfate (DSS) is used to study acute or chronic ulcerative colitis in animal models. Decreased gut tissue anti-inflammatory cytokine IL-10 concentration and mRNA abundance are associated with the development of chronic bowel inflammation. Twelve piglets of 3 days old were fitted with an intragastric catheter and randomly allocated into control and DSS groups by administrating either sterile saline or 1.25 g of DSS/ kg body weight (BW) in saline per day, respectively, for 10 days. Growth rate and food conversion efficiency were reduced (p<0.05) in the DSS piglets compared with the control group. Quantitative histopathological grading of inflammation in the jejunum and colon collectively showed that the DSS tr eatment resulted in 12 fold greater (p<0.05) inflammation severity scoring in the colon than in the jejunum, indicative of chronic ulcerative colitis in the colon. Upper gut permeability endpoint was 27.4 fold high er (p<0.05) in the DSS group compared with the control group. The DSS group had higher concentrations and mRNA abundances (p<0.05) of TNF - α and IL-6 in the jejunal and colonic tissues compared with the control group. Colonic concentration and mRNA abundanc e of IL-10 were reduced (p<0.05), however, jejunal IL-10 mRNA abundance was increased (p<0.05) in the DSS group compared with the control group. In conclusion , administration of DSS at 1.25 g/kg BW for 10 days respectively induced acute inflammation in th e jejunum and chronic inflammation and ulcerative colitis in the colon with substantially decreased colonic concentration and mRNA abundance of IL-10 in the young pigs, mimicking the IL-10 expression pattern in humans associated with chronic bowel inflamma tion., D. Lackeyram, D. Young, C. J. Kim, C. Yang, T. L. Archbold, Y. Mine, M. Z. Fan., and Obsahuje bibliografii
The aim of this study was to investigate the spectral characteristics of Purkinje cell interspike background activity caused by the occurrence of particular action potentials or by electrically induced enhancement of cerebellar inhibitory and excitatory input drive. Spontaneously active Purkinje neurons were extracellularly recorded in anesthetized rats before and after cessation of stimulation from the inferior olive (IO) or locus coeruleus (LC). After A/D conversion (30 kHz), direct spectral analysis of extracted interspike background activity was done. Our results have shown that, in contrast to simple spikes, the occurrence of complex spikes induces changes in the spectra of interspike background activity. The different spectral changes of interspike background activity induced by LC and IO stimulation also indicated the importance of this extracellularly recorded phenomenon., J. Šaponjic, M. Culic, B. Jankovic, A Jovanovic., and Obsahuje bibliografii
The interval model training has been more recommended to promote aerobic adaptations due to recovery period that enables the execution of elevated intensity and as consequence, higher workload in relation to continuous training. However, the physiological and aerobic capacity adaptations in interval training with identical workload to continuous are still uncertain. The purpose was to characterize the effects of chronic and acute biomarkers adaptations and aerobic capacity in interval and continuous protocols with equivalent load. Fifty Wistar rats were divided in three groups: Continuous training (GTC), interval training (GTI) and control (CG). The running training lasted 8 weeks (wk) and was based at Anaerobic Threshold (AT) velocity. GTI showed glycogen super-compensation (mg/100 mg) 48 h after training session in relation to CG and GTC (GTI red gastrocnemius (RG)=1.41±0.16; GTI white gastrocnemius (WG)=1.78±0.20; GTI soleus (S)=0.26±0.01; GTI liver (L)=2.72±0.36; GTC RG=0.42±0.17; GTC WG=0.54±0.22; GTC S=0.100±0.01; GTC L=1.12±0.24; CG RG=0.32±0.05; CG WG=0.65±0.17; CG S=0.14±0.01; CG L=2.28±0.33). The volume performed by GTI was higher than GTC. The aerobic capacity reduced 11 % after experimental period in GTC when compared to GTI, but this change was insignificant (19.6±5.4 m/min; 17.7±2.5 m/min, effect size = 0.59). Free fatty acids and glucose concentration did not show statistical differences among the groups. Corticosterone concentration increased in acute condition for GTI and GTC. Testosterone concentration reduced 71 % in GTC immediately after the exercise in comparison to CG. The GTI allowed positive adaptations when compared to GTC in relation to: glycogen super-compensation, training volume performed and anabolic condition. However, the GTI not improved the aerobic performance., G. G. de Araujo, C. A: Gobatto, M. Marcos-Pereira, I. G. M. Dos Reis, R: Verlengia., and Obsahuje bibliografii
Nanocarriers bearing anticancer drugs are promising candidates to improve the efficacy of cancer therapy and minimize side effects. The most potent cytostatics used in the treatment of various cancers are anthracyclines, e.g. doxorubicin or pirarubicin. Recently, polymer therapeutics carrying anthracyclines have been intensively studied. The precise characterization of in vitro nanocarrier biological behavior brings a better understanding of the nanocarrier characteristics and enables prediction of the behavior of the nanocarrier during in vivo application. Advanced fluorescence detection methods, e.g. fluorescence lifetime imaging microscopy (FLIM), were successfully exploited to describe the properties of various polymeric nano-systems and contributed to a complex view of anthracyclines’ intracellular transport and DNA intercalation. Here, we report the application of a specific technique for processing FLIM images, called fluorescence pattern decomposition, to evaluate early events after doxorubicin or pirarubicin treatment of cells. Moreover, we characterized changes in the intracellular localization and release of the anthracyclines during the incubation of cells with polymer nanotherapeutics based on poly[N-(2-hydroxypropyl)- methacrylamide] (pHPMA)., J. Panek, E. Koziolova, P. Stepanek, T. Etrych, O. Janouskova., and Obsahuje bibliografii
Production of superoxide anions in the incubation medium of hippocampal slices can induce long-term potentiation (LTP). Other reactive oxygen species (ROS) such as hydrogen peroxide are able to modulate LTP and are likely to be involved in aging mechanisms. The present study explored whether intracerebro-ventricular (ICV) injection of oxidant or antioxidant molecules could affect LTP in vivo. With this aim in mind, field excitatory post-synaptic potentials (fEPSPs) elicited by stimulation of the perforant pathway were recorded in the dentate gyrus of the hippocampal formation in urethane-anesthetized rats. N-acetyl-L-cysteine, hydrogen peroxide (H2O2) or hypoxanthine/xanthine-oxidase solution (a superoxide producing system) were administrated by ICV injection. The control was represented by a group injected with saline ICV. Ten minutes after the injection, LTP was induced in the granule cells of the dentate gyrus by high frequency stimulation of the perforant pathway. Neither the H2O2 injection or the N-acetyl-L-cysteine injection caused any variation in the fEPSP at the 10-min post-injection time point, whereas the superoxide generating system caused a significant increase in the fEPSP. Moreover, at 60 min after tetanic stimulation, all treatments attenuated LTP compared with the control group. These results show that ICV administration of oxidant or antioxidant molecules can modulate LTP in vivo in the dentate gyrus. Particularly, a superoxide producing system can induce potentiation of the synaptic response. Interestingly, ICV injection of oxidants or antioxidants prevented a full expression of LTP compared to the saline injection., A. Viggiano, E. Viggiano, M. Monda, A. Viggiano, S. Ascione, S. Amaro, B. de Luca., and Obsahuje bibliografii a bibliografické odkazy
The present study was performed to evaluate the role of intrapulmonary activity of the two axes of the renin-angiotensin system (RAS): vasoconstrictor angiotensin-converting enzyme (ACE)/angiotensin II (ANG II)/ANG II type 1 receptor (AT 1 ) axis, and vasodilator ACE type 2 (ACE2)/angiotensin 1-7 (ANG 1-7)/ Mas receptor axis, in the development of hypoxic pulmonary hypertension in Ren-2 transgenic rats (TGR). Transgene-negative Hannover Sprague-Dawley (HanSD) ra ts served as controls. Both TGR and HanSD rats responded to two weeks' exposure to hypoxia with a significant increase in mean pulmonary arterial pressure (MPAP), however, the increase was much less pronounced in the former. The attenuation of hypoxic pulmonary hypertension in TGR as compared to HanSD rats was associated with inhibition of ACE gene expression and activity, inhibition of AT 1 receptor gene expression and suppression of ANG II levels in lung tissue. Simultaneously, there was an increase in lung ACE2 gene expression and activity and, in particular, ANG 1-7 concentrations and Mas receptor gene expression. We propose that a combination of su ppression of ACE/ANG II/AT 1 receptor axis and activation of ACE2/ANG 1-7/Mas receptor axis of the RAS in the lung tissue is the main mechanism explaining attenuation of hypoxic pulmonary hypertension in TGR as compared with HanSD rats., V. Hampl, J. Herget, J. Bíbová, A. Baňasová, Z. Husková, Z. Vaňourková, Š. Jíchová, P. Kujal, Z. Vernerová, J. Sadowski, L. Červenka., and Obsahuje bibliografii
Proteinuria has been recently shown to be an independent risk factor for the progression of chronic nephropathies, but the actual mechanisms by which urinary protein load damages renal tissue in humans remain unsolved. Using real-time RT-PCR method we evaluated intrarenal mRNA expression of various cytokines and chemokines in patients with biopsy-proven IgA nephropathy (IgAN, n=11), membranous nephropathy (MN, n=6) and focal and segmental glomerulosclerosis (FSGS, n=6) who exhibited proteinuria over 0.5 g/day. There was a significant positive correlation between the proteinuria extent and the intrarenal RANTES (regulated upon activation normal T cell expressed and secreted) mRNA expression in patients with IgAN, a similar trend was also observed in patients with MN and FSGS. There were no clear relationships between the proteinuria and intrarenal mRNA expression of tumor necrosis factor α, transforming growth factor β1 and monocyte chemoattractant peptide-1. There were no differences in the pattern of cytokine mRNA expression between different glomerulopathies. In conclusion, our results support the hypothesis that lymphocytes, macrophages and their products provoke tissue in jury in response to proteinuria independently of the nature of renal diseases in man., I. Brabcová, K. Kotsch, P. Hřibová, A. Loužecká, K. Bartošová, K. Hyklová, J. Lácha, H.-D. Volk, O. Viklický., and Obsahuje bibliografii a bibliografické odkazy