The aim of our in vitro studies was to understand the role of leptin in controlling proliferation, apoptosis, and protein kinase A (PKA) in human ovarian cells. We analyzed the in vitro effects of leptin (0, 1, 10 or 100 ng/ml) on the accumulation of proliferation-related peptides (PCNA, cyclin B1), apoptosis-associated peptide (Bax) and the intracellular signaling molecule PKA in cultured human granulosa cells using immunocytochemistry and Western immunoblotting. It was observed that leptin stimulated in a dose-dependent manner the accumulation of PCNA (at doses 1-100 ng/ml), cyclin B1 (at doses 10 or 100 ng/ml), Bax (at doses 10 or 100 ng/ml) and PKA (at doses 1-100 ng/ml) in cultured human ovarian cells. These observations suggest the ability of leptin to control directly human ovarian cell functions: proliferation, apoptosis, and intracellular messenger PKA., A. V. Sirotkin, M. Mlynček, A. V. Makarevich, I. Florkovičová, L. Hetényi., and Obsahuje bibliografii a bibliografické odkazy
a1_Leptin regulates energy homeostasis and body weight by balancing energy intake and expenditure. It was recently reported that leptin, released into the gut lumen during the cephalic phase of gastric secretion, is capable of initiating intestinal nutrient absorption. Vagal afferent neurons also express receptors for both CCK and leptin, which are believed to interact in controlling food intake. The present study was undertaken to investigate the central and peripheral effects of leptin on gastric emptying rate. Under anesthesia, male Sprague-Dawley rats (250-300 g) were fitted with gastric Gregory cannulas (n=12) and some had additional cerebroventricular cannulas inserted into their right lateral ventricles. Following recovery, the rate of gastric emptying of saline (300 mOsm/kg H2O) was determined after instillation into the gastric fistula (3 ml, 37°C, containing phenol red, 60 mg/l as a non-absorbable dilution marker). Gastric emptying rate was determined from the volume and phenol red concentrations recovered after 5 min. Leptin, injected intraperitoneally (ip; 10, 30, 60, 100 μg/kg) or intracerebroventricularly (icv; 5, 15 μg/rat) 15 min before the emptying, delayed gastric emptying rate of saline at the dose of 30 μg/kg or 15 μg/rat (p<0.001). When CCK 1 receptor blocker L-364,718 (1 mg/kg, ip), CCK 2 receptor blocker L-365,260 (1 mg/kg, ip) or adrenergic ganglion blocker bretylium tosylate (15mg/kg, ip) was administered 15 min before ip leptin (30 μg/kg) injections, leptin-induced delay in gastric emptying was abolished only by the CCK 1 receptor blocker (p<0.001)., a2_However, the inhibitory effect of central leptin on gastric emptying was reversed by adrenergic blockade, but not by either CCK antagonists. Our results demonstrated that leptin delays gastric emptying. The peripheral effect of leptin on gastric motility appears to be mediated by CCK 1 receptors, suggesting the release of CCK and the involvement of vagal afferent fibers. On the other hand, the central effect of leptin on gastric emptying is likely to be mediated by adrenergic neurons. These results indicate the existence of a functional interaction between leptin and CCK receptors leading to inhibition of gastric emptying and short-term suppression of food intake, providing an additional feedback control in producing satiety., B. Çakir, Ö. Kasimay, E. Devseren, B. Ç. Yeğen., and Obsahuje bibliografii a bibliografické odkazy
In rats, the basic licking rhythm is generated by the central pattern generator located in the brainstem. Nevertheless, the licking frequency can be regulated between abou 7.5 and 4 Hz by changing the drinking conditions. If these conditions are kept constant, the licking frequency can be influenced only to a minor degree by factors such as deprivation level, type of solution, and phase of the session. The aim of our study was to compare the licking frequency of rats at different levels of vigilance. We investigated spontaneous licking of rats by an electrical lick sensor; parallel behavior monitoring was also performed. Animals kept in a stable environment and showing a lower level of vigilance licked at a rate of 5.96 Hz, fully vigilant rats licked significantly more rapidly at a frequency 6.57 Hz. The fastest rate of licking (6.49 Hz and 6.82 Hz, respectively) was encountered in alert rats under a mild stress caused by the presence of a second animal in the experimental box. The vigilance level is thus another factor affecting the licking rate of rats that should be taken into account in behavioral licking experiments., O. Vajnerová, E. Bielavská, P. Jiruška, G. Brožek., and Obsahuje bibliografii
The apolipoprotein A-V (apo A-V) plays an important role in regulation of triglyceride (TG) concentration in serum. To better understand how apo A-V affects triglyceridemia and glucoregulation, the lipoprotein lipase (LPL) activity was determined using intravenous fat tolerance test (IVFTT) and oral glucose tolerance test (oGTT) was performed in carriers of apolipoprotein A-V gene ( APOAV) variants known to be associated with increased triglyceridemia. Twelve carriers of 19W variant, 16 carriers of -1131C variant, 1 combined heterozygote and 16 control subjects homozygous for wild type variants (19S/-1131T) were selected from a population sample and matched with respect to body mass index and age. The APOAV variants carriers had increased TG, very low density lipoprotein-TG, and apo B concentrations (p < 0.05). The LPL activity evaluated as k2 rate constant for clearance of Intralipid® was 14 % lower in APOAV variants carriers. The depression of nonesterified fatty acids (NEFA) concentration after glucose load was delayed in APOAV variants carriers in spite of the same insulinemia and glycemia. Our results suggest that variants of APOAV combined with increased triglyceridemia are associated with lower LPL activity in vivo and with disturbances of regulation of NEFA concentration after glucose load., J. Kovář, V. Adámková., and Obsahuje bibliografii a bibliografické odkazy
Lipoprotein(a) [Lp(a)] comprises of an LDL particle and apolipoprotein(a) [apo(a)] and its elevated levels are considered a risk factor for atherosclerosis. The aim of our study was to find out whether elevated Lp(a) levels are associated with increased risk of atherosclerosis in patients with multiple other risk factors. We further tested the association of three polymorphisms of the apo(a) gene promoter with Lp(a) levels. No significant correlation was detected between Lp(a) levels and lipid and clinical parameters tested. The study demonstrated a significantly (p=0.0219) elevated Lp(a) level (mean 28±35 mg/dl, median 0.14) in patients with coronary heart disease (CHD). In a group with premature CHD the correlation was not significant anymore. There was a significant correlation between polymorphic loci of the promoter region of apo(a) gene and Lp(a) levels (+93C>T, p=0.0166, STR, p<0.0001). Our study suggests that elevated Lp(a) level is an independent risk factor of CHD in carriers of other important CHD risk factors. Observed association of sequence variants of the promoter of apo(a) gene with Lp(a) levels is caused in part due to linkage to a restricted range of apo(a) gene length isoforms., L. Zlatohlávek, K, Zídková, M. Vrablík, T. Haas, M. Prusíková, H. Svobodová, R. Češka., and Obsahuje bibliografii a bibliografické odkazy
Alterations in geometry and structure of coronary arteries have marked consequences on blood flow to the respective area. We evaluated long-term effect of losartan on blood pressure (BP), heart weight/body weight (HW/BW), geometry and structure of septal branch of coronary artery (RS) of young SHR and Wistar rats. Four-week-old Wistar rats and SHR were used. Losartan was administered (20 mg/kg/day) in drinking water by gavage for 5 weeks. BP was measured by plethysmographic method. Cardiovascular system was perfused with a fixative (120 mm Hg). RS was processed for electron microscopy. Wall thickness of intima + media (WT), inner diameter (ID), cross-sectional area of intima + media (CSA), volume dens ities (VD) of endothelial cells (EC), extracellular matrix (ECM) of intima, smooth muscle cells (SMC) and ECM of media were eval uated. BP of 4-week-old SHR did not differ from that of Wistar rats. BP, HW/BW, WT, CSA, WT/ID, CSAs of SMC, ECM of media were increased in 9-week- old SHR, whereas their VD and CSA of EC were decreased. Losartan administration decreased BP and HW/BW in both groups. Geometry of RS was affected only in SHR (reduction of WT, CSA, WT/ID and increased of ID, circumferential tension, VD and CSA of EC). Losartan administration reduced BP and myocardial mass in both groups and beneficially affected geometry and structure of coronary artery in SHR., R. Koprdová, M. Cebová, F. Kristek., and Obsahuje seznam literatury
We studied the effects of long-term administration of molsidomine and pentaerythrityl tetranitrate (PETN) on the cardiovascular system of spontaneously hypertensive rats (SHR). One control and three experimental groups of 10-week-old animals were used: 1) control Wistar rats, 2) SHR, 3) SHR treated with molsidomine in tap water (100 mg/kg/day, by gavage), and 4) SHR treated with PETN in tap water (200 mg/kg/day, by gavage). After six weeks, the content of cGMP in platelets and NO synthase (NOS) activity in aortas were evaluated in the experimental groups. For morphological evaluation the rats were perfused at 120 mm Hg with a glutaraldehyde fixative and the arteries were processed for electron microscopy. Blood pressure and heart weight/body weight ratio (HW/BW) were increased in all experimental groups with respect to the controls. HW/BW was lower in the molsidomine group in comparison to both SHR and PETN-treated group. The platelet content of cGMP was increased and the activity of NOS in the aortas was decreased in the molsidomine and PETN-treated groups. Wall thickness and cross-sectional area of thoracic aorta, carotid artery and coronary artery were increased similarly in all experimental groups compared to the controls, but there were no differences among the experimental groups. We summarize that long-term administration of exogenous NO donors did not improve pathological changes of the cardiovascular system in SHR., F. Kristek, V. Fáberová, I. Varga., and Obsahuje bibliografii
Polyunsaturated omega-3 fatty acids ( ω-3 PUFA) are important components of cell membrane a ffecting its function and their deficiency is deleterious to health. We have previously shown that spontaneously hypertensive rats (SHR) are prone to life- threatening arrhythmias that are reduced by ω-3 PUFA intake. Purpose of this study was to explore plasma and red blood cells (RBC) profile of ω-3 and ω-6 PUFA as well as to determine ω-3 index, a risk factor for sudden cardiac death, in aged SHR and the effect of ω-3 PUFA intake. Male and female 12-month-old SHR and age-matched Wi star rats fed with ω-3 PUFA (200 mg/kg BW/day/2 month) were compared with untreated rats. Composition of ω-3 PUFA: alfa linolenic acid, eicosapentaenoic acid (EPA) and docosahexaen oic acid (DHA) as well as ω-6 PUFA: linoleic acid and arachidonic acid was analyzed by gas chromatography. Results showed sex- and strain-related differences of basal ω-3 and ω-6 PUFA levels in plasma and RBC as well as in response to ω-3 PUFA intake. Comparing to Wistar rats ω-3 index, expressed as a percentage of EPA+DHA of total fatty acids, was lower in SHR and it increased due to consumption of ω-3 PUFA. Findings support our hypothesis that lower ω-3 index may be also a marker of increased propensity of the hypertensive rat heart to malignant arrhythmias., B. Bačová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Arterial sites with low wall shear stress (WSS) are more prone to the development of atherosclerotic plaques, as was observed in carotid arteries in subjects with atherosclerosis risk factors. Type 2 diabetes mellitus (DM), hypertension, hyperlipidemia and other components of the metabolic syndrome, are associated with high risk for symptomatic cerebrovascular disease. It was shown by others that untreated type 2 DM is associated with lower WSS in common carotid arteries. However, the cardiovascular risk of type 2 DM could be modified by therapy. The aim of our study was to test the hypothesis that treated type 2 DM subjects with metabolic syndrome still have lower WSS in common carotid arteries than healthy controls. We enrolled 26 compensated DM subjects with metabolic syndrome, treated by metformin, statins and ACEI for more than 6 months, and 22 aged-comparable healthy controls. Wall shear rate (WSR) was used as a measure of WSS. A linear 3-11 MHz probe was used to measure blood velocity and internal diameter in the common carotid arteries. We compared observed values of WSR adjusted for age by ANCOVA. Wall shear rate was significantly lower in DM group than in control subjects: peak (systolic) values of wall shear rate were 410±130 s-1 vs. 487±111 s-1 (p<0.005). DM subjects had significantly lower WSR, because of both thinner lumen and slower blood flow velocities. Lower WSR was accompanied by higher IMT (0.73±0.12 mm vs. 0.64±0.11 mm, p<0.001). Treated subjects with compensated type 2 DM with metabolic syndrome still have atherogenic hemodynamic profile. These findings might help to understand faster progression of atherosclerosis in diabetic subjects with metabolic syndrome despite up-to-date medication., E. Chytilová ...[et al.]., and Obsahuje seznam literatury
The aim of this work is to present the efficacy of a previously introduced computational procedure, developed for evaluation of vascular responsiveness. On this reason, as an example a common study of noradrenaline (NA) effect on a rat renal artery under in vitro conditions was arbitrarily selected. The response of the arterial segment to NA doses (0.1-10 μg) was digitally recorded on a PC and employed to develop mathematical model of NA effect. Using the model, the following NA effect variables were determined: the vessel sensitivity parameter, mean effect time and rate constant, respectively, characterizing the effect intensity, duration, and regression and also classic response variables: the maximal effect and time of the maximal effect. The two-way analysis of variance followed by Bonferroni’s test revealed a significant influence of the increasing NA dose on the vessel sensitivity parameter and mean effect time. These findings indicated nonlinearity of processes underlying NA effect on the rat renal artery over the given range of NA doses. The procedure exemplified has the potential for use as an effective adjunct to routine studies of vascular responsiveness as it enables the extraction of meaningful information which cannot by obtained by common manual evaluation procedures., M. Ďurišová, L. Dedík, V. Kristová, R. Vojtko., and Obsahuje bibliografii a bibliografické odkazy