Pregnant rats were exposed to intermittent hypobaric hypoxia (at a simulated altitude of 7000 m or 5000 m) and the excitability of cortical neurons of their pups was tested. Stimulation of the sensorimotor cortex of rats prenatally exposed to hypoxia shortened the duration of cortical afterdischarges in 12-day-old rats, but did not change the excitability in 25-day-old animals. Shortening of the first afterdischarge in 35-day-old rats but the prolongation of the first afterdischarge in adult rats (as compared to the duration of cortical afterdischarges in rats not exposed to prenatal hypoxia) were registered. The possible mechanisms of different excitability of cortical neurons in rats prenatally exposed to hypobaric hypoxia are discussed., D. Marešová, I. Valkounová, K. Jandová, J. Bortelová, S. Trojan., and Obsahuje bibliografii
Vascular smooth muscle cells (VSMC) display considerable phenotype plasticity which can be studied in vivo on vascular remodeling which occurs during acute or chronic vascular injury. In differentiated cells, which represent contractile phenotype, there are characteristic rapid transient changes of intracellular Ca2+ concentration ([Ca2+]i), while the resting cytosolic [Ca2+]i concentration is low. It is mainly caused by two components of the Ca2+ signaling pathways: Ca2+ entry via L-type voltagedependent Ca2+ channels and dynamic involvement of intracellular stores. Proliferative VSMC phenotype is characterized by long-lasting [Ca2+]i oscillations accompanied by sustained elevation of basal [Ca2+]i. During the switch from contractile to proliferative phenotype there is a general transition from voltagedependent Ca2+ entry to voltage-independent Ca2+ entry into the cell. These changes are due to the altered gene expression which is dependent on specific transcription factors activated by various stimuli. It is an open question whether abnormal VSMC phenotype reported in rats with genetic hypertension (such as spontaneously hypertensive rats) might be partially caused by a shift from contractile to proliferative VSMC phenotype., E. Misárková, M. Behuliak, M. Bencze, J. Zicha., and Obsahuje bibliografii
The effects of Lathyrus sativus neurotoxin were studied on the cell membrane potential and cellular cation composition in Retzius nerve cells of the leech Haemopis sanguisuga, with ion-selective microelectrodes using liquid ion-exchangers. Bath application of 10-4 mol/l Lathyrus sativus neurotoxin for 3 min depolarized the cell membrane potential and decreased the input resistance of directly polarized membrane in Retzius neurons. At the same time the cellular Na+ activity increased and cellular K+ activity decreased with slow but complete recovery, while the intracellular Ca2+ concentration was not changed. Na+-free Ringer solutions inhibited the depolarizing effect of the neurotoxin on the cell membrane potential. Zero-Ca2+ Ringer solution or Ni2+-Ringer solution had no influence on the depolarizing effect of the neurotoxin on the cell membrane potential. It is obvious that the increase in membrane conductance and depolarization of the cell membrane potential are due to an influx of Na+ into the cell accompanied by an efflux of K+ from the cell., D. Cemerikić, V. Nedeljkov, S. Lopičić, S. Dragović, B. Beleslin., and Obsahuje bibliografii
Converted from MARCXML to MODS version 3.5 using MARC21slim2MODS3-5.xsl (Revision 1.106 2014/12/19)(EE patch 2015/05/15), Knihopis neuvádí., Titulní list v ozdobném rámu, taktéž samotný text, iniciály, kustody, signatury, vlysy, viněty, ozdůbky, notace, bez záhlaví a číslování., and Converted from MODS 3.5 to DC version 1.8 (EE patch 2015/06/25)
It is known that excessive sympathetic activity and oxidative stress are enhanced in obesity. This study aimed to clarify whether exercise training (ET) attenuates sympathetic activation and oxidative stress in obesity. The obesity was induced by highfat diet (HFD) for 12 weeks. Male Sprague-Dawley rats were assigned to four groups: regular diet (RD) plus sedentary (RD-S), RD plus ET (RD-ET), HFD plus sedentary (HFD-S), and HFD plus ET (HFD-ET). The rats in RD-ET and HFD-ET groups were trained on a motorized treadmill for 60 min/day, five days/week for 8 weeks. The sympathetic activity was evaluated by the plasma norepinephrine (NE) level. The superoxide anion, malondialdehyde and F2-isoprostanes levels in serum and muscles were measured to evaluate oxidative stress. The ET prevented the increases in the body weight, arterial pressure and white adipose tissue mass in HFD rats. The NE level in plasma and oxidative stress related parameters got lower in HFD-ET group compared with HFD-S group. We have found decreased mRNA and protein levels of toll-like receptor (TLR)-2 and TLR-4 by ET in HFD rats. These findings suggest that ET may be effective for attenuating sympathetic activation and oxidative stress in diet-induced obesity., G. Li, J.-Y. Liu, H.-X. Zhang, Q. Li, S.-W. Zhang., and Obsahuje bibliografii
This study investigated the effect of exercise training on the flow- mediated dilation (FMD) in gastrocnemius muscle arteries from spontaneously hypertensive rats (SHR). SHR and WKY rats were divided into sedentary and exercised groups. After swimming exercise for eight weeks, the isolated arteries were mounted on pressurized myograph and FMD re sponses examined. The role of nitric oxide (NO), prostaglandins (PGs) and endothelium derived hyperpolarizing factor (EDHF) on FMD were assessed by obtaining dilation responses in the presence and absence of pharmacological antagonists. Nω-nitro-L-arginine methyl ester (L-NAME), indomethacin (INDO) and tetraethylamonium (TEA) were used to inhibit nitric oxide synthase, cyclooxygenase and EDHF-mediated responses, respectively. The FMD response was significantly blunted in arteries of SHR compared with WKY rats, and, improved by exercise training in SHR (SHR-ET) group. In SHR arteries, L-NAME and TEA did not affect dilation responses to flow, while INDO led to a significant enhancement in this response. Although dilation response was not altered by L-NAME in arteries obtained from trained SHR, TEA caused a significant attenuation and INDO led to significant increases. These results demonstrate that exercise training improves FMD in SHR, and, this enhancement induced by exercise training occurs through EDHF-mediated mechanism(s)., F. Gündüz ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy