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621. Isoforms of troponin in normal and diseased myocardium

Creator:
Michaela Adamcová and Václav Pelouch
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Subject:
Fyziologie člověka a srovnávací fyziologie, troponiny, myokard, srdeční selhání, ontogeneze, troponins, myocardium, heart failure, ontogeny, isoforms of troponin, congenital heart disease, 14, and 612
Language:
English
Description:
M. Adamcová, V. Pelouch. and Obsahuje bibliografii
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http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

622. Jan Evangelista Purkyně and the cerebellum then and now

Creator:
František Vožeh
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Subject:
Fyziologie člověka a srovnávací fyziologie, mozeček, neurodegenerace, cerebellum, neurodegeneration, animal models, ataxia, purkinje cells, 14, and 612
Language:
English
Description:
The name of Jan Evangelista Purkyně and the cerebellum belong inseparably together. He was the first who saw and described the largest nerve cells in the brain, de facto in the cerebellum. The most distinguished researchers of the nervous system then showed him the highest recognition by naming these neurons as Purkinje cells. Through experiments by J. E. Purkyně and his followers properly functionally was attributed to the cerebellum share in precision of motor skills. Despite ongoing and fruitful research, after a relatively long time, especially in the last two decades, scientists had to constantly replenish and re-evaluate the traditional conception of the cerebellum and formulate a new one. It started in the early 1990s, when it was found that cerebellar cortex contains more neurons than the cerebral cortex. Shortly thereafter it was gradually revealed that such enormous numbers of neural cells are not without an impact on brain functions and that the cerebellum, except its traditional role in the motor skills, also participates in higher nervous activity. These new findings were obtained thanks to the introduction of modern methods of examination into the clinical praxis, and experimental procedures using animal models of cerebellar disorders described below., F. Vožeh., and Obsahuje bibliografii
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http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

623. Kainic acid lesions to the lateral tegmental field of medulla: effects on cough, expiration and aspiration reflexes in anesthetized cats

Creator:
Ján Jakuš, Stransky, A., Ivan Poliaček, Helena Baráni, and Bošeľová, Ľ.
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Subject:
Fyziologie člověka a srovnávací fyziologie, kašel, kočky, cough, cats, lateral tegmental field of the medulla, expirartion and aspiration reflexes, kainic acid lesions, midbrain transections, 14, and 612
Language:
English
Description:
We have tested the hypothesis that neurons of both the ventral reticular nucleus and the adjacent parts of the lateral tegmental field (LTF) may be important for the production of motor programs associated with cough, expiration and aspiration reflexes. Our studies were conducted on non-decerebrate, spontaneously breathing cats under pentobarbitone anesthesia. Dysfunction of the medullary LTF region above the obex, produced by uni- or bilateral injections of kainic acid (a neurotoxin), regularly abolished the cough reflex evoked by mechanical stimulation of both the tracheobronchial and laryngeal regions and in most cases also the expiration reflex induced from the glottal area. However, some electrical activity still occurred in the neurogram of the recurrent laryngeal nerve during probing the laryngeal and glottal regions. Interestingly, the aspiration reflex elicited from the nasopharynx regularly persisted, although with lower intensity after the LTF lesion. Nevertheless, successive midcollicular decerebration performed in four cats also abolished the aspiration reflex. These experiments demonstrate the importance of medullary LTF neurons for the normal occurrence of cough and expiration reflexes. One possible explanation for the elimination of these expulsive processes is that the blockade of the LTF neurons may remove an important source of a facilitatory input to the brainstem circuitries that mediate cough and expiration reflexes. In addition, the potential importance of the mesencephalic reticular formation for the occurrence of the aspiration reflex and the role of the LTF in modulating both the eupnoeic breathing and the blood pressure are also discussed., J. Jakuš, A. Stránsky, I. Poliaček, H. Baráni, Ľ. Bošeľová., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

625. Kinetics of cardiac RyR channel gating studied at high temporal resolution

Creator:
Miroslav Dura, Ivan Zahradník, and Zahradníková, A.
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Fyziologie člověka a srovnávací fyziologie, kinetika, kinetics, ryanodine receptor, gating, calcium release, cardiac muscle, 14, and 612
Language:
English
Description:
Measurements of ryanodine receptor (RyR) activity during dynamic changes of calcium concentration have suggested that RyR has at least four calcium binding sites, and that activation transpires as an increase in the activity within the high open probability H-mode. Binding of several Ca2+ ions within the H-mode should manifest itself in the steady-state RyR activity by the presence of multiple closed times. However, previously only two closed times were detected in the H-mode of RyR activity. Here we recorded steady-state activity of single cardiac RyRs with high temporal resolution and compared it to data simulated under the same conditions using our previously published model of RyR gating. At a 10 kHz resolution, the closed time histograms of both experimental and simulated data had three exponential components. The closed times of simulated data were not significantly different from those obtained experimentally. After filtering at 2 kHz, only two exponential closed time components with time constants not significantly different from those previously published could be detected in both experimental and simulated records. The conformity of the steady-state experimental data to the model derived from the dynamic data provides further support for the idea that RyRs need binding of multiple Ca2+ ions to open., M. Dura, I. Zahradník, A. Zahradníková., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

626. Kynurenic acid prevented social recognition deficits induced by MK-801 in rats

Creator:
Zdeněk Hliňák and Ivan Krejčí
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Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, amnesia, kynurenic acid, MK-801, social recognition, working memory, 14, and 612
Language:
English
Description:
MK-801 impaired social recognition potency of adult male rats when given immediately after the initial interaction with a juvenile rat. Administration of kynurenic acid prior to the initial interaction protected the adults against recognition deficits induced by MK-801. When re-exposed at a delay of 30 min to the familiar juvenile, social investigation in the adults was significantly reduced. Thus, the adults are able to remember olfactory stimuli emitted by juvenile con-specifics., Z. Hliňák, I. Krejčí., and Obsahuje bibliografii
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http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

627. L-malate enhances the gene expression of carried proteins and antioxidant enzymes in liver of aged rats

Creator:
Zeng, X., Wu, J., Wu, Q., and Zhang, J.
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Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, l-malate, mitochondria antioxidant, malate-aspartate shuttle, real-time reverse transcription polymerase chain reaction (real-time RT-PCR), 14, and 612
Language:
English
Description:
Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. To investigate the antioxidant mechanism of L-malate in the mitochondria, we analyzed the change in gene expression of two malate-aspartate shuttle (MAS)-related carried proteins (A GC, aspartate/glutamate carrier and OMC, oxoglutarate/malate carrier) in the inner mitochondrial membrane, and three antioxidant enzymes (CAT, SOD, and GSH-Px) in the mitochondria. The changes in gene expression of these proteins and enzymes were examined by real-time RT-PCR in the heart and liver of aged rats treated with L-malate. L-malate was orally administered in rats continuously for 30 days using a feeding atraumatic needle. We found that the gene expression of OMC and GSH-Px mRNA in the liver increased by 39 % and 38 %, respectively, in the 0.630 g/kg L-malate treatment group than that in the control group. The expression levels of SOD mRNA in the liver increased by 39 %, 56 %, and 78 % in the 0.105, 0.210, and 0.630 g/kg L-malate treatment groups, respectively. No diffe rence were observed in the expression levels of AGC, OMC, CAT, SOD, and GSH-Px mRNAs in the heart of rats between the L-malate treatment and control groups. These results predicted that L-malate may increase the antioxidant capacity of mitochondr ia by enhancing the expression of mRNAs involved in the MAS and the antioxidant enzymes., X: Zeng, J. Wu, Q. Wu, J. Zhang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

628. Lactate dehydrogenase activity in human placenta following exposure to environmental pollutants

Creator:
Kaiglová, A., Eva Reichrtová, Adamčáková, A., and Wsólová, L.
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Fyziologie člověka a srovnávací fyziologie, placenta, human placenta, lactate dehydrogenase, environmental pollutants, 14, and 612
Language:
English
Description:
The impact of environmental pollution at the place of residence of pregnant women and of their smoking habits on the cellular energy metabolism of placental tissue was investigated. Samples of full-term placentas were randomly collected from two environmentally different regions of Slovakia (Bratislava, Stará Ľubovňa) and the activity of lactate dehydrogenase (LDH) was measured. Our results showed enhanced LDH activity in the placenta that was dependent on both the type of environmental pollutants at the place of residence and the smoking habits during pregnancy. The enhanced LDH activity may reflect hypoxic conditions due to the accumulation of heavy metals and toxic compounds of tobacco smoke in the placental tissue. A high content of heavy metal particles, found in placental samples from Stará Ľubovňa in our previous studies, might contribute to the increased LDH activity in placentas from this region. We hypothesize that fine metal particles deposited in the placental tissue might be phagocytozed by the syncytiotrophoblast, thus contributing to the decreased oxygen level in placental tissue., A. Kaiglová, E. Reichrtová, A. Adamčáková, L. Wsólová., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

629. Late blood pressure reduction in SHR subjected to transient captopril treatment in youth: possible mechanisms

Creator:
Josef Zicha, Zdena Dobešová, and Jiří Kuneš
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, genetika živočichů, hypertenze, physiology, animal genetics, hypertension, genetic hypertension, late effects of early treatment, captopril, nifedipine, 14, and 612
Language:
English
Description:
Spontaneously hypertensive rats (SHR) are characterized by enhanced nifedipine-sensitive component of sympathetic vasoconstriction. Our study tried to elucidate the mechanisms responsible for long-term reduction of blood pressure (BP) in SHR subjected to early transient captopril treatment. Adult untreated SHR aged 30-34 weeks were compared with animals subjected to chronic captopril treatment for 6 weeks either in youth (between 4 and 10 weeks of age) or in adulthood (between 24 and 30 weeks of age). Antihypertensive effects of captopril were more pronounced in young than adult SHR. This was due to greater attenuation of sympathetic and nifedipine-sensitive BP components and prevention of residual BP rise in young captopril-treated SHR in which the reductions of nifedipine-sensitive BP component and residual BP persisted for 20 weeks after captopril withdrawal. The magnitude of nifedipine-sensitive component of sympathetic vasoconstriction is decisive for BP maintenance not only in untreated SHR but also in SHR during active captopril treatment by or after its withdrawal., J. Zicha, Z. Dobešová,J. Kuneš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

630. Leptin inhibits gastric emptying in rats: role of CCK receptors and vagal afferent fibers

Creator:
Çakir, B., Kasimay, Ö, Devseren, E., and Yeğen, Berrak Ç.
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Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, leptin, žaludek, physiology, stomach, capsaicin-sensitive vagal fibers, CCK (cholecystokinin), adrenergic, gastric emptying, 14, and 612
Language:
English
Description:
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
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http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public