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General Physiology and Biophysics

Volume 31, 2012, No. 2


  IP3 receptors, stress and apoptosis
Lubomira Lencesova 1), Olga Krizanova

1)Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovak Republic.

Inositol 1,4,5-trisphosphate (IP3) receptors are intracellular calcium channels that are able to release calcium from intracellular stores upon activation by IP3 and modulation by calcium. IP3 receptors are involved in variety of processes during physiological, but also in the pathophysiological states. Unraveling their regulation and function, especially under the pathological situations can result in a development of new therapeutic strategies based on the IP3 receptor´s activation and/or blocking. To the stimuli that can modulate IP3 receptors belong several stress factors (e.g. immobilization stress, oxidative stress and hypoxia) and also apoptosis. Depending on the length and strength of the stress stimulus, expression of IP3 receptors can be increased, or decreased. Therefore, in this minireview modulation of IP3 receptors by some stressors is discussed. Since it was already shown that strong hypoxia might lead to the apoptosis induction, special focus will be given to the hypoxic stress and induction of apoptosis.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 119-130.

  Advances in patch clamp technique: towards higher quality and quantity
Markéta Bébarová 1)

1)Department of Physiology, Faculty of Medicine, Masaryk University, 625 00 Brno-Bohunice, Czech Republic.

The patch clamp technique, developed in late 1970s, started a new period of experimental cardiac electrophysiology enabling measurement of ionic currents on isolated cardiomyocytes down to the level of single channels. Since that time, the technique has been substantially improved by development of several upgraded modifications providing so far unavailable data (e.g. action potential clamp, dynamic clamp, high-resolution scanning patch clamp), or facilitating the patch clamp technique by increasing its efficiency (planar patch clamp, automated patch clamp). The current review summarizes the leading new patch clamp based techniques used in cardiac cellular electrophysiology, their principles and prominent related papers.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 131-140.

  Morphological and functional characteristics of models of experimental myocardial injury induced by isoproterenol
Zuzana Nichtova 1), Marta Novotova, Eva Kralova, Tatiana Stankovicova

1)Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovak Republic.

The animal models of myocardial injury induced by systemic β-adrenergic receptor agonist administration represent an experimental approach of persisting interest. These models were found useful especially for studies of structural and functional adaptation of myocardium during the progression of cardiac adaptive response towards maladaptive hypertrophy and insufficiency. The pathological alterations induced by isoproterenol (ISO) do not develop evenly. The ISO models may contribute effectively to understanding of pathologies in signal transduction, energetics, excitability and contractility that may contribute concomitantly to cardiac dysfunction and heart failure. In this minireview we focused on the alterations in general characteristics and heart function as well as on the morphological changes of cardiomyocytes developed during ISO administration. The morphological alterations within the cellular macro- and microdomains correspond to the electrical remodelling and contractile dysfunction of ventricular myocardium that could be used to identify pathological changes ranging from hypertrophy to failing heart.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 141-151.

  Age-dependent changes in ion channel mRNA expression in canine cardiac tissues
Mónika Gönczi 1), Péter Birinyi, Bernadett Balázs, Norbert Szentandrássy, Gábor Harmati, Zoltán Könczei, Laszlo Csernoch, Péter Nánási

1)Department of Physiology, University of Debrecen, Debrecen, Hungary.

The expression pattern of cardiac ion channels displays marked changes during ontogeny. This study was designed to follow the developmental changes in the expression of major ventricular and atrial ion channel proteins (including both pore forming and regulatory subunits) in canine cardiac tissues at the mRNA level using competitive reverse transcription polymerase chain reaction. Therefore, the corresponding mRNA levels were compared in myocardial tissues excised from embryonic (25–60 days of gestation) and adult (2–3 years old) canine hearts. Expression level of Kv4.3, Kv1.4, KChIP2, KvLQT1, and Cav3.2 mRNAs were higher in the adult than in the embryonic hearts, while expression of Nav1.5 and minK mRNAs were higher in the embryonic than in the adult myocardium. No change in Kir2.1, HERG, Kv1.5, and Cav1.2 mRNA was observed during ontogeny. Direction of the developmental change in the mRNA level, determined for any specific channel protein, was identical in the atrial and ventricular samples. The age-dependent increase observed in the expression of Kv4.3, Kv1.4, KChIP2, and KvLQT1 is congruent with the greater repolarization reserve of the adult myocardium, associated with higher densities of Ito and IKs. The results indicate that age-dependent changes in the expression pattern of many ion channels are similar in canine and healthy human myocardium, therefore, canine cardiac muscle can be considered as a good model of studying developmental changes in the human heart.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 153-162.

  Cortico-pontine theta carrier frequency phase shift across sleep/wake states following monoaminergic lesion in rat
Aleksandar Kalauzi 1), Sladjana Spasic, Jelena Petrovic, Jelena Ciric, Jelena Saponjic

1)University of Belgrade, Department of Life Sciences, Institute for Multidisciplinary Research, 11030, Belgrade, Serbia.

This study was aimed to explore the sleep/wake states related cortico-pontine theta carrier frequency phase shift following a systemically induced chemical axotomy of the monoaminergic afferents within a brain of the freely moving rats. Our experiments were performed in 14 adult, male Sprague Dawley rats, chronically implanted for sleep recording. We recorded sleep during baseline condition, following sham injection (saline i.p. 1 ml/kg), and every week for 5 weeks following injection of the systemic neurotoxins (DSP-4 or PCA; 1 ml/kg, i.p.) for chemical axotomy of the locus coeruleus (LC) and dorsal raphe (DR) axon terminals. After sleep/wake states identification, FFT analysis was performed on 5 s epochs. Theta carrier frequency phase shift (∆Φ) was calculated for each epoch by averaging theta Fourier component phase shifts, and the ∆Φ values were plotted for each rat in control condition and 28 days following the monoaminergic lesions, as a time for permanently established DR or LC chemical axotomy. Calculated group averages have shown that ∆Φ increased between pons and cortex significantly in all sleep/wake states (Wake, NREM and REM) following the monoaminergic lesions, with respect to controls. Monoaminergic lesions established the pontine leading role in the brain theta oscillations during all sleep/wake states.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 163-171.

  Impact of chronic ethanol intake of rat mothers on the seizure susceptibility of their immature male offspring
Vladimir Riljak 1), Dana Maresova, Katerina Jandova, Jana Bortelova, Jaroslav Pokorny

1)Institute of Physiology, First Faculty of Medicine, Charles University in Prague, Czech Republic.

The aim of present study was to examine the impact of prenatal ethanol exposure on seizure susceptibility of the offspring. Pregnant Wistar rats were compelled to drink either 10% or 20% ethanol solution, as the only drinking fluid since conception up to the weaning of their offspring at the age of 28 days. Pregnant and nursing rats of the control group drank water. Electrophysiological experiments (repeated electrical stimulation and analysis of cortical afterdischarges duration) were than performed on their immature offspring. Rat pups were tested on postnatal day 18, 25, and 35. Shortening of afterdischarges duration was observed in 18-day-old animals (mothers drank 20% ethanol) when compared with age matched controls and failure of post-ictal depression phenomenon was found in 25- and 35-day-old animals. Our findings signalize that ethanol exposure during pregnancy influences seizure susceptibility by acting on excitatory/inhibitory brain systems and this effect is dose- and age-dependent.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 173-177.

  Effect of normobaric oxygen treatment on oxidative stress and enzyme activities in guinea pig heart
Zuzana Tatarkova 1), Ivan Engler, Andrea Calkovska, Daniela Mokrá, Anna Drgova, Stanislav Kuka, Peter Racay, Ján Lehotský, Dušan Dobrota, Peter Kaplan

1)Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.

Normobaric oxygen (NBO) therapy is commonly applied for the treatment of various diseases, including myocardial infarctions, but its effectiveness is controversial. Potential adverse effects of hyperoxia are related to excessive formation of free radicals. In the present study we examined the effect of 60-h NBO treatment on lipid peroxidation (LPO), activity of manganese superoxide dismutase (Mn-SOD) and mitochondrial enzymes of energy metabolism in guinea pig heart. NBO treatment resulted in significant accumulation of thiobarbituric acid reactive substances and loss of Mn-SOD activity despite slight elevation of Mn-SOD protein content. Activity of electron transport chain complex III decreased significantly, while activity of complex IV was slightly elevated and citrate synthase was unchanged. LPO, inhibition of Mn-SOD and complex III activities were more pronounced when inhaled oxygen was partially enriched with superoxide radical. In contrast, when O2 was enriched with oxygen cation (O2●+), LPO and loss of Mn-SOD activity were prevented. Complex III activity in the O2●+-treated group remained depressed but activities of complex IV and citrate synthase were elevated. These data suggest that NBO treatment is associated with myocardial oxidative damage and attenuation of antioxidant defense, but these adverse effects can be partially attenuated by inhalation of O2 enriched with oxygen cation.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 179-184.

  Influence of age on pain sensitivity in response to paw pressure and formalin injection in rats: A role of nitric oxide
Nisreen Omar 1), Abdelaziz Hussein, Hala Malek, Mohamed Ahdy Saad, Dalia Saleh

1)Department of Physiology and Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.

The effect of age on pain response to paw pressure and intraplantar formalin injection in rats is elucidated. Pain responses evoked by mechanical pressure on hind paw and intraplantar injection of formaldehyde (5%) into the hind paw were evaluated in groups of adult, young and aged male Sprague Dawley rats, after intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) injection of L-arginine or NG-nitro-L-arginine methyl ester (L-NAME). Nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining was done in the two groups. The results show that pain response was reduced in the aged rats and enhanced pain response to paw pressure in aged rats only. L-arginine (i.c.v.) had no effect on pain response to paw pressure in the two groups but enhanced biphasic pain response to formalin. L-NAME (i.p. and i.c.v.) suppressed pain response to paw pressure in the two groups. L-NAME (i.c.v.) suppressed pain response to formalin during the acute phase and enhanced it during the late phase. NADPH-diaphorase activity was significantly greater in young rats. In conclusion, pain response is blunted in the aged rats. NO might be involved in mechanical nociception in aged rats and in formalin-induced nociception in both groups. NO blockade has an antinociceptive effect on pain response. Central NO has dual role in pain response evoked by formalin.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 185-194.

  Alteration of renal functional, oxidative stress and inflammatory indices following hepatic ischemia-reperfusion
Mehri Kadkhodaee 1), Saideh Mikaeili, Maryam Zahmatkesh, Freshteh Golab, Behjat Seifi, Hossein-Ali Arab, Sedigheh Shams, Mitra Mahdavi-Mazdeh

1)Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

Liver ischemia/reperfusion (IR) injury is a complex phenomenon that may cause local as well as remote organ injuries. Reactive oxygen species (ROS) along with many pro- and anti- inflammatory cytokines are implicated in the development of organ injury. The renal functional, histological, oxidative stress and inflammatory indices were studied during a short and a longer period of liver IR. Rats were subjected to either sham operation or 90 min partial liver ischemia followed by 4 or 24 h of reperfusion. Serum ALT, AST, ALK and LDH levels, BUN and creatinine, renal MDA level, SOD and catalase activities were evaluated as well as serum IL-6 and IL-10 concentrations along with renal histological evaluation. Ninety minutes liver ischemia /4 h reperfusion caused an increase in BUN and renal MDA levels and a decrease in SOD and catalase activities. It also caused an increase in serum IL-6 and IL-10 levels. 24 h liver reperfusion resulted in a reduction in BUN levels and lower oxidative damages demonstrated by a decrease in renal MDA levels and an increase in renal SOD and catalase activities comparing to 4 h reperfusion group. Evaluations indicated improvement in histology such as less cytoplasmic vacuolation and lower tubular debris. Serum inflammatory indices (IL-6 and IL-10 levels) were also reduced. This study showed that liver IR damage causes renal injury including functional, inflammatory and oxidative status changes. The remote kidney damage was then improved by continuing reperfusion from 4 to 24 h.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 195-202.

  Histomorphometric features of ventral prostate in different aged rats after central ghrelin treatment
Bosiljka Plecas-Solarovic 1), Dejan Nesic, Darko Stevanovic, Aleksandar Obradovic, Marina Djelic, Verica Milosevic, Vesna Starcevic

1)Institute of Physiology, Faculty of Pharmacy, University of Belgrade, 11000 Belgrade, Serbia.bosiljka.

Ghrelin, the endogenous ligand of growth hormone secretagogue receptor type 1a (GHS-R1a), has emerged as pleiotropic modulator of diverse biological functions, including energy homeostasis and recently, reproduction. The influence of intracerebroventricularly (ICV) administered ghrelin (1 μg/day/rat for 5 days) to rats of different ages, i.e, peripubertal (38 days), adult (60 days) and middle-aged (180 days) on the ventral prostate size and morphology, serum testosterone levels and testis weight was examined. Ghrelin treatment significantly increased (p < 0.05) absolute ventral prostate weight in peripubertal and middle-aged rats, by 27% and 37% respectively, due to enhancement of epithelial and/or luminal compartment of the gland. In adult rats, both absolute and relative volumes of the acinar lumen were significantly decreased (p < 0.05), by 38% and 44% respectively, which was associated with significant increases (p < 0.05) in relative and absolute volumes of interacinar stroma, whereas ventral prostate weigh was unchanged. Irrespective of animal age, ghrelin did not affect serum testosterone levels. These are the first results of ghrelin treatment effects on healthy prostate appearance, which allow us to conclude that the rat ventral prostate response to ghrelin depends on the developmental stage of animals. Our results merit further investigations and may have clinical implications, especially in the light of data on possible role of ghrelin in prostate hypertrophy and adenomas.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 203-210.

  Comparison of blood pro/antioxidant levels before and after acute exercise in athletes and non-athletes
Dusica Djordjevic 1), Dejan Cubrilo, Nevena Barudzic, Milena Vuletic, Vladimir Zivkovic, Miroslav Nesic, Dragan Radovanovic, Dragan Djuric, Vladimir Jakovljevic

1)Department of Physiology, Faculty of Medicine, University of Kragujevac, Kragujevac, Republic of Serbia.

The aims of our study were to assess the redox state of adolescent athletes and non-athletes both at rest and after acute exposure to physical load and to find relations between parameters of redox state and morphofunctional characteristics of subjects. 58 young handball players and 37 non-athletes were subjected to body composition analysis, measuring of maximal oxygen consumption and blood sampling immediately before and after a maximal progressive exercise test. At rest, athletes had significantly higher superoxide dismutase (SOD) and catalase (CAT) activity, higher levels of glutathione (GSH) and nitric oxide (NO) and lower levels of lipid peroxidation (TBARS) compared with non-athletes. A maximal exercise test induced statistically significant rise of superoxide anion radical (O2–), hydrogen peroxide (H2O2) and NO levels in non-athletes, while TBARS levels decreased. Athletes experienced the fall in NO levels and the fall in CAT activity. After exercise, athletes had significantly lower levels of O2– compared with non-athletes. Two way repeated measures ANOVA showed that the response of O2–, NO and TBARS to the exercise test was dependent on the sports engagement (training experience) of subjects. Significant correlations between morphofunctional and redox parameters were found. These results suggest that physical fitness affects redox homeostasis.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 211-219.

  Scaling law: A global topological property of genetic sequences
Shou-Liang Bu 1)

1)School of Physics and Optical Information Technology, Jiaying University, 514015 MeiZhou, People’s Republic of China.

Here, we study the topological properties of genetic sequence by viewing the entire sequence as a whole. First, a systematic way of coding the gene-combinations in a genetic sequence is developed. Next, we apply the coding method to real genetic sequences, and find a scale-free power-law distribution for some particular kinds of gene-combinations. Furthermore, we also present a model to reproduce the observed scale-free feature, which is based on three generic mechanisms: 1) Growth mechanism – genetic sequences expands continuously by the addition of new codon; 2) Preferential replication mechanism – the newly added codon at every time step is a replication of one of existed condons, and the probability that a codon is replicated is proportional to its emerging times in existed sequence; and 3) Mutation mechanism – following (2) the newly added codon has a small probability to mutate. To our knowledge, no report has been published to study the genetic sequences in such way.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 221-224.

  Study of interaction of long-chain n-alcohols with fluid DOPC bilayers by a lateral pressure sensitive fluorescence probe
Tatiana Murugova 1), Mária Klacsová, Petra Pullmannová, Janka Karlovská, Pavol Balgavý

1)Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia.

The excimer 1,2-dipyrenedecanoyl-sn-glycero-3-phosphatidylcholine (dipy10PC) fluorescence probe was used to determine effects of aliphatic alcohols (CnH2n+1OH, n = 12–18 is the even number of carbons in alkyl chain) on fluid dioleoylphosphatidylcholine (DOPC) +dioleoylphosphatidylserine (DOPS) bilayers in multilamellar vesicles at molar ratio DOPC/DOPS = 24.7. The excimer to monomer fluorescence intensity ratio increases with the increase of CnH2n+1OH/DOPC molar ratio and decreases with the CnH2n+1OH alkyl chain length n at a constant CnH2n+1OH/DOPC = 0.4 molar ratio. These effects indicate changes in the bilayer lateral pressure on the level of pyrenyl moieties location.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 225-227.

  The role of quercetin in membrane stability
Salvatore Chirumbolo 1)

1)Department of Medicine, University of Verona, LURM-Policlinico GB Rossi, Piazzale AL Scuro 10, 37134 Verona, Italy.

General Physiology and Biophysics. Volume 31, 2012, No. 2: 229-232.

  Erratum to: Proton magnetic resonance spectroscopy and its diagnostically important metabolites in the brain
Michal Bittšanský 1), Desanka Výbohová, Dušan Dobrota

1)Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.

An incorrect sentence in the Abstract section was published on page 101. The correct sentence should be as follows: We also present a few notes on the importance of proper spectral quantification and contemporary trends in 1H MRS. Published in Gen. Physiol. Biophys. 31(1), 101–112, 2012

General Physiology and Biophysics. Volume 31, 2012, No. 2