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General Physiology and Biophysics

Volume 36, 2017, No. 1


  Ubiquitination and proteasome-mediated degradation of voltage-gated Ca2+ channels and potential pathophysiological implications
Ricardo Felix 1), Norbert Weiss

1)Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.

Recent findings have revealed a fundamental role of the ubiquitin-proteasome system (UPS) in the regulation of voltage-gated Ca2+ channels (VGCCs). It has been proposed that the ubiquitination-deubiquitination balance dictates the number of channels expressed at the plasma membrane, which in turn influences a number of physiological and pathophysiological processes. This minireview surveys recent studies showing that VGCCs may be ubiquitinated in an unexpectedly complex manner, and highlights the role of the UPS in the regulation of the channels, focusing on the mechanisms that control their cell surface expression. The exciting new findings in this emerging field suggest that the turnover of VGCCs may be determined to a large degree by the activity of the UPS, and that alteration of the UPS molecular machinery may be one of the underlying mechanisms occurring in a number of channelopathies.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 1-5.

  Influence of solar and geomagnetic activity in Gymnodinium catenatum (Dinophyceae) cultures
Paulo Vale 1)

1)The Portuguese Sea and Atmosphere Institute, I. P. (IPMA, IP), Sea and Marine Resources Department (DMRM), Avenida de Brasília s/n, 1449-006 Lisbon, Portugal.

Laboratory cultures of the paralytic shellfish poisoning producing microalga Gymnodinium catenatum were subjected to a hypo-osmotic shock and changes in cell concentration were observed in two separate experiments of 8 and 24 hours duration, respectively. The increase in geomagnetic activity (GMA), radio and X-ray fluxes and solar X-ray flares were negatively correlated with cell numbers. Cell losses were observed in the short experiment, but not in the longest one. GMA action was related to the course of the experimental period, while electromagnetic radiation (EMR) was only significantly related when the previous hours before the experiments were considered. The differential action windows might be indicative of two differential disruptive mechanisms: EMR might act on DNA synthesis and mitosis phases of the cell cycle (taking place in the dark period) and GMA might be more disruptive at the end of mytosis or cytokinesis phases taking place in the light period. Formation of long chains (> 4 cells/chain) was reduced with salinity and with temperatures above 27ºC but increased with EMR and GMA, particularly when grown at the highest temperatures recorded during the study period (≥28ºC).

General Physiology and Biophysics. Volume 36, 2017, No. 1: 7-21.

  Imaging of striatal injury in a songbird brain
Kristina Lukacova 1), Ladislav Baciak, Eva Pavukova, Katarina Pichova, Svatava Kasparova, Lubica Kubikova

1)Department of Physiology and Ethology, Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia.

Neurological insults affect both, brain structure and behavior. The injury-induced brain plasticity and associated changes in behavior are difficult to study using classical histological methods. The magnetic resonance imaging (MRI), however, enables repeated inspection of the brain in the same individual. Here we took advantage of the songbird model with discrete brain circuitry controlling song learning and production and assessed if a conventional MRI is suitable to detect even relatively small brain changes. Our aim was to monitor injury and the following regeneration in the striatal vocal nucleus Area X that controls vocal learning in juveniles and affects song in adult songbird zebra finch (Taeniopygia guttata). The regeneration process was detected using T2-weighted images and validated by immunohistochemical (IHC) staining up to 6 months after the injury. Despite the small volume of the zebra finch brain, a satisfactory signal-to-noise ratio was achieved with reasonably short measurement times. No significant difference was found between the measurements of the lesion size obtained by MRI and IHC staining. Our data show that the non-invasive MRI technique can reliably measure and quantify the regeneration process even in a relatively small part of the brain and that the avian striatum progressively regenerates after its neurotoxic injury.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 23-29.

  Esculetin exerts anti-proliferative effects against non-small-cell lung carcinoma by suppressing specificity protein 1 in vitro
Ra Lee 1), Young-Joo Jeon, Jin Cho, Jeong-Yun Jang, Il-Keun Kong, , Seok-Ho Kim, MinSeok Kim, Hak-Jae Chung, Keon Oh, Seon-Min Park, Jae-Cheon Shin, Jae-Min Seo, Sungho Ko, Jung-Hyun Shim, Jung-Il Chae

1)Department of Dental Pharmacology, School of Dentistry, BK21 Plus, Chonbuk National University, Jeonju, Republic of Korea.

Esculetin, a coumarin derivative, is a phenolic compound isolated from Artemisia capillaris, Citrus limonia, and Euphorbia lathyris. Although it has been reported to have anti-inflammatory, anti-oxidant, and anti-proliferative activities in several human cancers, its anti-proliferative activity against non-small-cell lung carcinoma (NSCLC) and the molecular mechanisms involved have not been adequately elucidated. In this study, we used two NSCLC cell lines (NCI-H358 and NCI-H1299) to investigate the anti-proliferative activity and apoptotic effect of esculetin. Our data showed that esculetin-treated cells exhibited reduced proliferation and apoptotic cell morphologies. Intriguingly, the transcription factor specificity protein 1 (Sp1) was significantly suppressed by esculetin in a dose- and time-dependent manner. Furthermore, the levels of p27 and p21, two key regulators of the cell cycle, were up-regulated by the esculetin-mediated down-regulation of Sp1; the level of a third cell-cycle regulator, survivin, was decreased, resulting in caspase-dependent apoptosis. Therefore, we conclude that esculetin could be a potent anti-proliferative agent in patients with NSCLC.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 31-39.

  The influence of prenatal 10 GHz microwave radiation exposure on a developing mice brain
Archana Sharma 1), Kavindra Kesari, Virender Saxena, Rashmi Sisodia

1)Neurobiology Laboratory, Department of Zoology, University of Rajasthan, Jaipur, India.

Our objective was to investigate alterations in the developing mice brain after intrauterine microwave exposure from different gestation days (0.25 and 11.25) till term. Pregnant mice from 0.25 and 11.25 days of gestation were isolated from an inbred colony and divided into sham-exposed (control) and microwave-exposed (10 GHz) groups. The follow-up study of mice at 3 weeks of age showed significant reduction in the brain and body weight of microwave-exposed group. Results showed an increased level of lipid peroxidation, decreased level of glutathione and protein after microwave exposure on both 0.25 and 11.25 day of gestation. Moreover, changes in cytoarchitechure of hippocampus and cerebellum of the brain and reduction in Purkinje cell number were observed statistically significant after microwave exposure from both 0.25 and 11.25 days of gestation. In conclusion, the degree of severity of damage in neonatal mice brain was much higher, when exposure started from 0.25 day of gestation compared to 11.25 days of gestation.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 41-51.

  The effect of maternal stress on blastocyst quality depends on maternal physiological status
Žofia Janštová 1), Ján Burkuš, Janka Kubandová, Dušan Fabian, Juraj Koppel, Štefan Čikoš

1)Institute of Animal Physiology, Slovak Academy of Sciences, Šoltésovej 4, 04001 Košice, Slovak Republic.

The effect of maternal stress on blastocyst quality, with respect to maternal metabolic status, was investigated in this study. We exposed female mice with different amounts of body fat to restraint stress and examined their blastocyst quality. Blood concentrations of corticosterone, leptin, adiponectin, insulin and glucose were measured in these females. Significantly lower stress-induced corticosterone elevations were observed in females with high and low amounts of body fat, indicating that the stress response was altered in these females. The basal leptin concentrations were significantly higher in females with high amounts of body fat than in females with low amounts of body fat, and stress induced different responses in these two groups of females. Our results showed that maternal stress can significantly increase the proportion of blastocysts that contain dead (apoptotic) cells in females with high and medium amounts of body fat. In females with low amounts of body fat, the proportion of blastocysts containing dead (apoptotic) cells was already increased before the stress exposure, and application of stress did not significantly change this parameter. Our results showed that the effects of maternal stress on early embryos can depend on the actual physiological status of the maternal organism exposed to stress.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 53-63.

  Sinomenine prevents the development of cardiomyopathy in diabetic rats by inhibiting inflammatory responses and blocking activation of NF-κB
Cheng Jiang 1), Yun-Long Tong, Dan Zhang, Li-Zhi Liu, Ju-Fei Wang

1)Department of Vasculocardiology, Fenghua people's hospital, 315500 Ningbo, China.

Diabetic cardiomyopathy is a severe complication of diabetes mellitus (DM). The goal of current work was to study the effects of sinomenine on streptozotocin-induced cardiomyopathy in rats. DM in rats was induced by intraperitoneal injection of streptozotocin. Cardiac function was evaluated by measuring left ventricle end-diastolic diameter, left ventricle end-systolic diameter and ejection fraction. Cardiac inflammation was evaluated by the degree of infiltration of T lymphocytes and the levels of pro-inflammatory cytokines. Sinomenine attenuated diabetic symptoms without affecting plasma glucose. Cardiac dysfunction in the sinomenine-treated diabetic rats was significantly improved, as reflected by decreased levels of left ventricle end-diastolic diameter, left ventricle end systolic diameter and an increased level of ejection fraction. Sinomenine observably reduced cardiomyocyte hypertrophy in DM rats. Moreover, sinomenine reduced infiltration of CD3+ and CD68+ positive cells and decreased the levels of tumor necrosis factor-α, interlukin-1 and interlukin-6. Finally, sinomenine-treated rats showed a reduced expression of NF-κB and an increased expression of IκB in the myocardium compared with the myocardium of untreated diabetic rats. Our results indicate sinomenine significantly improves cardiac function in diabetic rats, which may be attributed to the deactivation of NF-κB and the blockade of inflammatory cytokine-mediated immune reactions.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 65-74.

  The response of rat and human uterus to oxytocin from different gestational stages in vitro
Mohammed Alotaibi 1)

1)Department of Physiology, College of Medicine, King Saud University and King Khalid University Hospital, P.O. Box 2925, Riyadh 11461, Kingdom of Saudi Arabia.

Oxytocin (OT) and oxytocin receptors (OTRs) play essential roles in parturition and the effect of OT on uterine contractility is greatly influenced by the expression of OTRs in myometrium. We investigated the effect of OT on uterine strips isolated from non-pregnant, late-pregnant, term-pregnant, and labouring rats and from labouring and non-labouring women. Longitudinal uterine strips (from each gestational stage) were dissected and mounted vertically in an organ bath setup system and challenged with 5 nM OT and the effect was investigated on uterine contractility. In other experiments, phospholipase C (PLC), prostaglandin H synthase-2 (PGHS-2), and calcium-activated chloride channels (CaCCs) were blocked and the effect of OT was tested in labouring rats. OT stimulated the labouring uterus with greater force compared to other gestations in rats and also augmented the uterine force in labouring women compared to the non-labouring. However, blocking the PLC, PGHS-2, and CaCCs significantly reduced the OT-induced force increase in labouring rats. These data suggest that as labour approaches, the sensitivity of the uterine tissues to OT is greatly enhanced concomitant with the increased expression of OTR to ensure strong and adequate uterine contractions essential for the normal delivery and to prevent the postpartum haemorrhage.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 75-82.

  Effects of low and high deprenyl dose on antioxidant enzyme activities in the adult rat brain
Maria Lalkovicova 1), Frantiska Horvathova, Igor Sulla, Jozef Mihalik, Viera Danielisova

1)Institute of Neurobiology, Slovak Academy of Sciences, Kosice, Slovakia.

We evaluated the effects of low dose deprenyl (LDD, 0.0025 mg/kg per day) and high dose deprenyl (HDD, 0.25 mg/kg per day) treatment of male Wistar rats for 30 days on the activities of SOD and CAT in the cortex, striatum, and hippocampus. Total SOD and MnSOD activities were increased with LDD (p <0.05) in the cortex (0.74 ± 0.03; 0.31 ± 0.02), striatum (0.75 ± 0.02; 0.27 ± 0.03) and CA1 region of the hippocampus (0.75 ± 0.02; 0.29 ± 0.03) compared to the control (0.53 ± 0.02; 0.15 ± 0.02), but reduced (p <0.05) with HDD compared to the LDD group. CAT activity was increased (p <0.05) with LDD in the cortex (27.34 ± 3.11), striatum (22.22 ± 1.85), and hippocampal CA1 region (16.62 ± 2.15) compared to control (10.33 ± 1.01), while a decrease was induced by HDD in the striatum (9.85 ± 1.09) compared to LDD. There was a significant (p <0.05) difference in number of Fluoro Jade B positive CA1 neurons induced by LDD (21.14 ± 2.85%) and HDD (12.61 ± 1.42%), as well as the number of NeuN positive CA1 neurons after LDD (183.35 ± 11.14 cells/mm) and HDD (238.45 ± 14.11 cells/mm (p < 0.05). Deprenyl showed a potential in improving the neurological outcome and reducing the oxidative damage.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 83-90.

  Integrated in silico-in vitro characterization, identification and disruption of the intermolecular interaction between SH3 domain-containing protein kinases and human pituitary tumor-transforming gene 1
Yanan Li 1), Mengmeng Li, Weijie Min, Guosheng Han, Laixing Wang, Chao Chen, Zifu Li, Yuhui Zhang, Jianmin Li, Zhijian Yue

1)Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.

The human pituitary tumor-transforming gene-1 (hPTTG1) has been found to be overexpressed in various cancers. Accumulated evidences implicate that some of protein kinases can specifically recognize two PXXP motifs at hPTTG1 C-terminus through their Src homology (SH3) domain and then phosphorylate the protein by their catalytic domain. Here, we integrate in silico analysis and in vitro assay to characterize the intermolecular interaction between the two hPTTG1 motif peptides 161LGPPSPVK168 (M1P) and 168KMPSPPWE175 (M2P) and the SH3 domains of Ser/Thr-specific protein kinases MAP3K and PI3K. It is identified that the two peptides bind to MAP3K SH3 domain with a moderate affinity, but cannot form stable complexes with PI3K SH3 domain. Long time scale molecular dynamics (MD) simulations reveal that the M1P peptide can fold into a standard poly-proline II helix that is bound in the peptide-binding pocket of MAP3K SH3 domain, while the M2P peptide gradually moves out of the pocket during the simulations and finally forms a weak, transient encounter complex with the domain. All these suggest that the MAP3K M1P site is a potential interacting partner of MAP3K SH3 domain, which may mediate the intermolecular recognition between hPTTG1 and MAP3K.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 91-98.

  Cerebellar neurochemical and histopathological changes in rat model of Parkinson’s disease induced by intrastriatal injection of rotenone
Yasser Khadrawy 1), Iman Mourad, Haitham Mohammed, Neveen Noor, Heba Aboul Ezz

1)Medical Physiology Department, Medical Division, National Research Center, Giza, Egypt.

The aim of the present work was to investigate the neurochemical changes induced in the cerebellum of rat model of Parkinson’s disease (PD). Rats were divided into two groups; control and rat model of PD induced by the intrastriatal injection of rotenone. As compared to control, a significant increase in the excitatory amino acid neurotransmitters; glutamate and aspartate together with a significant decrease in the inhibitory amino acids, GABA, glycine and taurine were observed in the cerebellum of rat model of PD. This was associated with a significant increase in lipid peroxidation, nitric oxide and tumor necrosis factor-α and a significant decrease in reduced glutathione. A significant decrease in acetylcholinesterase and a significant increase in Na+,K+-ATPase were recorded in the cerebellum of rat model of PD. In addition the cerebellar sections from rat model of PD showed marked necrosis of Purkinje cells, irregular damaged cells, cytoplasmic shrinkage, necrosis and perineuronal vacuolation. The present results indicate that the disturbance in the balance between the excitatory and inhibitory amino acids may have a role in the pathogenesis of PD. According to the present neurochemical and histopathological changes, the cerebellum should be taken into consideration during the treatment of PD.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 99-108.

  Obestatin improves hepatic injury induced by ischemia/reperfusion in rats: Role of nitric oxide
Ola El-Gohary 1)

1)Physiology Department, Faculty of Medicine, Benha University, Benha, Qualubia, Egypt.

Hepatic ischemia/reperfusion (I/R) injury is a common clinical problem. The present study was conducted to evaluate the protective effect of obestatin against I/R-induced liver injury. Rats were divided into three groups (n = 10): control sham-operated group, I/R group and obestatin treatment group. Rats of I/R group and obestatin treatment group underwent partial hepatic ischemia for 60 min followed by 90 min reperfusion. At the beginning of the 90-min reperfusion period, rats of obestatin treatment group were injected with obestatin (100 μg/kg) intravenously. At the end of the experiment the animals were sacrificed and blood and liver tissue samples were obtained. Liver function enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as inflammatory biomarkers, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), were determined in the serum. Also, total oxidative status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI) were measured in hepatic tissue. Liver tissue damage was examined by histopathology. In addition, the expression levels of nitric oxide synthase (NOS) subtypes, endothelial (eNOS) and inducible (iNOS) in liver samples were assessed by Western blotting. Obestatin significantly counteracted I/R-induced liver damage mainly through reducing oxidative stress, inhibiting the release of pro-inflammatory cytokines and modulation of nitric oxide levels.

General Physiology and Biophysics. Volume 36, 2017, No. 1: 109-115.