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Effect of melatonin supplementation on pregnancy outcome in Wistar-Kyoto and Sprague-Dawley rats.

Harbindar Jeet SINGH ; Hisham Ibrahim SALEH ; Sergey GUPALO ; Effat OMAR

Acta Physiologica Sinica.2013;65(2):149-157.

Although melatonin supplementation is known to influence numerous physiological functions, little is however known of its effects on pregnancy outcome. This study investigated the effects of melatonin supplementation on pregnancy outcome in Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats aged 12-13 weeks. Upon confirmation of proestrus, each female rat was housed overnight with a male of the same strain. On the next morning, following confirmation of mating (vaginal smear), WKY female rats were isolated into individual metabolic cages and given 0, 25, 50 or 100 mg/kg per day of melatonin in drinking water from day 1 of pregnancy to day 21 postpartum. SD females were given 0 or 100 mg/kg per day of melatonin. Maternal weight, duration of pregnancy, litter size, birth weight and body weight of pups up to day 42, and pup mortality were recorded. Data were analyzed using ANOVA for repeated measures. Compared to controls, maternal weight gain during pregnancy was significantly lower in melatonin-supplemented dams (P < 0.01). Litter size was significantly smaller in melatonin-supplemented dams (P < 0.01). Mean birth weight of pups was significantly lower only in pups of dams given 100 mg/kg per day of melatonin (P < 0.001). Mean body weight of pups of dams given melatonin was significantly lower than controls (P < 0.01). Pup mortalities were 9.5% and 21.6% in WKY dams given 25 and 100 mg/kg per day of melatonin respectively, and all pup deaths occurred after day 21 of weaning. The results suggest that melatonin supplementation during antenatal and postpartum period appears to adversely affect litter size, pup growth and mortality in WKY and SD rats. The precise mechanism causing the death is not clear.
Animals ; Body Weight ; Female ; Litter Size ; Melatonin ; pharmacology ; Pregnancy ; Pregnancy Outcome ; Pregnancy, Animal ; drug effects ; Rats ; Rats, Inbred WKY ; Rats, Sprague-Dawley ; Weaning

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Four-week simulated weightlessness increases the expression of atrial natriuretic peptide in the myocardium.

Wen-Cheng ZHANG ; Yuan-Ming LU ; Huai-Zhang YANG ; Peng-Tao XU ; Hui CHANG ; Zhi-Bin YU

Acta Physiologica Sinica.2013;65(2):143-148.

One of the major circulatory changes that occur in human during space flight and simulated weightlessness is a cerebral redistribution of body fluids, which is accompanied by an increase of blood volume in the upper body. Therefore, atrial myocardium should increase the secretion of atrial natriuretic peptide (ANP), but the researches lack common conclusion until now. The present study was to investigate the expression level of ANP in simulated weightlessness rats, and to confirm the changes of ANP by observing the associated proteins of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). The tail-suspended rat model was used to simulate weightlessness. Western blots were carried out to examine the expression levels of ANP and SNARE proteins in atrial and left ventricular myocardium. The results showed that ANP expression in atrial myocardium showed an increase in 4-week tail-suspended rats (SUS) compared with that in the synchronous control rats (CON). We only detected a trace amount of ANP in the left ventricular myocardium of the CON, but found an enhanced expression of ANP in left ventricular myocardium of the SUS. Expression of VAMP-1/2 (vesicle associated SNARE) increased significantly in both atrial and left ventricular myocardium in the SUS compared with that in the CON. There was no difference of the expression of syntaxin-4 (target compartment associated SNARE) between the CON and SUS, but the expression of SNAP-23 showed an increase in atrial myocardium of the SUS compared with that in the CON. Synip and Munc-18c as regulators of SNAREs did not show significant difference between the CON and SUS. These results suggest that the expression of ANP shows an increase in atrial and left ventricular myocardium of 4-week tail-suspended rats. Enhanced expression of VAMP-1/2 associated with ANP vesicles confirms the increased expression of ANP in atrial and left ventricular myocardium.
Animals ; Atrial Natriuretic Factor ; metabolism ; Heart Ventricles ; metabolism ; Myocardium ; metabolism ; Rats ; SNARE Proteins ; metabolism ; Vesicle-Associated Membrane Protein 1 ; metabolism ; Vesicle-Associated Membrane Protein 2 ; metabolism ; Weightlessness Simulation

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Migratory properties of vascular smooth muscle cells on extracellular matrix: a study on inverted coverslip migration assay.

Feng WANG ; Gui-Qin WANG ; Feng XUE ; Zhao-Qin CHEN ; Yong-Sheng GONG ; Zhi-Hui HUANG

Acta Physiologica Sinica.2013;65(2):135-142.

Migration of vascular smooth muscle cells (VSMCs) is involved in vascular development and various vascular diseases; however, the molecular mechanisms of VSMC migration remain unclear. In this study, we established an inverted coverslip migration assay to study the migratory properties of cultured VSMCs on extracellular matrix. Pulmonary arterial smooth muscle cells (PASMCs) from rats were cultured and identified by immunocytochemistry. Each coverslip with a confluent monolayer of PASMCs was inverted to a larger coverslip which was coated with phosphate buffered saline (PBS, as a control), poly-D-lysine hydrobromide (PDL), laminin or Matrigel. After 24 h of migration over the larger coverslip, PASMCs were fixed, and reliably quantified. The roles and mechanisms of extracellular matrix in PASMC migration were further studied by wound-healing assay and immunocytochemistry. The results showed that: (1) The purity of the cultured PASMCs was (97 ± 3)%. (2) The number of PASMCs on laminin or Matrigel migrating out from the inverted coverslip was significantly increased compared with that on PBS or PDL, and the migratory distance of PASMCs on laminin or Matrigel was significantly farther than that on PBS or PDL. (3) The motility of PASMCs on laminin or Matrigel was significantly higher than that on PBS at 8 h, 12 h and 24 h after wounding, respectively. (4) F-actin staining showed that F-actin was congregated along the brim of the migrating cells from the inverted coverslip, and vinculin (a cell marker of focal adhesion) staining showed that the distribution of vinculin in PASMCs plated on laminin or Matrigel was significantly lower than that on PBS or PDL. These results suggest that the inverted coverslip migration assay is suitable to study VSMC migration, and laminin and Matrigel substrates may promote VSMC migration through inhibiting the formation of focal adhesion and regulating the cytoskeletal proteins.
Actins ; chemistry ; Animals ; Cell Adhesion ; Cell Movement ; Cells, Cultured ; Collagen ; chemistry ; Drug Combinations ; Extracellular Matrix ; chemistry ; Laminin ; chemistry ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; cytology ; Proteoglycans ; chemistry ; Pulmonary Artery ; cytology ; Rats

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Inhibitory effects of endocannabinoid on the action potential of pacemaker cells in sinoatrial nodes of rabbits.

Jiao ZHANG ; San-Yi WANG ; Jing-Jing ZHOU ; Yan WEI ; Qian LI ; Jing YANG ; Yi ZHANG

Acta Physiologica Sinica.2013;65(2):129-134.

Endocannabinoid anandamide (AEA) has protective effect on the heart against ischemia/reperfusion injury and arrhythmia, but the electrophysiological mechanism is unclear yet. In this study, the sinoatrial node (SAN) samples from New Zealand rabbits were prepared, and intracellular recording technique was used to elucidate the effect of AEA on the action potential (AP) of SAN pacemaker cells of rabbits and the mechanism. Different concentrations of AEA (1, 10, 100, 200, 500 nmol/L) were applied cumulatively. For some SAN samples, cannabinoid type 1 (CB1) receptor antagonist AM251, cannabinoid type 2 (CB2) receptor antagonist AM630, potassium channel blocker tetraethylammonium (TEA) and nitric oxide (NO) synthase inhibitor L-nitro-arginine methylester (L-NAME) were used before AEA treatment, respectively. We found that: (1) AEA (100, 200 and 500 nmol/L) not only shortened AP duration (APD), but also decreased AP amplitude (APA) (P < 0.05). (2) AM251, but not AM630, abolished the effect of AEA on APD shortening. (3) TEA and L-NAME had no influence on the AEA effect. These findings suggest that anandamide can decrease APA and shorten APD in SAN pacemaker cells of rabbits, which may be mediated by activation of CB1 receptors, and is related to blockade of calcium channels but not potassium channels and NO.
Action Potentials ; Animals ; Arachidonic Acids ; pharmacology ; Cannabinoid Receptor Antagonists ; pharmacology ; Endocannabinoids ; pharmacology ; Indoles ; pharmacology ; Myocytes, Cardiac ; drug effects ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Piperidines ; pharmacology ; Polyunsaturated Alkamides ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Pyrazoles ; pharmacology ; Rabbits ; Sinoatrial Node ; cytology

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Contraction responses of isolated aortic rings of pika (Ochotona curzoniae) and Sprague-Dawley rat to hypoxia.

Shuang MA ; Yan MA ; Ri-Li GE

Acta Physiologica Sinica.2013;65(2):122-128.

The aim of the present study was to observe the effects of hypoxia on tensions of aortic rings of pika (Ochotona curzoniae) and Sprague-Dawley (SD) rat. The aortic rings were prepared, and in vitro vascular ring perfusion was used to assay the effects of hypoxia or different drugs on contraction responses of the rings with or without endothelium. The results showed that, there was no difference of the contractions to KCl (80 mmol/L) between the aortic rings of the pikas and SD rats. After pre-contraction with NE (1 μmol/L), the aortic rings with endothelium of the SD rats showed obvious relaxation to ACh (1 μmol/L), whereas the aortic rings of the pikas, no matter with or without endothelium, showed significant and unusual contraction to ACh. The aortic rings of pikas, no matter with or without endothelium, exhibited greater contraction when treated by 1 h of hypoxia, compared with those in SD rats; The similar result was showed under hypoxia in combination with Ca(2+) removal. These results suggest that the contraction response to hypoxia in pika is more sensitive compared to that in SD rat, which is dependent on the release of calcium from intracellular calcium store.
Animals ; Aorta, Thoracic ; physiology ; Arterial Pressure ; Calcium ; physiology ; Hypoxia ; In Vitro Techniques ; Lagomorpha ; Rats ; Rats, Sprague-Dawley

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RhoA-Rho kinase signaling pathway mediates adventitial fibroblasts differentiation to myofibroblasts induced by TGF-β1.

Wen-Dong CHEN ; Yu-Feng CHU ; Jian-Jun LIU ; Mo-Na HONG ; Ping-Jin GAO

Acta Physiologica Sinica.2013;65(2):113-121.

Vascular adventitial fibroblasts (AF) differentiation to myofibroblasts (MF) is the critical physiopathologic feature of vascular remodeling. This study was to investigate the role of RhoA-Rho kinase signaling pathway in AF differentiation to MF induced by transforming growth factor β1 (TGF-β1). The results showed that TGF-β1 up-regulated total RhoA protein expression and RhoA activity in cultured AF by Western blotting and Rho pull-down assay, respectively. TGF-β1 up-regulated phospho-Myosin phosphatase target subunit (MYPT1, a downstream substrate of Rho kinase) expression without altering Rho kinase protein expression, indicating TGF-β1 induced the enhancement of activity of Rho kinase. Ad-N19RhoA-hrGFP virus infection and Y27632, a specific inhibitor of Rho kinase, dose-dependently inhibited TGF-β1-induced α-SM-actin and Calponin expression, as markers of MF differentiation. In conclusion, the RhoA-Rho kinase pathway is involved in AF differentiation to MF induced by TGF-β1.
Actins ; metabolism ; Adventitia ; cytology ; Calcium-Binding Proteins ; metabolism ; Cell Differentiation ; Cells, Cultured ; Fibroblasts ; cytology ; Microfilament Proteins ; metabolism ; Myofibroblasts ; cytology ; Signal Transduction ; Transforming Growth Factor beta1 ; pharmacology ; Up-Regulation ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

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Behavioral and neurobiological abnormalities induced by social isolation as a useful animal model of schizophrenia.

Ming LEI ; Lu LUO ; Shi-Qi MA ; Yan ZHANG ; Xi-Hong WU ; Liang LI

Acta Physiologica Sinica.2013;65(1):101-108.

Social isolation influences the development of the brain, causing dysfunctions at behavioral, cellular and molecular levels. The present paper summarizes the abnormalities induced by social isolation in behaviors, neurotransmitters and cell apoptosis. At the behavioral level, social isolation induces hyperlocomotion, abnormalities in startle reflex and prepulse inhibition (PPI), and dysfunctions in conditioned learning, reversal learning and memory. Moreover, social isolation causes changes of neurotransmitters, such as the increase of dopamine in the nucleus accumbens, the amygdala and other brain regions in the limbic system, the decrease of dopamine in medial prefrontal cortex, the decrease of 5-HT in the nucleus accumbens and the hippocampus, and changes of glutamine in the prefrontal cortex. Finally, social isolation affects cell apoptosis in different brain areas, such as the medial prefrontal cortex, amygdala, nucleus accumbens, and hippocampus. Both the changes in neurotransmitters and cell apoptosis may contribute to the behavioral dysfunctions in social isolated rats. Since schizophrenic patients have similar abnormalities in behaviors and neurotransmitters, isolation rearing can be used as a useful animal model of schizophrenia.
Animals ; Brain ; physiopathology ; Disease Models, Animal ; Neurotransmitter Agents ; metabolism ; Rats ; Schizophrenia ; physiopathology ; Social Isolation

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Relationship between simulated weightlessness-induced muscle spindle change and muscle atrophy.

Xue-Hong ZHAO ; Xiao-Li FAN

Acta Physiologica Sinica.2013;65(1):96-100.

One of the most important and urgent issues in the field of space medicine is to reveal the potential mechanism underlying the disused muscle atrophy during the weightlessness or microgravity environment. It will conduce to find out effective methods for the prevention and treatment of muscle atrophy during a long-term space flight. Increasing data show that muscle spindle discharges are significantly altered following the hindlimb unloading, suggesting a vital role in the progress of muscle atrophy. In the last decades, we have made a series of studies on changes in the morphological structure and function of muscle spindle following simulated weightlessness. This review will discuss our main results and related researches for understanding of muscle spindle activities during microgravity environment, which may provide a theoretic basis for effective prevention and treatment of muscle atrophy induced by weightlessness.
Animals ; Hindlimb Suspension ; Muscle Spindles ; physiopathology ; Muscle, Skeletal ; physiopathology ; Muscular Atrophy ; physiopathology ; Space Flight ; Weightlessness Simulation

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Effects of SUMOylation on the subcellular localization and function of DAXX.

Ling LI ; Juan WEN ; Qin-Hui TUO ; Duan-Fang LIAO

Acta Physiologica Sinica.2013;65(1):89-95.

Death domain-associated protein (DAXX) as a multifunctional nuclear protein widely resides in nucleolus, nucleoplasm, chromatin, promyelocytic leukaemia nuclear bodies (PML-NBs) and cytoplasm. It plays significant roles in transcriptional regulation, apoptosis, cell cycle and other biological activities. Small ubiquitin-like modifier (SUMO) is required for SUMOylation which is a highly conserved post-translational modification in a wide variety of cellular processes. Numerous studies demonstrated that SUMOylation has a great effect on the subcellular localization and functional regulation of DAXX. This review will provide a summary for SUMOylation of DAXX.
Adaptor Proteins, Signal Transducing ; physiology ; Gene Expression Regulation ; Humans ; Nuclear Proteins ; physiology ; Sumoylation

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Metabolites of long-time preserved-acutely isolated rat cardiomyocytes affect L-type Ca(2+) channel current.

Zhi-Jie YUE ; Juan-Juan SHENG ; Man-Jiang XIE ; Zhi-Bin YU

Acta Physiologica Sinica.2013;65(1):83-88.

The variability of peak current of L-type calcium channel (I(Ca,L)) shows an increase in cardiomyocytes after 6 h of preservation when the acutely isolated cardiomyocytes are preserved in a small volume buffer solution. The mechanism of the increased variability of I(Ca,L) is not clear. In order to obtain more accurately and stably experimental data of I(Ca,L), the aim of this study was to observe the pH changes of preservation buffer solution with acutely isolated rat cardiomyocytes, and the effects of pH changes on the shape of cardiomyocytes, the function of mitochondria and the gating property of L-type calcium channel. The results indicated that the pH was kept stable in 100 mL buffer solution, but was decreased from 7.20 to 6.95 in 20 mL buffer solution during 10 h of cardiomyocyte preservation. Therefore, 100 mL or 20 mL preservation solution was used as a normal control or acidotic group, respectively. The ratio of abnormal to normal rod-shaped cardiomyocytes increased in the acidotic group after 6 h of preservation. The acidosis induced a reduction in mitochondrial membrane potential indicated by JC-1 fluorescent probe after 8 h of cardiomyocyte preservation. The acidosis also shifted the autofluorescence of NADPH from blue to green after 8 h of cardiomyocyte preservation. The above changes in mitochondrial function induced a significant decrease in the peak I(Ca,L) and a shift in the clamped voltage at peak I(Ca,L) from +10 mV to 0 mV, after 10 h of cardiomyocyte preservation. These results suggest that the best way to preserve acutely isolated cardiomyocytes is to use a larger volume buffer system. In order to get stable peak I(Ca,L), we need to not only select a normal shape of cardiomyocyte at a bright field but also a blue fluorescent myocyte at an ultraviolet excitation.
Animals ; Buffers ; Calcium Channels, L-Type ; physiology ; Cells, Cultured ; Membrane Potential, Mitochondrial ; Myocytes, Cardiac ; physiology ; Preservation, Biological ; Rats

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