GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Dietary Fish Oil Protects Against Stretch-Induced Vulnerability to Atrial Fibrillation in a Rabbit Model (2005)
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 16 (2005), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Dietary fish oil is thought to reduce sudden cardiac death by suppressing ventricular arrhythmias but little is known about its impact on atrial arrhythmias. We examined the effect of dietary fish oil on the rabbit model of stretch-induced vulnerability to atrial fibrillation (AF). Methods and Results: Six-week-old rabbits were fed standard rabbit pellets supplemented with 5% tuna fish oil (n = 6) or supplemented with 5% sunflower oil (n = 6) for 12 weeks. Six rabbits raised on the standard diet were used as controls. In Langendorff-perfused hearts intraatrial pressures were increased in a stepwise manner and rapid burst pacing applied to induce AF at increasing intraatrial pressures until AF was sustained (〉1 minute). Atrial refractory periods were recorded at each pressure. Increased atrial pressure resulted in a reduction in atrial refractory period and a propensity for induction of sustained AF. Higher pressures were needed to induce and sustain AF in the fish oil group compared with the sunflower oil and control groups. The stretch-induced drop in refractory period was also less marked in the fish oil group. Red blood cell, atrial, and ventricular omega-3 fatty acid levels were significantly higher in the fish oil group. The ratio of atrial n-6/n-3 polyunsaturated fatty acids was 13 ± 0.9 with sunflower oil and 1.5 ± 0.01 with fish oil (P 〈 0.001). Conclusions: Incorporation of dietary omega-3 fatty acids into atrial tissue reduces stretch-induced susceptibility to AF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8167.2005.50007.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    PROPOFOL BLOCK OF CARDIAC SODIUM CURRENTS IN RAT ISOLATED MYOCARDIAL CELLS IS INCREASED AT DEPOLARIZED RESTING POTENTIALS (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 25 (1998), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The effect of propofol on cardiac whole-cell sodium currents and single sodium channels in rat isolated ventricular myocytes was examined using patch-clamp techniques.2. Propofol caused a block of the whole-cell sodium current, the potency of block depending on the holding potential. When cells were held at -90 mV, the EC50 was 2.8 μg/mL. When cells were held more hyperpolarized (at -140 mV), the EC50 increased to 44.0 μg/mL.3. Although the degree of block produced by the same concentration of propofol was different at different holding potentials, the time course of onset and recovery from block was the same.4. The current/voltage relationship for the sodium current showed a pronounced block of peak current by propofol (40–50 % block of the maximum current by 30 μg/mL propofol), with a minimal shift in the voltage dependence of activation and no shift in reversal potential.5. The voltage dependence of the steady state inactivation curve was shifted to more hyperpolarized potentials by propofol (shift of 18 and 8 mV by 30 and 10 μg/mL propofol, respectively).6. Single channel records showed that propofol caused a shortening of the mean channel open time (from a mean of 0.59 to 0.38 ms by 10 μg/mL propofol), but no change in the channel amplitude.7. It is concluded that propofol produces a block of sodium currents in cardiac myocytes at concentrations that are comparable to those that may be attained during anaesthesia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1681.1998.tb02360.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    BLOCK OF Na+ AND K+ CURRENTS IN RAT VENTRICULAR MYOCYTES BY QUINACAINOL AND QUINIDINE (2005)
    Oxford, UK : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 32 (2005), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The electrophysiological actions of quinacainol were investigated on sodium (INa), transient outward (ito) and sustained-outward plateau (iKsus) potassium currents in rat isolated cardiac myocytes using the whole-cell patch-clamp technique and compared with quinidine.2. Quinacainol blocked sodium currents in a concentration-dependent manner and with a potency similar to that of quinidine (mean (±SEM) EC50 50 ± 12 vs 95 ± 25 µmol/L for quinidine and quinacainol, respectively). However, quinacainol had a considerably prolonged onset and recovery from block compared with quinidine.3. Neither quinacainol nor quinidine significantly changed the steady state voltage dependence of activation of sodium currents. Quinidine produced a hyperpolarizing shift in the voltage dependence for sodium current inactivation, but no such shift was observed with quinacainol at doses that produced a substantial current block.4. Although quinacainol did not effectively block voltage-dependent potassium currents, even at concentrations as high as 1.5 mmol/L, quinidine, at a half-maximal sodium channel-blocking concentration, reduced peak ito current amplitude, increased the rate of inactivation of ito and blocked iKsus.5. These results indicate that quinacainol, a quinidine analogue, blocks sodium currents in cardiac myocytes with little effect on ito or iKsus potassium currents, which suggests that quinacainol may be exerting class 1c anti-arrhythmic actions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1681.2005.04149.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    PACEMAKING IN THE HEART: THE INTERPLAY OF IONIC CURRENTS (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 25 (1998), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. There is still a degree of controversy about which currents drive pacemaking in the sinoatrial node or sinus venosus. Early attempts to identify a single ‘pacemaker current’ in these tissues, based on voltage-clamp data, were largely unsuccessful, prompting the search for other mechanisms that may contribute to rhythmic activity.2. Whole-cell patch-clamp recording from single cells isolated from the sinus venosus of the toad has shown that a voltage-dependent sodium current may play a role in pacemaking. This current has a transient component that contributes to the action potential upstroke and an inactivation-resistant component that contributes to the diastolic depolarization. The relative importance of this current in pacemaking is still controversial.3. The development of computer models of pacemaking has contributed greatly to our understanding of how ionic currents can interact to produce rhythmic activity. Results are presented from one such model, ‘Oxsoft Heart', to illustrate the different contributions of If and INA and to highlight the concept that pace-making is driven by the integrated activity of many processes, rather than by any one current in particular.4. Present models of pacemaking fail to accurately reproduce biological observations for certain situations. It is becoming clear that many processes contribute to pacemaking and have yet to be fully incorporated into models. Recent results regarding the role of intracellular calcium buffering and release and their implications, are discussed in this context.5. The control of pacemaking by neurotransmitters is discussed. The limitations of single cell models in reproducing many of the complex responses to nerve stimulation of multicellular tissue, such as postinhibitory rebound, are discussed and possible improvements to models are suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1681.1998.tb02165.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Heterogeneity Of The Properties Of INa in Epicardial And Endocardial Cells Of Rat Ventricle (2002)
    Melbourne, Australia : Blackwell Science Asia Pty. Ltd.
    Clinical and experimental pharmacology and physiology 29 (2002), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Ventricular INa heterogeneity was investigated in adult rat hearts. Differences in transient outward potassium current (Ito) were used to confirm isolation of subepicardial and subendocardial cells. Mean peak Ito was 6.0 ± 0.7 and 1.6 ± 0.45 pA/pF in epicardial and endocardial cells, respectively (P 〈 〈 0.01).2. Maximum sodium conductance was smaller in subendocardial cells compared with subepicardial cells (2.39 ± 0.11 vs 2.78 ± 0.12 nS/pF, respectively; n = 17 for both; 0.01 〈 P 〈 0.05) and 50% activation occurred at a slightly more negative potential (–47.6 ± 0.8 vs–44.9 ± 0.9 mV, respectively; n = 10 for both; 0.01 〈 P 〈 0.05).3. The potential for 50% inactivation was not significantly different in subepicardial compared with subendocardial cells (72.2 ± 1.0 vs 72.8 ± 2.2 mV, respectively; n = 17 for both; NS).4. Persistent sodium current density appeared smaller in subendocardial (n = 19) compared with subepicardial (n = 11) cells (at a test potential of –25 mV current, density was 0.118 ± 0.041 vs 0.144 ± 0.085 pA/pF, respectively), although this was not statistically significant due to large variability between cells.5. Mathematical modelling of the cardiac action potential indicated that the combined effects of differences in current density and voltage dependence of sodium currents are unlikely to contribute to ventricular action potential heterogeneity between epicardial and endocardial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1681.2002.03620.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Anion permeability of motor nerve terminals (1987)
    Springer
    Pflügers Archiv 409 (1987), S. 258-264 
    Details
    ISSN: 1432-2013
    Keywords: Nerve terminal ; Anion permeability ; Transmitter release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Motor nerve terminals in mouse and frog display behavior consistent with an appreciable permeability of the nerve terminal membrane to chloride. In mouse diaphragm, in the presence of 15 mM K+ and 2 mM or 8 mM Ca2+, replacement of Cl− by NO 3 − , Br− or acetate causes a transient increase in the quantal release of acetylcholine, measured as the frequency of spontaneously occurring miniature end plate potentials (FMEPP); a rapid rise in FMEPP is followed by a slow decline, with a half-time of about 4 min, to an equilibration level close to the control level. After equilibration in a solution in which the Cl− is replaced by another anion, return to Cl−-containing solution causes a transient decrease in FMEPP with a subsequent slow recovery. The data are consistent with transient nerve terminal depolarization or hyperpolarization, reflecting a nerve terminal permeability to anions in the sequence Cl−〉Br−〉NO 3 − 〉acetate. In 5 mM K+, changes in nerve terminal excitability, determined using focal stimulation, are also consistent with alteration of nerve terminal membrane potential as a consequence of anion substitution. The time course of relaxation of FMEPP after a change from Cl− to an anion of lower permeability, or vice versa, is considerably slower than that expected if Cl− permeability of nerve terminals is similar to that of skeletal muscle fibres, and if the nerve terminal behaves as a single compartment. In frog cutaneous pectoris, transient changes in FMEPP produced by substitution of anions in the bathing solution were similar to those produced in mouse diaphragm, but more rapid in time course.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583474
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Correlation of O2 uptake rate and mitochondrial activity in carrot cell cultures exposed to laminar fluid shear (2000)
    Springer
    Biotechnology letters 22 (2000), S. 1919-1924 
    Details
    ISSN: 1573-6776
    Keywords: laminar fluid shear ; oxygen uptake rate ; plant culture ; sub-lytic cellular response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Measuring uncoupled oxygen uptake rate (OUR) could provide a convenient method for quantifying changes in the metabolic activity of plant cultures caused by hydrodynamic shear. Experiments on Daucus carota (carrot) cells were performed in a novel O2-permeable Couette viscometer at varying levels of laminar shear (6 to 100 N m−2). When the uncoupled OUR of the cells was compared with mitochondrial activity (determined by 2,3,5-triphenyl tetrazolium chloride assay), a significant correlation was observed (R=0.91 by linear regression).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026752418909
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...