Effects of palytoxin on the electrical activity of dog and rabbit heart

1977 ◽  
Vol 33 (11) ◽  
pp. 1487-1489 ◽  
Author(s):  
S. Weidmann
Keyword(s):  
Electrical Activity ◽  
Rabbit Heart

scholarly journals Exogenous connexin43-expressing autologous skeletal myoblasts ameliorate mechanical function and electrical activity of the rabbit heart after experimental infarction

2014 ◽  
Vol 96 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Ieva Antanavičiūtė ◽  
Eglė Ereminienė ◽  
Vaidas Vysockas ◽  
Mindaugas Račkauskas ◽  
Vilius Skipskis ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Skeletal Myoblasts

scholarly journals Antiarrhythmic Properties of Elsholtzia ciliata Essential Oil on Electrical Activity of the Isolated Rabbit Heart and Preferential Inhibition of Sodium Conductance

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 948
Author(s):  
Regina Mačianskienė ◽  
Lauryna Pudžiuvelytė ◽  
Jurga Bernatonienė ◽  
Mantė Almanaitytė ◽  
Antanas Navalinskas ◽  
...  
Keyword(s):  
Essential Oil ◽  
Electrical Activity ◽  
Rabbit Heart ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cardiac Electrical Activity ◽  
Surface Ecg ◽  
Elsholtzia Ciliata ◽  
Qrs Duration ◽  
Mapping Techniques

Elsholtzia ciliata essential oil (E. ciliata) has been developed in Lithuania and internationally patented as exerting antiarrhythmic properties. Here we demonstrate the pharmacological effects of this herbal preparation on cardiac electrical activity. We used cardiac surface ECG and a combination of microelectrode and optical mapping techniques to track the action potentials (APs) in the Langendorff-perfused rabbit heart model during atrial/endo-/epi-cardial pacing. Activation time, conduction velocity and AP duration (APD) maps were constructed. E. ciliata increased the QRS duration and shortened QT interval of ECG at concentrations of 0.01–0.1 μL/mL, whereas 0.3 μL/mL (0.03%) concentration resulted in marked strengthening of changes. In addition, the E. ciliata in a concentration dependent manner reduced the AP upstroke dV/dtmax and AP amplitude as well as APD. A marked attenuation of the AP dV/dtmax and a slowing spread of electrical signals suggest the impaired functioning of Na+-channels, and the effect was use-dependent. Importantly, all these changes were at least partially reversible. Our results indicate that E. ciliata modulates cardiac electrical activity preferentially inhibiting Na+ conductance, which may contribute to its effects as a natural antiarrhythmic medicine.

scholarly journals Effect of Carvacrol, TRP Channels Modulator, on Cardiac Electrical Activity

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Mantė Almanaitytė ◽  
Jonas Jurevičius ◽  
Regina Mačianskienė
Keyword(s):  
Electrical Activity ◽  
Trp Channels ◽  
Heart Function ◽  
Atrioventricular Node ◽  
Rabbit Heart ◽  
Inhibitory Effect ◽  
Resting Membrane Potential ◽  
Cardiac Electrical Activity ◽  
Epicardial Pacing ◽  
High Concentrations

Despite the wide application of carvacrol (CAR) in medicines, dietary supplements, and foods, there is still insufficient electrophysiological data on the mechanisms of action of CAR, particularly with regard to heart function. Therefore, in this study, we attempted to elucidate whether CAR, whose inhibitory effect on both cardiac and vascular TRPM7 and L-type Ca2+ currents has been demonstrated previously, could modify cardiac electrical activity. We used a combination of optical mapping and microelectrode techniques to track the action potentials (APs) and the spread of electrical activity in a Langendorff-perfused rabbit heart model during atrial/endo/epicardial pacing. Simultaneously, ECG recordings were acquired. Because human trials on CAR are still lacking, we tested the action of CAR on human ventricular preparations obtained from explanted hearts. Activation time (AT), AP duration (APD), and conduction velocity maps were constructed. We demonstrated that at a low concentration (10 μM) of CAR, only marginal changes in the AP parameters were observed. At higher concentrations (≥100 μM), a decrease in AP upstroke velocity (dV/dtmax), suggesting inhibition of Na+ current, and APD (at 50 and 90% repolarization) was detected; also slowing in the spread of electrical signals via the atrioventricular node was observed, suggesting impaired functioning of Ca2+ channels. In addition, a decrease in the T-wave amplitude was seen on the ECG, suggesting an impaired repolarization process. Nevertheless, those changes occurred without a significant impact on the resting membrane potential and were reversible. We suggest that CAR might play a role in modulating cardiac electrical activity at high concentrations.

scholarly journals Filament Dynamics during Simulated Ventricular Fibrillation in a High-Resolution Rabbit Heart

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Pras Pathmanathan ◽  
Richard A. Gray
Keyword(s):  
High Resolution ◽  
Ventricular Fibrillation ◽  
Electrical Activity ◽  
Three Dimensional ◽  
Coronary Vessels ◽  
Rabbit Heart ◽  
Filament Dynamics ◽  
Surface Patterns ◽  
Time Specific ◽  
Whole Heart

The mechanisms underlying ventricular fibrillation (VF) are not well understood. The electrical activity on the heart surface during VF has been recorded extensively in the experimental setting and in some cases clinically; however, correspondingtransmuralactivation patterns are prohibitively difficult to measure. In this paper, we use a high-resolution biventricular heart model to study three-dimensional electrical activity during fibrillation, focusing on the driving sources of VF: “filaments,” the organising centres of unstable reentrant scroll waves. We show, for the first time, specific 3D filamentdynamicsduring simulated VF in a whole heart geometry that includes fine-scale anatomical structures. Our results suggest that transmural activity is much more complex than what would be expected from surface observations alone. We present examples of complex intramural activity, including filament breakup and reattachment, anchoring to the thin right ventricular apex; rapid transitions among various filament shapes; and filament lengths much greater than wall thickness. We also present evidence for anatomy playing a major role in VF development and coronary vessels and trabeculae influencing filament dynamics. Overall, our results indicate that intramural activity during simulated VF is extraordinarily complex and suggest that further investigation of 3D filaments is necessary to fully comprehend recorded surface patterns.

Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

1995 ◽  
Vol 53 ◽  
pp. 972-973
Author(s):  
R H. Selinfreund ◽  
A. H. Cornell-Bell
Keyword(s):  
Membrane Potential ◽  
Confocal Microscopy ◽  
Patch Clamp ◽  
Electrical Activity ◽  
Time Lapse ◽  
Neuronal Firing ◽  
Neuronal Membrane ◽  
Pituitary Cells ◽  
Patch Clamp Recording ◽  
Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

Fate of sperm membrane in fertilized ova

1993 ◽  
Vol 51 ◽  
pp. 40-41
Author(s):  
Frank J. Longo
Keyword(s):  
Electron Microscopy ◽  
Electrical Activity ◽  
Sea Urchins ◽  
Morphological Changes ◽  
Integrated System ◽  
Electrophysiological Recording ◽  
Experimental Conditions ◽  
The Status ◽  
Sperm Membrane ◽  
Temporal And Spatial

Measurement of the egg's electrical activity, the fertilization potential or the activation current (in voltage clamped eggs), provides a means of detecting the earliest perceivable response of the egg to the fertilizing sperm. By using the electrical physiological record as a “real time” indicator of the instant of electrical continuity between the gametes, eggs can be inseminated with sperm at lower, more physiological densities, thereby assuring that only one sperm interacts with the egg. Integrating techniques of intracellular electrophysiological recording, video-imaging, and electron microscopy, we are able to identify the fertilizing sperm precisely and correlate the status of gamete organelles with the first indication (fertilization potential/activation current) of the egg's response to the attached sperm. Hence, this integrated system provides improved temporal and spatial resolution of morphological changes at the site of gamete interaction, under a variety of experimental conditions. Using these integrated techniques, we have investigated when sperm-egg plasma membrane fusion occurs in sea urchins with respect to the onset of the egg's change in electrical activity.

Fit Vs Faint: Assessing Work Causation in “Idiopathic Fall” Cases

2014 ◽  
Vol 19 (5) ◽  
pp. 3-12
Author(s):  
Lorne Direnfeld ◽  
David B. Torrey ◽  
Jim Black ◽  
LuAnn Haley ◽  
Christopher R. Brigham
Keyword(s):  
Blood Flow ◽  
Electrical Activity ◽  
Loss Of Consciousness ◽  
Brain Electrical Activity ◽  
Medical Terminology ◽  
Scientific Analysis ◽  
Medical Causation ◽  
The Individual ◽  
The Brain ◽  
Current Science

Abstract When an individual falls due to a nonwork-related episode of dizziness, hits their head and sustains injury, do workers’ compensation laws consider such injuries to be compensable? Bearing in mind that each state makes its own laws, the answer depends on what caused the loss of consciousness, and the second asks specifically what happened in the fall that caused the injury? The first question speaks to medical causation, which applies scientific analysis to determine the cause of the problem. The second question addresses legal causation: Under what factual circumstances are injuries of this type potentially covered under the law? Much nuance attends this analysis. The authors discuss idiopathic falls, which in this context means “unique to the individual” as opposed to “of unknown cause,” which is the familiar medical terminology. The article presents three detailed case studies that describe falls that had their genesis in episodes of loss of consciousness, followed by analyses by lawyer or judge authors who address the issue of compensability, including three scenarios from Arizona, California, and Pennsylvania. A medical (scientific) analysis must be thorough and must determine the facts regarding the fall and what occurred: Was the fall due to a fit (eg, a seizure with loss of consciousness attributable to anormal brain electrical activity) or a faint (eg, loss of consciousness attributable to a decrease in blood flow to the brain? The evaluator should be able to fully explain the basis for the conclusions, including references to current science.

Gastric electrical activity in normal neonates during the first year of life. Effect of lactation with breast milk and formula

2001 ◽  
Vol 120 (5) ◽  
pp. A209-A209
Author(s):  
G RIEZZO ◽  
R CASTELLANA ◽  
T DEBELLIS ◽  
F LAFORGIA ◽  
F INDRIO ◽  
...  
Keyword(s):  
Breast Milk ◽  
Electrical Activity ◽  
First Year ◽  
Gastric Electrical Activity ◽  
First Year Of Life ◽  
Normal Neonates
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