Increased susceptibility of aged rats to low K+-induced ventricular fibrillation

2002 ◽  
Vol 34 (6) ◽  
pp. A85
Author(s):  
Vladimír Knezl ◽  
Narcis Tribulová ◽  
L'udmila Okruhlicová ◽  
Ján Slezák ◽  
Ján Styk ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Aged Rats ◽  
Low K ◽  
Increased Susceptibility

Ventricular Excitability and Refractoriness in the Hypothermic Dog

1957 ◽  
Vol 189 (3) ◽  
pp. 591-595 ◽  
Author(s):  
E. T. Angelakos ◽  
E. G. Laforet ◽  
A. H. Hegnauer
Keyword(s):  
Heart Rate ◽  
Ventricular Fibrillation ◽  
Response Latency ◽  
Refractory Period ◽  
Cardiac Cycle ◽  
Significant Alteration ◽  
Entire Cardiac Cycle ◽  
Refractory Periods ◽  
Rate Of Recovery ◽  
Increased Susceptibility

Measurements of ventricular exctiability through the entire cardiac cycle of the dog under progressive hypothermia show that the ventricular refractory period (measured as absolute, total or functional refractory period) is greatly prolonged. This effect is not secondary to the changes in heart rate since normothermic animals with surgical A-V block having heart rates similar to those obtained under hypothermia do not show any great prolongation in the ventricular refractory period. At heart temperatures ranging from 38° to 23°C there is no significant alteration in the diastolic excitability of the ventricle. The rate of recovery of diastolic excitability and the response latency were greatly prolonged as reflected in the marked increase in the duration of the relative and functional refractory periods. It is suggested that the increased susceptibility of the hypothermic myocardium to ventricular fibrillation may be related to the observed changes in the rate of recovery of excitability.

scholarly journals Increased Susceptibility of the Heart to Ventricular Fibrillation During Metabolic Acidosis

1966 ◽  
Vol 19 (1) ◽  
pp. 63-70 ◽  
Author(s):  
PAUL H. GERST ◽  
WILLIAM H. FLEMING ◽  
JAMES R. MALM
Keyword(s):  
Metabolic Acidosis ◽  
Ventricular Fibrillation ◽  
Increased Susceptibility

scholarly journals PL - 034 Impact of PM2.5 Exposures and Pre-exercise on Pulmonary Function and Leukocyte Count in Aged Rats

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Fei Qin ◽  
Jiexiu Zhao ◽  
Mingxiao Xu ◽  
Yanan Dong ◽  
Zhongwei Wang
Keyword(s):  
Pulmonary Function ◽  
Health Effects ◽  
Whole Body ◽  
Aged Rats ◽  
Ambient Particles ◽  
Beneficial Effects ◽  
Adverse Health Effects ◽  
Adverse Health ◽  
Male Wistar Rats ◽  
Increased Susceptibility

Objective Exposure of PM2.5 has been associated with adverse respiratory and the risk of inflammation. While regular physical activity (PA) reduces the risk of many adverse health effects. This study aimed to examine the protection of pre-exercise on adverse health effects of Pulmonary Function and inflammatory induced by PM2.5 exposures in aged rats. Methods 24 male wistar rats, aged 16 months, were randomly divided into 4 groups: Sedentary (S), Exercise (E), Sedentary+ PM2.5 exposures (S+PM), and Exercise+ PM2.5 exposures (E+PM). The rats in all E-related groups went through an aerobic treadmill exercise protocol (15m/min, 30 min) at every other day. The PM-related groups of aged rats were exposed to concentrated ambient particles of less than 2.5 μm (PM2.5) or filtered air (FA) in Beijing, for 4 hours per day, 7 days per week for a total of 2 weeks. After 2-week PM Exposure, blood was taken to measure the count of white blood cell (WC), neutrophil (NE), lymphocytes (LY), monocyte (MO), eosinophils (EO) and basophil (BA), and pulmonary function examined by whole body plethysmography. Results After 2-week PM exposure, compared with E group, S+PM group’ s percentage of NE decreased significantly (p＜0.05), while the decline of NE% in E+PM group was small. Meanwhile, the obviously rise of BA% occurred in S+PM and E+PM group compared with sedentary group (p＜0.05). 2) Compared with E group, the Index of constriction (Penh and PAU) were increased evidently in S+PM group after PM exposure (p＜0.05), while the value of Penh were significantly improved in E+PM group (p＜0.05). 3) Compared with E group, the rejection index (RinX) (p＜0.01) and duration of pause before inspiration (TP) (p＜0.05) were appeared a clearly inclined in S+PM group, as well as several up-regulated of RinX and TP showed in E+PM group. Conclusions 2-week PM2.5 exposures led to an increased susceptibility of infections, index of constriction and susceptibility of pulmonary function in aged rats. Moderate pre-exercise has beneficial effects on pulmonary function and immune function.

Effect of thyroxine (T4) on incidence of low K+-induced ventricular fibrillation (VF) and its conversion to sinus rhythm (S-R)

2002 ◽  
Vol 34 (6) ◽  
pp. A92
Author(s):  
Narcis Tribulová ◽  
Vladimír Knezl ◽  
L'udmila Okruhlicová ◽  
Ján Slezák ◽  
Ján Styk ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Sinus Rhythm ◽  
Low K

Transmembrane fluxes in ventricular fibrillation

1961 ◽  
Vol 200 (1) ◽  
pp. 122-124 ◽  
Author(s):  
Arthur H. Briggs ◽  
William C. Holland
Keyword(s):  
Atrial Fibrillation ◽  
Ventricular Fibrillation ◽  
Basic Mechanism ◽  
Critical Value ◽  
Flux Measurements ◽  
Low K

Transmembrane fluxes of K and the rate of net entry of Na were determined in isolated perfused rabbit hearts before and during ventricular fibrillation. These results were compared to previous flux measurements in atrial fibrillation. Control ventricles in low (K)0 media lost K at a rate of 8 pmoles cm–2sec–1. This was 2 1/2 times greater than the rate of K loss in control atria. The initiation of both atrial and ventricular fibrillation was associated with an increased K efflux, decreased K influx and marked increase of Na influx. The data were interpreted to suggest that both atrial and ventricular fibrillation are initiated by the same basic mechanism; that is an increase in Na entry above a critical value (K leaving the tissue in exchange). This critical value can be easily attained in perfused ventricles by lowering the (K)0.

scholarly journals Age and Heat Exposure-Dependent Changes in Antioxidant Enzymes Activities in Rat's Liver and Brain Mitochondria: Role of α-tocopherol

2013 ◽  
pp. 503-510 ◽  
Author(s):  
V. STOJKOVSKI ◽  
N. HADZI-PETRUSHEV ◽  
V. ILIESKI ◽  
R. SOPI ◽  
I. GJORGOSKI ◽  
...  
Keyword(s):  
Reactive Oxygen Species Production ◽  
Heat Exposure ◽  
Brain Mitochondria ◽  
Antioxidant Enzyme Activities ◽  
Oxygen Species ◽  
Aged Rats ◽  
Antioxidant Enzymes Activities ◽  
Species Production ◽  
Increased Susceptibility

To investigate the role of mitochondrial antioxidant capacity during increased susceptibility to heat accompanied by the aging, young and aged Wistar rats were exposed on heat for 60 min. After heat exposure, hepatic and brain mitochondria were isolated. Our results revealed changes in antioxidant enzyme activities in liver and brain mitochondria from young and to a greater extent in aged rats. Our measurements of MnSOD, GPx and GR activity indicate greater reactive oxygen species production from the mitochondria of aged heat exposed in comparison to young heat exposed rats. Also in the aged rats, the effect of α-tocopherol treatment in the prevention of oxidative stress occurred as a result of heat exposure, is less pronounced. Taken together, our data suggest that mitochondria in aged rats are more vulnerable and less able to prevent oxidative changes that occur in response to acute heat exposure.

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