Circadian rhythm of the ventricular fibrillation threshold in female wistar rats

Title:

Circadian rhythm of the ventricular fibrillation threshold in female wistar rats

Creator:

Švorc, P., Wilk, P., Murár, J., Podlubný, I., Kujaník, Š., Bračoková, I., and Murín, M.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:7d9bfe57-f5e0-4f84-8193-d7674e63cfac
uuid:7d9bfe57-f5e0-4f84-8193-d7674e63cfac

Subject:

circadian rhythm, ventricular fibrillation threshold, and rat

Type:

article, model:article, and TEXT

Description:

The circadian rhythm of ventricular fibrillation threshold (VFT) and its relation to the heart rate (HR) and the rectal temperature (RT) was studied in female Wistar rats. The animals were exposed to daily light-dark cycles of 12 h of light alternating with 12 h of darkness and were under pentobarbital anaesthesia (40 mg/kg i.p.). The experiments were performed on open chest animals and VFT was measured by direct stimulation of the myocardium. VFT in female rats showed a circadian rhythm with the acrophase -338° (at 22.53 h), with the mesor 2.58 mA and the amplitude 0.33 mA. HR was not significantly changed during the experiments and no dependence was found between VFT and HR during the whole 24-hour period (r=0.08). The acrophase of the circadian rhythm of HR (on -47°, i.e. at 03.08 h) was shifted to the acrophase of VFT. The circadian rhythms of RT before the application of the anaesthetic agent and under general anaesthesia before the operative interventions had a very similar course with the nearly corresponding acrophoses as the circadian rhythm of VFT. It is concluded that the electrical stability of the rat heart measured by VFT shows the significant circadian rhythm in a parallel with the circadian rhythm of RT and probably without dependence on the changes of HR.

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 1994 Volume:43 | Number:6

Harvested from:

CDK

Metadata only:

false