CIRCADIAN-RHYTHMS; GENERAL-ANESTHETICS; LOCOMOTOR-ACTIVITY; RATS; KETAMINE

Pentobarbital, ketamine/xylazine and zoletil are the most commonly used agents for general anaesthesia in experimental studies using animal models. Table 1 summarizes the results of our chronobiological studies investigating the impact of anaesthesia on cardiac electrophysiology in rats. The results clearly show differences among three types of anaesthetics and their effects on the circadian rhythmicity of myocardial electrophysiological parameters in an in vivo rat model, presented in our studies as ?light-dark differences?. Although studies from other groups (Ohno et al. 2009, Mihara et al. 2012) have reported moderate or, alternatively, no effects of pentobarbital on the circadian rhythm of locomotor activity and the secretion of specific hormones in mice and rats, the disruptive effect of pentobarbital on circadian oscillations in electrophysiological parameters of the rat heart was evident in our study.