Pavol Svorc

Pavol Jozef Šafárik University in Košice · Department of Medical Physiology

Experiments should always be based on control values. This assumption fully applies to cardiovascular parameters, such as heart rate (HR) and blood pressure (BP), which are highly sensitive to various external and internal stimuli and can already be significantly altered when an experiment begins. Therefore, it is neces sary to determine which v...

In patients with obstructive sleep apnea (OSA) during obstructive events, episodes of hypoxia and hypercapnia may modulate the autonomic nervous system (ANS) by increasing sympathetic tone and irritability, which contributes to sympathovagal imbalance and ultimately dysautonomia. Because OSA can alter ANS function through biochemical changes, we ca...

The aim was to evaluate the current state of the autonomic nervous system (ANS) activity under general anesthesia using heart rate variability (HRV) in dependence on the light-dark (LD) cycle in healthy, sexually mature, spontaneously breathing, zoletil-anesthetized (30 mg/kg) Wistar rats of both sexes after a 4-week adaptation to an LD cycle (12 h...

General anesthesia is an established and well-known factor with a significant impact on cardiac parameters, which can be a problem in the final evaluation of changes in the individual electrophysiological myocardial parameters after various interventions. The present chapter provides a composite review of published data on electrocardiographic para...

In in vivo cardiovascular or toxicological studies involving rat models, changes in selected electrocardiographic (ECG) parameters are monitored after various interventions to assess the origin and development of heart rhythm disorders. Each ECG parameter has diagnostic significance; as such, commonly evaluated ECG parameters, including heart rate,...

Background: It is known that general anesthesia weakens autonomic function and baroreflex control. Intravenous anesthetics may have different qualitative and quantitative effects on the peripheral autonomic nervous system (ANS) and, can thus, alter the activity of sympathetic or parasympathetic divisions of the ANS. Presently, there are relatively...

Introduction: The primary objective of this study was to determine the impact of spectral powers of heart rate variability (HRV) on changes in heart rate (HR), total spectral power of HRV, and low-frequency (LF)/high-frequncy (HF) ratio in healthy, sexually mature rats of both sexes spontaneously breathing under zoletil anesthesia in the light (i...

Objectives: It is known that general anesthesia weakens autonomic function and baroreflex control. Intravenous anesthetics may have different qualitative and quantitative effects on the peripheral autonomic nervous system (ANS) and, can thus, alter the activity of sympathetic or parasympathetic divisions of the ANS. Presently, there are relatively...

Background: It is known that general anesthesia weakens autonomic function and baroreflex control. Intravenous anesthetics may have different qualitative and quantitative effects on the peripheral autonomic nervous system (ANS) and, can thus, alter the activity of sympathetic or parasympathetic divisions of the ANS. Presently, there are relatively...

The aim was to evaluate the current state of the autonomic nervous system (ANS) activity under general anesthesia using heart rate variability (HRV) in dependence on the light-dark (LD) cycle in healthy, sexually mature, spontaneously breathing, zoletil-anesthetized (30 mg/kg) Wistar rats of both sexes after a 4-week adaptation to an LD cycle (12 h...

The role of the Autonomic Nervous System (ANS) and its organ-specific functions are largely elucidated. Heart Rate Variability (HRV) analysis is a popular tool for the assessment of autonomic cardiac control. Heart rate and its changes are a sensitive indicator of ANS function, therefore cardiovascular autonomic regulation is considered to be the m...

Background: It is known that general anesthesia weakens autonomic function and baroreflex control. Intravenous anesthetics may have different qualitative and quantitative effects on the peripheral autonomic nervous system (ANS) and, can thus, alter the activity of sympathetic or parasympathetic divisions of the ANS. Presently, there are relatively...

Although it is generally assumed that females are not significantly more variable than males, there are studies that have demonstrated that differences may be quite large. The aim of the present in vivo study was to determine the effect of general anaesthesia on the status of acid–base balance in spontaneously breathing rats of both sexes in depend...

The aim of study was to review the status of arterial pH, pO2 and pCO2 under general anesthesias in dependence on the light-dark (LD) cycle in spontaneously breathing rats. The experiments were performed using three- to four-month-old pentobarbital(P)-, ketamine/xylazine(K/X)- and zoletil(Z)-anesthetized female Wistar rats after a four-week adaptat...

The aim of study was to review the status of arterial pH, pO2 and pCO2 under general anesthesias in dependence on the light-dark (LD) cycle in spontaneously breathing rats. The experiments were performed using three- to four-month-old pentobarbital(P)-, ketamine/xylazine(K/X)- and zoletil(Z)-anesthetized female Wistar rats after a four-week ad...

This investigation aimed to review the initial state of electrophysiological parameters that may predict the development of heart rhythm disorders in spontaneously-breathing pentobarbital-, ketamine-xylazine- and zoletil-anesthetized rats. These data will contribute to building a wider framework for a chronobiological perspective on the dependence...

The specific aim of the present study, with respect to dependence on the light–dark (LD) cycle under in vivo conditions in spontaneously breathing rats was to review initial state in electrophysiological parameters that may predict the development of heart rhythm disorders in pentobarbital (40 mg/kg), ketamine–xylazine (100 + 15 mg/kg) and zoletil...

Crohn's disease and ulcerative colitis, known together as inflammatory bowel diseases (IBDs), and celiac disease are the most common disorders affecting not only adults but also children. Both IBDs and celiac disease are associated with oxidative stress, which may play a significant role in their etiologies. Reactive oxygen species (ROS) such as su...

The design and development of experimental, in vivo chronobiological animal models may help reveal some of the relationships between circadian rhythms and biological function, which can be very difficult to study in humans. To perform ethically acceptable cardiovascular research involving animals, the use of general anaesthesia is often necessary....

Zoletil anaesthesia does not affect vital functions; however, there is no literature evidence regarding the effect of zoletil anaesthesia on the circadian rhythm(s) of vital functions. The aims of this study, with respect to dependence on the light-dark (LD) cycle under in vivo conditions in spontaneously breathing zoletil-anaesthetized rats, were...

Administration of anaesthesia may influence specific aspects of in vivo animal experiments and is an especially important consideration for experiments conducted during the daytime. Although chronobiological studies investigating interactions between general anaesthesia and circadian rhythms are sparse, all suggest that general anaesthetic agents h...

Administration of anaesthesia during the daytime is important and may influence specific aspects of in vivo animal experiments. The aim of the present study was to refer to the suitability of the use of ketamine/xylazine anaesthesia in chronobiological studies. Study was performed in ketamine-/xylazine-anaesthetized female Wistar rats (100 mg/kg/15...

Basis: Restless legs syndrome (RLS) is a neurological disorder characterized by throbbing, pulling, creeping, or other unpleasant sensations in the legs and an uncontrollable, and sometimes overwhelming urge to move them. Symptoms occur primarily at night, when a person is relaxing or at rest and can increase in severity during the night. Moving th...

Reoxygenation following hypoxic episodes can increase the risk for the development of ventricular arrhythmias, which, in addition to circadian aspects of reoxygenation arrhythmias has not been studied extensively. The aim of the present study was to evaluate circadian changes in the electrical stability of the rat heart during reoxygenation followi...

Pavol Svorc,1,2 Alexander Marossy,1 Pavol Svorc Jr2 1Department of Physiology, Medical Faculty, Safarik University, Kosice, Slovak Republic; 2Department of Physiology, Medical Faculty, Ostrava University, Ostrava, Czech Republic Objective: Respiratory alkalosis is an extremely common and complicated problem affecting virtually every organ system wh...

The aim of the present study was to determine the effect of ketamine/ xylazine and pentobarbital anaesthesia on heart rate variability as a marker of autonomic nervous system activity. The experiments were performed in ketamine/ xylazine (10 mg/kg/15 mg/kg) and pentobarbital (40 mg/kg, i.p.) anaesthetized female Wistar rats, after adaptation to a l...

Referát 37 PETER PATLEVIČ a , FRANTIŠEK DORKO a,c , PAVOL ŠVORC JR. b , JANKA VAŠKOVÁ d a LADISLAV VAŠKO d a Ústav anatomie, b Ústav fyziologie, Lékařská fakulta, Ostravská univerzita v Ostravě, Syllabova 19, 703 00 Ostrava – Zábřeh, c Ústav anatómie, Lekárska Fakulta, Univerzita Pavla Jozefa Šafárika v Košiciach, Šrobárová 2, 040 80 Košice, d Ústa...

Primary objective: Studies focusing on the relationship between acid–base balance in vivo in rats and the dependence on the light–dark (LD) cycle are lacking. Research design: The aim of the study was on the chronobiological aspects of the impact of artificial ventilation on pH and blood gases in vivo in rats. Methods and procedures: The experiment...

Generally, it is assumed that heart-rhythm disorders during hypoxia result from the interplay between the autonomic nervous system (ANS) and the direct effect of hypoxia on cardiorespiratory structures of the central nervous system and on the myocardium. Circadian variability in the ANS may substantially influence the electrical stability of the my...

Man is exposed to the periodical processes of external environment practically with the synchronization of all his functions during the entire lifespan. The circadian rhythms (24 hour rhythms) are studied most frequently and they are demonstrated also in haematology. Detailed understanding of the circadian timing in fluctuation of some haematologic...

The aim of this study was to evaluate the effect of ventilation on electrocardiographic time intervals as a function of the light-dark (LD) cycle in an in vivo rat model. RR, PQ, QT and QTc intervals were measured in female Wistar rats anaesthetized with both ketamine and xylazine (100 mg/15 mg/kg, i.m., open chest experiments) after adaptation to...

Background / Purpose: It is supposed that both the hypoxic changes in the phasic and tonic drive of the autonomic nervous system and the alterations in the sensitivity of the myocardium to the autonomic nervous drive maybe involved in the effect of preconditioning.This chronophysiological study was designed to examine the effect of a light-dark c...

The aim of this study was to evaluate the effect of ventilation on electrocardiographic time intervals as a function of the light-dark (LD) cycle in an in vivo rat model. RR, PQ, QT and QTc intervals were measured in female Wistar rats anaesthetized with both ketamine and xylazine (100 mg/15 mg/kg, i.m., open chest experiments) after adaptation to...

The human, as well as most animal species on our planet, is exposed to regular periodical changes of the external enviroment, reflected in parallel changes in the physiological functions. In the present time, it is known that all cardiovascular functions show circadian dependence, not only blood pressure and heart rate, but also in electrophysiolog...

The aim of the study was to evaluate the effect of ventilatory manoeuvres on some ECG parameters as a function of the light-dark (LD) cycle in in vivo conditions. The PQ and QT intervals were measured in ketamine/xylazine-anaesthetized female Wistar rats (100 mg/15 mg/kg, i.m.) after adaptation to an LD cycle (12:12 h). The animals were exposed to...

The main functions of the blood are the transport, and delivery of oxygen and nutrients, removal of carbon dioxide and waste products of metabolism, distribution of heat and signals of immune system. They are provided by circulation due to the driving force of the heart. Circulation of the blood depends on its rheological properties of the blood as...

Cardioprotective effects by hypoxic preconditioning are well known mainly through in vitro experiments. However, the chronobiological aspects of phenomenon of cardioprotection by hypoxic preconditioning have not been studied in in vitro and in vivo experiments, and there are no consistent data regarding the daytime dependence of preconditioning eff...

In present time, to classify the healthy as potencional possibility of the organism to accept variable environment influences without the break of the biological important functions is not satisfactory. Examples from the different field of the clinical medicine refer to importance of the knowledge's of the circadian rhythmicity concerning many dise...

The aim of the study was to determine the dependence of changes in the electrical stability of the heart on the light-dark cycle (LD cycle) in disorders of pulmonary ventilation. The ventricular arrhythmia threshold (VAT) was measured in female Wistar rats (adaptation to the light regime 12:12 h, ketamine/xylazine anesthesia 100 mg/15 mg/kg, i.m.,...

To determine the effect of the light-dark cycle (LD) and type of anesthetic agent used on changes in the electrical stability of the heart in disorders of pulmonary ventilation. The ventricular arrhythmia threshold (VAT) and heart rate (HR) were measured in anesthetized female Wistar rats adapted to an LD regimen of 12 h:12 h (pentobarbital sodium...

Erythrocyte microrheology changes were measured by cation-osmotic haemolysis in Wistar albino rats of both sexes. Erythrocyte membrane biophysical properties were estimated using the method of cation-osmotic haemolysis (COH) described by Nicak and Mojzis [Comp. Haematol. Int. 2 (1992), 84-86]. COH in male rats was higher in low ionic strength mediu...

 Twenty-two healthy young male volunteers, between 15 and 19 years of age, took part in this study. They were subjected to a series of exercises on a veloergometer loaded at two submaximal levels of 1.5 W/kg and 2.0 W/kg, both at 60 steps/min for 4 min, and one maximal level, which commenced at 3.0 W/kg at 70 steps/min and increased every minute by...

The aim of our study was to compare the effect of two anaesthetic agents pentobarbital and ketamine/xylazine on the ventricular arrhythmia threshold (VAT) and the heart rate (HR) in the rat hypoventilation-reoxygenation model. Open chest experiments were performed under general anaesthesia in female Wistar rats (310 ± 15 g, adapted to a light - dar...

Hypoventilation, as one of ventilatory disorders, decreases the electrical stability of the heart similarly as ischemia. If preconditioning by short cycles of ischemia has a cardioprotective effect against harmful influences of a prolonged ischemic period, then preconditioning by hypoventilation (HPC) can also have a similar effect. Anesthetized ra...

Ischaemic disease is one of the grave states injuring the myocardium and resulting in not only disorders of the electrophysiological properties of the heart, but also in those mechanical contractile. Therefore the various forms of cardioprotection become very important in the myocardial protection against irreversible injury resulting in dangerous...

It is a known fact that there is a relationship between some ventilatory disorders and the incidence of ventricular arrhythmias. The aim of our study was to show this relation in the circadian dependence in in-vivo rat models. The electrical stability of the heart was measured by ventricular arrhythmia threshold (VAT) at 3h intervals during a 24h p...

The gastrointestinal system is the gate through which nutritive substances, vitamins, minerals, and fluids enter the body. Proteins, fats and complex carbohydrates are broken down into absorbable units (products of the digestion) in the digestive tract and finally they are absorbed together with vitamins, minerals and water into the blood or the ly...

Hypoxia, similarly as myocardial ischemia, decreases the electric stability of the heart and thus produces the conditions for the genesis of ventricular arrhythmias within the 24 h period however a prompt restoration of oxygen supply or blood flow within myocardium causes serious ventricular arrhythmias. Therefore the aim of our study was to evalua...

The aim of our study was to verify the relationship between heart rate (HR) and ventricular fibrillation threshold (VFT) during different types of ventilation in female Wistar rats from the circadian point of view. The experiments were performed under pentobarbital anesthesia (40 mg/kg i.p., adaptation to a light-dark cycle 12:12 h, open chest expe...

A 24h rhythm of the ventricular fibrillation threshold (VFT) was investigated in female Wistar rats under conditions of normal ventilation (NV) (17 animals) and hypoventilation (HV) (10 animals). The animals were adapted to a daily 12:12h light-dark cycle with the dark period from 18:00 to 06:00 under constant temperature conditions. The experiment...

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 w...