Antiarrhytmic effects of opioid receptor agonist dalargin and opioid receptor antagonist naloxone in the experimental model of cerebral fat embolism: topical issues of the experimental cardiology

Opioid peptides belong to the new actively studied class of the pharmacological agents showed to possess a stress-limiting and possibly cardioprotective effects modulating the activity of μ- and δ-opioid receptors. Thereby, studying the prospects for clinical application of opioid receptors is extremely important. Aim: to study the role of opioid receptors agonist dalargin and opioid receptor antagonist naloxone in heart rhythm disorders and in altered repolarization phase of the ventricles in the model of experimental cerebral fat embolism including hypothalamic damage in rabbits. A total of 48 chinchilla rabbits were used as experimental models for the rhythm disorders occurred as a complication of cerebral fat embolism; the antiarrhytmic and cardioprotective effects of opioid receptors (OR) agonists dalargin and opioid receptor antagonist naloxone were examined. Data showed that experimental cerebral fat embolism caused various types of arrhytmias with different morphology and severity, myocardial infarction-like ECG changes, and WPW-like ECG changes. Both classes of drugs increased survival of animals with cerebral fat embolism. Naloxone surpassed dalargin in reducing the frequency of ventricular fibrillation and WPW activity. Results of our research show that experimental cerebral fat embolism is associated with hypothalamus damage and high risk of development of fatal arrhythmias. Administration of opioid receptors agonist dalargin or opioid receptors antagonist naloxone provided the stress-limiting, antiarrhytmic, and probably cardioprotective effects, significantly improving survival of animals.