Search

The remarkably diverse effects of the catecholamines and similar sympathomimetic agents are directly related to an understanding of the classification and different types of adrenoreceptors. Characteristics and physiological regulatory mechanisms of the receptor result in variable response of organ systems to catecholamines stimulation. Different adrenoreceptors regulate distinct physiological processes by controlling the synthesis or release of a variety of second messengers. The goal of this review was to turn one's attention to the below mentioned aspects. There are three known subtypes of each alpha1-, alpha2- and beta-adrenoreceptor types. Structure of the adrenoreceptors, which belong to subtypes of the same receptor type, is similar and structure of the adrenoreceptors of the separate types is very different. Genetic peculiarities of the receptors may influence liability to some diseases. Acting on the adrenoreceptors may change function of many organs and may serve for the treatment of cardiovascular, respiratory tract diseases and allergic reactions. Selective acting on the adrenoreceptors of the separate subtypes may have the different effect on the organs. Great consideration is given for that property in the development of new drugs: substitution by different chemical radicals leads to increasing selectivity for the separate subtypes of the adrenoreceptors. The prolonged use of the adrenomimetics may lead to refractoriness.

Objective: To find out if radiofrequency ablation as method of treatment of cardiac arrhythmia influences platelet aggregation and if intensity of this process depends on the number of radiofrequency ablation episodes for one patient., Material and Methods: We analyzed platelet aggregation before, right after and in 24 hours after radiofrequency ablation in whole blood and platelet rich plasma in 39 cases with cardiac arrhythmias. Adenosine diphosphate and adrenaline were used for aggregation induction. Three groups of patients were formed based on the number of radiofrequency ablation episodes: A-- <10, B--10-20, C-- >20 for one patient., Results: We detected a decrease in spontaneous, adenosine diphosphate and adrenaline induced platelet aggregation in plasma right after radiofrequency ablation, and also the same tendency was noted in adenosine diphosphate induced aggregation in whole blood. In 24 hours after radiofrequency ablation platelet aggregation tended to return to pre-radiofrequency ablation levels. Based on the number of radiofrequency ablation episodes we detected significant changes in spontaneous and adrenaline-induced aggregation in plasma. In group A adrenaline induced aggregation after radiofrequency ablation increased by 0.4%, in group B it decreased by 15.7% and in group C it decreased by 19.4% from pre-radiofrequency ablation level (p<0.05, between groups A and C). Spontaneous platelet aggregation after radiofrequency ablation decreased in group A 41.9%, in group B--20.8% and in group C--18.4% from pre-radiofrequency ablation level (p<0.05 between groups A and C). The greater decrease in adenosine diphosphate induced aggregation in plasma and in whole blood was detected in the group with larger number of radiofrequency ablation episodes., Conclusions: This study found that platelet aggregation decreased in plasma and in whole blood after radiofrequency ablation. And this alteration was significant in groups B and C, when the number of radiofrequency ablation episodes were >10. In 24 hours platelet aggregation increased again to pre- radiofrequency ablation level.