tailieunhanh - Báo cáo y học: "Carbon monoxide affects electrical and contractile activity of rat myocardium"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Carbon monoxide affects electrical and contractile activity of rat myocardium | JOURNAL OF BIOMEDICAL SCIENCE Abramochkin et al. Journal of Biomedical Science 2011 18 40 http content 18 1 40 NSC The cost of publication in Journal of Biomedical Science Is borne by the National Science Council Taiwan RESEARCH Open Access Carbon monoxide affects electrical and contractile activity of rat myocardium 1 2 1 3 2 Denis V Abramochkin Nail N Haertdinov Maria V Porokhnya Andrew L Zefirov and Gusel F Sitdikova Abstract Background Carbon monoxide CO is a toxic gas which also acts in the organism as a neurotransmitter. It is generated as a by-product of heme breakdown catalyzed by heme oxygenase. We have investigated changes in electrical and contractile activity of isolated rat atrial and ventricular myocardium preparations under the influence of CO. Methods Standard microelectrode technique was used for intracellular registration of electrical activity in isolated preparations of atrial and ventricular myocardium. Contractions of atrial myocardial stripes were registered via force transducer. Results CO 10-4 - 10-3 M caused prominent decrease of action potential duration APD in working atrial myocardium as well as significant acceleration of sinus rhythm. In addition CO reduced force of contractions and other parameters of contractile activity. Inhibitor of heme oxygenase zinc protoporphyrin IX exerts opposite effects prolongation of action potential reduction of sinus rhythm rate and enhancement of contractile function. Therefore endogenous CO which may be generated in the heart due to the presence of active heme oxygenase is likely to exert the same effects as exogenous CO applied to the perfusing medium. In ventricular myocardium preparations exogenous CO also induced shortening of action potential while zinc protoporphyrin IX produced the opposite effect. Conclusions Thus endogenous or exogenous carbon monoxide may act as an important regulator of electrical and contractile cardiac activity. Background During the last twenty years .