[Network correlation of circRNA-miRNA and the possible regulatory mechanism in acute myocardial infarction]

Objective: Using microarray technology, to research characteristic circRNA and miRNA expression profile of acute myocardial infarction (AMI), and then explore the role of these circRNA and miRNA in gene regulation. The aim is to explore the mechanism of development of AMI. Methods: The patients hospitalized in the Cardiovascular Research Center of the First Affiliated Hospital of Xinxiang Medical University between November 2016 and January 2017 were included and divided into control group and AMI group according to diagnostic criteria. We collected their whole blood and extracted the total RNA, and the expression profiles of circRNA and microRNA genes in peripheral blood of AMI were analyzed by gene chip. We predicted circRNA which was possible to combine with miRNA, and drew a network diagram, and the differentially expressed circRNA was analyzed by GO and Pathway. Results: There was difference in circRNA expression profile between the control group and the AMI group. The results showed: (1) a total of 1 670 circRNA had differential expressions, and in the analysis of miRNA expression, 13 miRNA had differential expressions (P<0.05, fc≥2); (2) multiple circRNAs-miRNAs were involved in the occurrence of AMI; (3) the analysis of GO and Pathway for differentially expressed circRNAs showed that many pathways, disease and function participated in it. Conclusion: CircRNA, as an important post transcriptional regulator, is closely related to the development of AMI with miRNA.

[Effects of neferine on heart electromechanical activity in anaesthetized cats]

Neferine, an alkaloid extracted from the green seed embryo of Nelumbo nucifera Gaertn, has been shown to have anti-arrhythmic action. Neferine 1-10 mg/kg iv dose-dependently decreased the monophasic action potential amplitude (MAPA), prolonged the monophasic action potential duration (MAPD). It also decreased LVP, dP/dt, prolonged SCL, and reduced arterial blood pressure in a dose-dependent manner. These effects were similar to those of quinidine, and different from tetrandrine. The latter had an inhibitory effect on LVP and dP/dt, but had no influence on MAPA and MAPD. The results indicate that neferine and quinidine have similar effects on heart electro-mechanical activity.

[Effects of neferine on transmembrane potentials of guinea pig myocardium]

Neferine, an alkaloid first isolated from the seed embryo of Nelumbo nucifera Gaertn in China, possesses an anti-arrhythmic action. The effects on the action potential duration (APD) and the maximal upstroke velocity (Vmax) in different driving rates, the slow response action potentials of K+-depolarized ventricular myocardium and the ouabain-induced oscillatory potentials were studied in guinea pig papillary muscles. Neferine 10 and 50 mumols/L markedly suppressed the transmembrane potentials Vmax at 0.1-5 Hz. It (50 mumols/L) prolonged the APD at 0.5-5 Hz. Neferine 10-100 mumols/L inhibited the contractility, amplitude of action potentials and Vmax of K+-depolarized guinea pig papillary muscles in a concentration-dependent manner, and 100 mumols/L decreased the amplitude of action potentials and Vmax from 73 +/- 7 mV and 6.0 +/- 1.7 V/s of control to 57 +/- 4 mV and 3.2 +/- 0.7 V/s, respectively. In addition, neferine 50 mumols/L abolished the oscillatory potentials induced by ouabain. The results indicate that the effects of neferine on APD and Vmax seem not to be related to the frequency of stimuli, and its anti-arrhythmic action is relevant to the inhibitory effects on Na+, K+, Ca2+ currents of myocardium.