An Amperometric Study Of Catecholamine Release From Rabbit Hearts In Vivo

Background:Activation of cardiac sympathetic nerve plays an important role in pathophysiological progress of cardiovascular diseases.Common technologies detecting release of sympathetic transmitters,including microdialysis,isotope dilution methodology and so on, can't detect real-time cardiac release of NE.Amperometry is a electrochemical technology,which causes little damage to tissue and has high time and spatial resolutions.We designed a technology applying to in vivo cardiac recording, and recorded NE release in rabbit hearts using amperometry with the new technology.Object:To establish a new technology to in vivo record sympathetic NE release in hearts with amperometry by improving the original CFE manufacture,and to investigate NE release signals induced by hypoxia or sympathetic stimulations.Methods: 1.Exposing hearts by pericardial suspension and stabilizing hearts by a fixing device in vivo in adult rabbits.2.I,as well as LvJing and XiuYun,improved previous glass CFE to manufacture polyethylene fixing GFE and polypropylene floating GFE.Under tutor's instrcuctions,I constructed a new frame device to detect sympathetic NE release stably in an area of micrometers in heart ventricle,which induced by hypoxia or electrical stimulation.3.Establishing double-channel recording method to measure NE release simultaneously in both heart ventricles with floating GFEs. Results:1.In vitro test showed GFE can quantities NE release with good signal/noise ratio.2.CFE can detect heart sympathetic NE release induced by transient asphyxia with good reproducibility,and we found that cardiac NE release will decrease after repetitive asphyxias.3.GFE can record cardiac NE release induced by hypoxia or cervical sympathetic nerve(SG) and vagus nerve(VN) electrical stimulations with good reproducibility.4.Floating GFE can record NE oxidation signals induced by cervical SG and VN electrical stimulations.We found the signals are a kind of mixing signals of NE oxidation signals and electrocardiac signals.5.Floating GFEs can detect sympathetic NE release induced by cervical SG electrical stimulations simultaneously in left and right heart ventricles with double-channel recording device.Conclusion:Our study developed two recording technologies,fixing GFE and floating GFE,and both can record heart sympathetic NE release efficiently.Especially,floating GFE technology is simple,practical,have good reproducibility and do little damage to tissues,so it can be used to study cardiac sympathetic NE release signals in physical and pathological heart.With this innovative in vivo recording technology, for the fist time,I,together with LvJing and XiuYun, recorded real time induced cardiac NE release in rabbit ventricles in vivo.