Norepinephrine release from sympathetic nerves in mammalian hearts in vivo measured by c PEC(cardiac Physiology of Electro Chemistry)

【摘要】：Sympathetic nerve in heart is essential in heart physiology and diseases,because sympathetic nerve release catecholamines to regulate cardiac cells including ventricular myocytes and atrial myocytes and vascular cells through GPCR receptors.By using micro carbon fiber electrode(CFE),we recorded catecholamine release from the sympathetic nerve terminals in rabbit and rat hearts,by a novel method termed cardiac in-vivo Physiology of Electro Chemistry(c PEC).CPEC offers real-time recording of norepinephrine(NE)release from sympathetic nerves in mammalian hearts in vivo.We found that(1)membrane depolarization induced a c PEC signal current at 780 m V but not 0 m V;(2)as examined by microdialysis based HPLC,c PEC signal is oxidization current of DHPG(a NE metabolic substance),implicating that sympathetic NE release is responsible for c PEC;(3)Hypoxia enhanced the c PEC signals induced by electrical stimulation of stellate ganglion.(4)The c PEC signals decreased markedly when the vagus nerve was pre-challenged by electrical stimulation.(5)ischemia-reperfusion evoked a rapid c PEC/sympathetic NE release in rabbit heart in vivo.Together,NE release of c PEC signal under physiology and pathological(hypoxia)conditions provide unprecedented spatiotemporal resolutions to investigate mechanisms for heart rhythm by NE nerve regulations.