title: Electrophysiological studies of upregulated P2X7 receptors in rat superior cervical ganglia after myocardial ischemic injury.
abstract: Myocardial ischemic injury activates cardiac sympathetic afferent fibers and elicits a sympathoexcitatory reflex by exciting sympathetic efferent action, with resultant augmentation of myocardial oxygen consumption, leading to a vicious cycle of exaggerating myocardial ischemia. P2X7 receptor participates in the neuronal functions and the neurological disorders. This study examined the role of P2X7 receptor of superior cervical ganglia (SCG) in sympathoexcitatory reflex. Our results showed that the expression of P2X7 receptor at both mRNA and protein in SCG was increased after myocardial ischemic injury. P2X7 receptor agonists at the same concentration activated much larger amplitudes of the currents in the SCG neurons of myocardial ischemic rats than those in control rats. P2X7 receptor antagonist (brilliant blue G, BBG) significantly inhibited P2X7 receptor agonist-activated currents in the SCG neurons. Excessive phosphorylation of MAPK ERK1/2 upon the activation of P2X7 receptor might be a mechanism mediating the signal transduction after myocardial ischemic injury. Therefore, the sensitized P2X7 receptor in SCG was involved in the nociceptive transmission of sympathoexcitatory reflex induced by myocardial ischemic injury.
authors.affiliation: Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China.
authors.forename: Fanjun
authors.initials: F
authors.lastname: Kong
authors.forename: Shuangmei
authors.initials: S
authors.lastname: Liu
authors.forename: Changshui
authors.initials: C
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Guodong
authors.initials: G
authors.lastname: Li
authors.forename: Guilin
authors.initials: G
authors.lastname: Li
authors.forename: Yun
authors.initials: Y
authors.lastname: Gao
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.forename: Guihua
authors.initials: G
authors.lastname: Tu
authors.forename: Haiying
authors.initials: H
authors.lastname: Peng
authors.forename: Shuyi
authors.initials: S
authors.lastname: Qiu
authors.forename: Bo
authors.initials: B
authors.lastname: Fan
authors.forename: Qicheng
authors.initials: Q
authors.lastname: Zhu
authors.forename: Shicheng
authors.initials: S
authors.lastname: Yu
authors.forename: Chaoran
authors.initials: C
authors.lastname: Zheng
authors.forename: Shangdong
authors.initials: S
authors.lastname: Liang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D020935:MAP Kinase Signaling System; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism / Q000502:physiology*; D017783:Superior Cervical Ganglion / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D058486:Receptors, Purinergic P2X7
keywords: Myocardial ischemia; P2X(7) receptor; Superior cervical ganglion; Whole cell patch clamp technique