Disinhibition of rostral raphe pallidus neurons increases cardiac sympathetic nerve activity and heart rate
Disinhibition of rostral raphe pallidus neurons increases cardiac sympathetic nerve activity and heart rate
复制标题
DOI：
10.1016/s0006-8993(03)02981-0
复制
发表时间：
2003-08-01
期刊：
影响因子：
2.9
通讯作者：
Morrison, SF
中科院分区：
文献类型：
--
作者：
Cao, WH;Morrison, SF
在乌拉坦-氯醛糖麻醉、人工呼吸的大鼠中缝背核(RPA)内微量注射GABA受体拮抗剂荷包牡丹碱，观察其对动脉压(AP)、心率(HR)和心脏交感神经活动(CSNA)的影响。在26只动物中，RPA内微量注射GABA(A)受体拮抗剂荷包牡丹碱(2 mM，30nL)使CSNA(+234+/-%)、HR(+91+/-10次/分)和平均AP(+16+/-3毫米汞柱)增加。摘除双侧肾上腺后也出现类似的心动过速，但用阿替洛尔阻断β-肾上腺素能受体后，心动过速消失。双侧微量注射GABA(A)受体激动剂Muscimol(6 mM，50nL)可抑制延髓头端腹外侧区(RVLM)的心血管交感前运动神经元，使头端RPA神经元的CSNA、HR和AP显著降低，从而引起CSNA和HR的等量百分比增加。这些结果表明，RPA含有一群神经元，可能是直接投射到脊髓-心脏交感节前神经元的交感运动前神经元，它们受到紧张性GABA能抑制，因此对CSNA和HR的静息水平没有显著贡献，但当它们被解除抑制时，它们可以引起CSNA和HR的大幅增加，与某些应激反应时的水平相当。(C)2003爱思唯尔B.V.保留所有权利。
We determined the cardiovascular effects of microinjecting the GABA,, receptor antagonist, bicuculline, into the rostral raphe pallidus (RPa) on arterial pressure (AP), heart rate (HR) and cardiac sympathetic nerve activity (CSNA) in urethane-chloralose anesthetized, artificially-ventilated rats. In 26 animals, microinjection of the GABA(A) receptor antagonist, bicuculline (2 mM, 30 nl), into RPa increased CSNA (+234+/-64% of control), HR (+91+/-10 bpm) and mean AP (+16+/-3 mmHg). A similar tachycardia was evoked after removal of both adrenal glands, but was absent after beta-adrenergic receptor blockade with atenolol. Equivalent percentage increases in CSNA and HR were evoked by disinhibition of the rostral RPa neurons after inhibition of cardiovascular sympathetic premotor neurons in the rostral ventrolateral medulla (RVLM) with bilateral microinjections of the GABA(A) receptor agonist, muscimol (6 mM, 50 nl) which markedly lowered CSNA, HR and AP. These results indicate that RPa contains a population of neurons, possibly sympathetic premotor neurons with direct projections to spinal cardiac sympathetic preganglionic neurons, that receive a tonic, GABAergic inhibition and thus do not contribute markedly to resting levels of CSNA and HR, but when disinhibited, they can produce large increases in CSNA and HR comparable to those seen during certain stress responses. (C) 2003 Elsevier B.V. All rights reserved.