Nonuniformity in the von Bezold-Jarisch reflex
Nonuniformity in the von Bezold-Jarisch reflex
复制标题
DOI：
10.1152/ajpregu.00099.2007
复制
发表时间：
2007-08-01
影响因子：
2.8
通讯作者：
McAllen, Robin M.
中科院分区：
文献类型：
--
作者：
Salo, Lauren M.;Woods, Robyn L.;McAllen, Robin M.
von Bezold-Jorich反射（BJR）是一种来自心脏和肺的迷走神经介导的化学反射，可引起呼吸不足、心动过缓和交感神经血管张力抑制。然而，心脏交感神经活动（CSNA）还没有系统地比较血管活性在BJR。在静脉注射1-1.5 g/kg麻醉的人工通气大鼠中，我们同时测量了CSNA和腰交感神经活动（LSNA），而13 JR由右心房推注苯基双胍（0.5、1.0、1.5和2 μ g）诱发。通过计算归一化累积和来分析神经和心跳反应。LSNA和心跳总是被13 JR降低。一个兴奋性的“反弹”的组成部分往往随后LSNA的抑制，但从来没有超过it.For CSNA，然而，兴奋通常（在7的11只大鼠）超过任何初始抑制，这样的净反应苯双胍是兴奋性的。LSNA、CSNA和心率之间的净反应差异均有显著性（P < 0.01）。第二个实验系列7只大鼠表明，甲基阿托品（1毫克/公斤iv）取消心动过缓的BJR，而随后的双边迷走神经切断术大幅减少LSNA和CSNA的反应，兴奋性和抑制性。这些发现表明，在BJR期间，1）CSNA经常被兴奋，2）可能存在对心脏的交感神经和副交感神经驱动的共激活，3）在心脏迷走神经、心脏交感神经和血管神经通路中可能同时诱发发散反应，以及4）这些发散反应主要由迷走神经介导。
The von Bezold-Jarisch reflex (BJR) is a vagally mediated chemoreflex from the heart and lungs, causing hypopnea, bradycardia, and inhibition of sympathetic vasomotor tone. However, cardiac sympathetic nerve activity (CSNA) has not been systematically compared with vasomotor activity during the BJR. In I I urethane-anesthetized (1-1.5 g/kg iv), artificially ventilated rats, we measured CSNA simultaneously with lumbar sympathetic activity (LSNA) while the 13JR was evoked by right atrial bolus injections of phenylbiguanide (0.5, 1.0, 1.5, and 2 mu g). Nerve and heartbeat responses were analyzed by calculating normalized cumulative sums. LSNA and heartbeats were always reduced by the 13JR. An excitatory "rebound" component often followed the inhibition of LSNA but never outweighed it. For CSNA, however, excitation usually (in 7 of 11 rats) outweighed any initial inhibition, such that the net response to phenylbiguanide was excitatory. The differences in net response between LSNA, CSNA, and heartbeats were all significant (P < 0.01). A second experimental series on seven rats showed that methyl atropine (1 mg/kg iv) abolished the bradycardia of the BJR, whereas subsequent bilateral vagotomy substantially reduced LSNA and CSNA responses, both excitatory and inhibitory. These findings show that, during the BJR, 1) CSNA is often excited, 2) there may be coactivation of sympathetic and parasympathetic drives to the heart, 3) divergent responses may be evoked simultaneously in cardiac vagal, cardiac sympathetic, and vasomotor nervous pathways, and 4) those divergent responses are mediated primarily by the vagi.