Midbrain modulation of the cardiac baroreflex involves excitation of lateral parabrachial neurons in the rat
Midbrain modulation of the cardiac baroreflex involves excitation of lateral parabrachial neurons in the rat
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DOI：
10.1016/j.brainres.2007.01.140
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发表时间：
2007-05-11
期刊：
影响因子：
2.9
通讯作者：
Hayward, Linda F.
中科院分区：
文献类型：
--
作者：
Hayward, Linda F.
激活背侧中脑导水管周围灰质(PAG)可引起类似防御的行为，包括交感神经冲动显着增加和压力感受器反射功能重置。本研究的目的是探讨臂旁外侧核(LPBN)在调节动脉压力感受器反射中的作用。电刺激乌拉坦麻醉大鼠(n=18)的主动脉降压神经(ADN)，以5或15 Hz的频率诱发反射反应。电刺激PAG背侧10 Hz不改变基础平均动脉压(MAP)，但显著减弱低频ADN对心率(HR)的压力感受性反射控制。另外，在两种ADN刺激频率下，刺激40 Hz背侧PAG可增加基础MAP(43+/-3 mm Hg)和HR(33+/-3次/分)，减弱压力感受性反射对HR的控制。刺激背侧PAG对MAP的反射控制基本无影响。双侧抑制LPBN区神经元(n=6)，可使PAG诱发的MAP和HR分别降低50+/-4%和95+/-4%，但不能完全消除心脏压力感受器反射的PAG衰减。用犬尿酸(1.8nmoL)阻断双侧LPBN区谷氨酸受体，对背侧PAG诱发的MAP、HR和心脏压力感受性反射功能的增加也有类似的影响。MAP的反射控制在任何一种治疗中都没有变化。这些发现表明，LPBN区是参与防御行为中心脏压力感受性反射功能下行调节的几个脑干区之一。(C)2007 Elsevier B.V.保留所有权利。
Activation of the dorsal periaqueductal gray (PAG) evokes defense-like behavior including a marked increase in sympathetic drive and resetting of baroreflex function. The goal of this study was to investigate the role of the lateral parabrachial nucleus (LPBN) in mediating dorsal PAG modulation of the arterial baroreflex. Reflex responses were elicited by electrical stimulation of the aortic depressor nerve (ADN) at 5 Hz or 15 Hz in urethane anesthetized rats (n = 18). Electrical stimulation of the dorsal PAG at 10 Hz did not alter baseline mean arterial pressure (MAP) but did significantly attenuate baroreflex control of heart rate (HR) evoked by low frequency ADN stimulation. Alternatively, 40 Hz dorsal PAG stimulation increased baseline MAP (43 +/- 3 mm Hg) and HR (33 +/- 3 bpm) and attenuated baroreflex control of HR at both ADN stimulation frequencies. Reflex control of MAP was generally unchanged by dorsal PAG stimulation. Bilateral inhibition of neurons in LPBN area (n = 6) with muscimol (0.45 nmol per side) reduced dorsal PAG-evoked increases in MAP and HR by 50 +/- 4% and 95 +/- 4%, respectively, and significantly reduced, but did not completely eliminate dorsal PAG attenuation of the cardiac baroreflex. Bilateral blockade of glutamate receptors in the LPBN area (n=6) with kynurenic acid (1.8 nmol) had a similar effect on dorsal PAG-evoked increases in MAP, HR and cardiac baroreflex function. Reflex control of MAP was unchanged with either treatment. These findings suggest that the LPBN area is one of several brainstem regions involved in descending modulation of the cardiac baroreflex function during defensive behavior. (c) 2007 Elsevier B.V. All rights reserved.