POWERFUL DEPRESSOR AND SYMPATHOINHIBITORY EFFECTS EVOKED FROM NEURONS IN THE CAUDAL RAPHE PALLIDUS AND OBSCURUS
POWERFUL DEPRESSOR AND SYMPATHOINHIBITORY EFFECTS EVOKED FROM NEURONS IN THE CAUDAL RAPHE PALLIDUS AND OBSCURUS
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DOI：
10.1152/ajpregu.1995.268.5.r1295
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发表时间：
1995-05-01
影响因子：
2.8
通讯作者：
DAMPNEY, RAL
中科院分区：
文献类型：
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作者：
COLEMAN, MJ;DAMPNEY, RAL
将谷氨酸显微注射到髓中缝核（苍白核和暗核）内的位置，在麻醉兔子中，导致平均动脉压（MAP）、肾交感神经活动（RSNA）和心率呈剂量依赖性下降。在完整动物和去神经支配动物中，降压和交感抑制反应的强度与先前描述的尾侧腹外侧髓质（CVLM）降压区域引起的反应相似，但持续时间较短。压力神经支配不会改变心动过缓，但在服用普萘洛尔或阿托品后会减轻，并在服用这两种药物后消失。神经抑制化合物 γ-氨基丁酸或蝇蕈醇在注射到尾髓中缝核时对 MAP 或 RSNA 没有影响，但当注射到 CVLM 时会引起加压和交感兴奋反应。结果表明，中缝苍白尾部和暗部内的神经元可以强烈抑制交感神经活动，但与CVLM中的交感抑制神经元不同，它们不具有强直活性，并且不能产生动脉压和交感神经活动的持续变化。
Microinjection of glutamate into sites within the medullary raphe nuclei (pallidus and obscurus) at levels caudal to the obex resulted in a dose-dependent decrease in mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and heart rate in anesthetized rabbits. The depressor and sympathoinhibitory responses were similar in magnitude to those elicited from the previously described depressor region in the caudal ventrolateral medulla (CVLM) but had a shorter duration, in both intact and barodenervated animals. The bradycardia was not altered by barodenervation but was reduced after administration of propranolol or atropine and abolished after administration of both drugs. The neuroinhibitory compounds gamma-aminobutyric acid or muscimol had no effect on MAP or RSNA when injected into the caudal medullary raphe nuclei but evoked a presser and sympathoexcitatory response when injected into the CVLM. The results indicate that neurons within the caudal raphe pallidus and obscurus can powerfully inhibit sympathetic activity, but unlike sympathoinhibitory neurons in the CVLM, they are not tonically active and are not capable of producing sustained changes in arterial pressure and sympathetic activity.