The visceromotor response to colorectal distention fluctuates with the estrous cycle in rats
The visceromotor response to colorectal distention fluctuates with the estrous cycle in rats
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DOI：
10.1016/j.neuroscience.2008.04.070
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发表时间：
2008-07-17
期刊：
影响因子：
3.3
通讯作者：
Traub, R. J.
中科院分区：
文献类型：
--
作者：
Ji, Y.;Tang, B.;Traub, R. J.
在几种慢性疼痛综合征中存在性别差异以及月经周期中症状的波动强烈表明性激素参与疼痛处理。这些变化背后的机制还不清楚。在大鼠中使用结直肠扩张模型，我们先前报道了对扩张的反应的性别差异[Ji Y，Murphy AZ，Traub RJ（2006）吗啡诱导的内脏疼痛镇痛的性别差异是由脊柱上和外周介导的。Am J Physiol Regul Integr Comp Physiol 291：R307-R314]，并且卵巢切除术降低了对膨胀的反应，而雌激素替代逆转了这种降低[Ji Y，Murphy AZ，Traub RJ（2003）Estrogen modulates the visceriform reflex and responses of spinal dorsal horn neurons to colorectal stimulation in the rat. J Neurosci 23：3908-3915]，表明雌激素增加内脏伤害感受。在本研究中，我们测试的假设，内脏反应结直肠扩张波动与发情周期。三个测量（阴道涂片，输卵管重量和血浆雌激素浓度）用于确定发情期。比较了动情前期和动情后期/间情期的内脏反应阈值和幅度。我们的实验表明，扩张阈值显着较低，在发情前期（中位数：15毫米汞柱）相比，发情后期/间情期（中位数：25毫米汞柱）;和内脏反应的大小分级强度的结直肠扩张（20，40，60，80毫米汞柱）是显着较高的发情前期。结果表明，内脏反应波动与动情阶段，提供证据的内源性雌激素调节内脏伤害性处理，可能有助于性别差异。(C)2008年IBRO。由爱思唯尔有限公司出版。保留所有权利。
The existence of a sex difference in several chronic pain syndromes and the fluctuation of symptoms during the menstrual cycle strongly suggest sex hormones are involved in pain processing. The mechanisms underlying these changes are not well understood. Using the colorectal distention model in the rat, we previously reported a sex difference in the response to distention [Ji Y, Murphy AZ, Traub RJ (2006) Sex differences in morphine induced analgesia of visceral pain are supraspinally and peripherally mediated. Am J Physiol Regul Integr Comp Physiol 291:R307-R314] and that ovariectomy decreased the responses to distention while estrogen replacement reversed the decrease [Ji Y, Murphy AZ, Traub RJ (2003) Estrogen modulates the visceromotor reflex and responses of spinal dorsal horn neurons to colorectal stimulation in the rat. J Neurosci 23:3908-3915], suggesting estrogen increases visceral nociception. In the present study we tested the hypothesis that the visceromotor response to colorectal distention fluctuates with the estrous cycle. Three measurements (vaginal smears, uterine tube weight and plasma estrogen concentration) were used to determine the estrous phase. Comparison of the visceromotor response threshold and magnitude was made between proestrus and metestrus/diestrus. Our experiment demonstrated that the distention threshold was significantly lower in proestrus (median: 15 mm Hg) as compared with metestrus/diestrus (median: 25 mm Hg); and the magnitude of the visceromotor response to graded intensities of colorectal distentions (20, 40, 60, 80 mm Hg) was significantly higher in proestrus. The results indicate that the visceromotor response fluctuates with estrous phase, providing evidence for endogenous estrogen modulation of visceral nociceptive processing that could contribute to sex differences. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.