Somatosensory stimuli evoke norepinephrine release in the anterior ventromedial hypothalamus of sexually receptive female rats
Somatosensory stimuli evoke norepinephrine release in the anterior ventromedial hypothalamus of sexually receptive female rats
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DOI：
10.1046/j.0007-1331.2001.00764.x
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发表时间：
2002-03-01
影响因子：
3.2
通讯作者：
Morales, JC
中科院分区：
文献类型：
--
作者：
Etgen, AM;Morales, JC
我们使用活体脑微透析来确定特定交配刺激在交配诱导荷尔蒙处理、性接受的雌性大鼠下丘脑外侧腹内侧核(VMH)去甲肾上腺素释放中的作用。去卵巢大鼠在腹外侧腹外侧VMH植入单侧引导管后，每日全身注射苯甲酸雌二醇，连续2天，在开始1小时的行为学测试前4小时注射黄体酮。在给予黄体酮后立即降低透析探头，并收集20min的透析样本，直到行为测试结束后1h。采用高效液相色谱-电化学检测法测定透析液中去甲肾上腺素的含量。在与雄性大鼠的交配试验中，在性接受能力强的雌性大鼠的腹透液中，去甲肾上腺素水平显著高于基线水平，这些雌性大鼠的探头放置在VMH的前部，而不是后部。如果大鼠不能接受，去甲肾上腺素水平不变，即使雄性大鼠奋力爬上，探头位于VMH前部。荷尔蒙处理过的女性在被男性弄脏的被褥上放置1小时后，其透析液中去甲肾上腺素的水平没有变化。同样，用阴道面罩防止刺激阴道颈的女性，即使表现出高水平的前凸行为，也没有显示出从VMH前部收集的透析液中去甲肾上腺素的水平增加。因此，去甲肾上腺素的释放不是执行前凸姿势的结果。这些发现表明，交配诱导的去甲肾上腺素释放增加，在激素处理的性接受性大鼠仅限于VMH的前部，并且躯体感觉刺激而不是化学感觉刺激引起去甲肾上腺素释放。此外，使用阴道面罩的实验表明，阴道刺激对于交配诱发的去甲肾上腺素在VMH前部的释放是必要的。
We used in vivo brain microdialysis to determine the role of specific copulatory stimuli in mating-induced release of norepinephrine in the lateral ventromedial hypothalamus (VMH) of hormone-treated, sexually receptive female rats. Ovariectomized rats implanted with a unilateral guide cannula aimed at the ventrolateral VMH received systemic injections of estradiol benzoate daily for 2 days before and progesterone 4 h before the initiation of a 1-h behavioural test. Dialysis probes were lowered immediately after progesterone administration, and 20-min dialysis samples were collected until 1 h after the termination of behavioural testing. Norepinephrine content of dialysates was quantified by high performance liquid chromatography with electrochemical detection. During mating tests with male rats, dialysate levels of norepinephrine increased significantly over baseline in sexually receptive females with probe placements in the anterior but not posterior VMH. Norepinephrine levels were unchanged if rats were nonreceptive, even if males mounted vigorously and probes were located in the anterior VMH. Hormone-treated females that were placed on male-soiled bedding for 1 h showed no changes in dialysate levels of norepinephrine. Similarly, females in which vaginocervical stimulation was prevented by a vaginal, mask failed to show increased levels of norepinephrine in dialysates collected from the anterior VMH, even if they displayed high levels of lordosis behaviour. Thus, the release of norepinephrine is not a result of executing the lordosis posture. The findings suggest that mating-induced increases in norepinephrine release in hormone-treated, sexually receptive rats are confined to the anterior VMH and that somatosensory rather than chemosensory stimuli evoke norepinephrine release. Moreover, experiments with vaginal masks indicate that vaginocervical stimulation is necessary for mating-evoked norepinephrine release in the anterior VMH.