Dopamine-oxytocin interactions in penile erection
Dopamine-oxytocin interactions in penile erection
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DOI：
10.1111/j.1460-9568.2009.06999.x
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发表时间：
2009-12-01
影响因子：
3.4
通讯作者：
Douglas, A. J.
中科院分区：
文献类型：
--
作者：
Baskerville, T. A.;Allard, J.;Douglas, A. J.
多巴胺和催产素在大鼠阴茎勃起的中枢调节中起着重要作用；然而，涉及特定勃起环境的神经回路以及多巴胺和催产素机制之间的相互作用仍有待阐明。下丘脑的内侧视前区（MPOA）、视上核（SON）和室旁核（PVN）可能是候选位点，因为它们含有催产素细胞，接受多巴胺能输入，并参与介导男性性行为。双免疫荧光显示MPOA、SON和PVN中大量催产素细胞具有多巴胺D-2、D-3和D-4受体。在麻醉的大鼠中，使用海绵内压力作为勃起的生理指标，阻断腰骶叶催产素受体（UK, 427843）降低了对非选择性多巴胺激动剂（阿吗啡）的勃起反应，这表明多巴胺招募了室旁脊髓催产素通路。在没有雌性的有意识雄性中，D-2/D-3 （Quinelorane）而不是D-4 （PD168077）激动剂引起的阴茎勃起与内侧副细胞PVN催产素细胞的激活有关。在另一项实验中，雄性被给予完全接近接受性雌性的机会，D-4 （L-745870）而不是D-2或D-3拮抗剂（L-741626; nafadotride）抑制阴茎勃起（插入），这与SON大细胞催产素神经元激活有关。总之，这些数据表明，在阴茎勃起过程中，多巴胺对下丘脑催产素细胞的影响是特定环境的。多巴胺可能通过不同的微粒细胞和大细胞催产素亚群来引发勃起反应，这取决于是否进行了输入。这项研究表明，在阴茎勃起过程中，中枢多巴胺和催产素通路之间可能存在相互作用，而SON和PVN是整合位点。
Dopamine and oxytocin have established roles in the central regulation of penile erection in rats; however, the neural circuitries involved in a specific erectile context and the interaction between dopamine and oxytocin mechanisms remain to be elucidated. The medial preoptic area (MPOA), supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus may serve as candidate sites because they contain oxytocin cells, receive dopaminergic inputs and have been implicated in mediating masculine sexual behavior. Double immunofluorescence revealed that substantial numbers of oxytocin cells in the MPOA, SON and PVN possess dopamine D-2, D-3 and D-4 receptors. In anaesthetized rats, using intracavernous pressure as a physiological indicator of erection, blockade of lumbosacral oxytocin receptors (UK, 427843) reduced erectile responses to a nonselective dopamine agonist (apomorphine), suggesting that dopamine recruits a paraventriculospinal oxytocin pathway. In conscious males in the absence of a female, penile erection elicited by a D-2/D-3 (Quinelorane) but not D-4 (PD168077) agonist was associated with activation of medial parvocellular PVN oxytocin cells. In another experiment where males were given full access to a receptive female, a D-4 (L-745870) but not D-2 or D-3 antagonist (L-741626; nafadotride) inhibited penile erection (intromission), and this was correlated with SON magnocellular oxytocin neuron activation. Together, the data suggest dopamine's effects on hypothalamic oxytocin cells during penile erection are context-specific. Dopamine may act via different parvocellular and magnocellular oxytocin subpopulations to elicit erectile responses, depending upon whether intromission is performed. This study demonstrates the potential existence of interaction between central dopamine and oxytocin pathways during penile erection, with the SON and PVN serving as integrative sites.