Brain serotonin and angiotensin II systems in migraine

描述（由申请人提供） 长期目标。脑内5-羟色胺（5-HT）系统在脑血管和神经内分泌调节中起重要作用。这些系统与偏头痛有关。偏头痛是一种低5-HT综合征，发作可能是由大量释放5-HT作用于致敏受体引发的。这一建议将阐明5-HT神经传递减少的现象与脑血管和神经内分泌反应性改变之间的关联。重点将放在最近参与偏头痛发病机制和/或预防性治疗的5-HT受体（5-HT 1A，5-HTT，5-HT 2s和5-HT 2c）。作为下丘脑-垂体-肾上腺（HPA）轴的关键激活剂，脑血管紧张素II（Ang II）系统的作用将得到解决。该提案旨在阐明偏头痛的病理生理机制，以及偏头痛预防性5-HT和Ang II药物的作用机制。具体目标。以下假设将受到挑战：1）脑中5-HT传递的降低将导致脑血管系统和HPA轴中5-HT受体亚型的敏化和/或上调;用靶向这些受体的偏头痛预防性化合物治疗将恢复5-HT受体功能和/或表达。这可能是一个有用的偏头痛预防药物筛选的动物模型。2)对应激的反应涉及脑Ang II和HPA系统的顺序激活，将导致脑5-HT水平降低、5-HT受体上调和/或对5-HT受体激活的神经内分泌和脑血管反应增强;用Ang II合成抑制剂治疗将恢复血管紧张素能功能。设计1)将在对照和5-HT耗竭Wistar大鼠中测定对5-HT激动剂的脑血管和神经内分泌反应以及脑血管和HPA轴中5-HT受体的表达。将确定用偏头痛预防性5-HT拮抗剂长期治疗是否恢复5-HT受体功能和/或表达。2)将在对照和应激（急性和慢性隔离和束缚）Wistar大鼠中测定脑5-HT含量、HPA轴中5-HT受体的表达以及神经内分泌和脑血管反应。将尝试通过血管紧张素转换酶抑制剂赖诺普利（即偏头痛预防剂）的长期治疗来抑制这些变量中的应激诱导的变化。将通过激光多普勒血流仪（皮质血流量）和4-碘-[N-甲基-14 C]-安替比林方法（局部脑血流量）评估体内脑血管反应性。将使用动脉造影室系统分析体外脑血管反应性。将通过放射免疫分析测定血样中的激素反应（ACTH、皮质酮和催乳素），并通过定量受体放射自显影术测定组织切片中的5-HT受体表达。将通过HPLC测定脑匀浆中的5-HT含量。

DESCRIPTION (provided by applicant) Long-term objectives. The brain serotonin (5-HT) system plays an important role in cerebrovascular and neuroendocrine control. These systems have been implicated in migraine. Migraine is a low 5-HT syndrome and attacks may be triggered by a massive release of 5-HT acting on sensitized receptors. This proposal will elucidate the association between the phenomena of decreased 5-HT neurotransmission and altered cerebrovascular and neuroendocrine responsiveness. Focus will be on 5-HT receptors recently implicated in migraine pathogenesis and/or prophylactic treatment (5-HT1A, 5-HTT, 5-HT2s and 5-HT2c). As a key activator of the hypothalamic-pituitary-adrenal (HPA) axis, the role of the brain angiotensin II (Ang II) system will be addressed. The proposal intends to shed light into the pathophysiological mechanisms of migraine, and the mechanism of action of migraine prophylactic 5-HT and Ang II drugs. Specific aims. The following hypotheses will be challenged: 1) A decreased 5-HT transmission in the brain will cause sensitization and/or up-regulation of 5-HT receptor subtypes in the cerebral vasculature and the HPA axis; treatment with a migraine prophylactic compound that target these receptors will restore 5-HT receptor function and/or expression. This may be a useful animal model for drug screening in migraine prophylaxis. 2) The response to stress, which involves sequential activation of the brain Ang II and the HPA systems, will lead to decreased brain 5-HT levels, up-regulation of 5-HT receptors, and/or amplified neuroendocrine and cerebrovascular responses to 5-HT receptor activation; treatment with an inhibitor of Ang II synthesis will restore serotonergic function. Design. 1) Cerebrovascular and neuroendocrine responses to 5-HT agonists, and expression of 5-HT receptors in the cerebral vasculature and the HPA axis, will be determined in control and 5-HT-depleted Wistar rats. It will be determined whether chronic treatment with a migraine prophylactic 5-HT antagonist restore 5-HT receptor function and/or expression. 2) Brain 5-HT content, expression of 5-HT receptors in the HPA axis, and neuroendocrine and cerebrovascular responses will be determined in control and stressed (acute and chronic isolation and restraint) Wistar rats. Reversal of stress-induced changes in these variables will be attempted by chronic treatment with the angiotensin-converting enzyme inhibitor, lisinopril (i.e. a migraine prophylactic agent). In vivo cerebrovascular reactivity will be assessed by laser- Doppler flowmetry (cortical blood flow) and the 4-iodo-[N-methyl-14C]-antipyrine method (regional cerebral blood flow). In vitro cerebrovascular reactivity will be analyzed with an arteriographic chamber system. The hormonal response (ACTH, corticosterone and prolactin) will be measured by radioimmuno assay in blood samples and 5-HT receptor expression will be determined by quantitative receptor autoradiography in tissue sections. 5-HT content will be measured by HPLC in brain homogenates.