5-HT及其2A受体在大鼠丘脑前核的表达

目的研究5-羟色胺(5-HT)及其5-羟色胺2A受体(5-HT2AR)在大鼠丘脑前核的表达,探讨两者参与学习记忆的形态学依据。方法免疫组织化学ABC法观察5-HT及5-HT2AR在丘脑前核内的表达情况。包埋前免疫电镜技术观察丘脑前核群的5-HT能投射纤维终末。结果免疫组化结果显示:在大鼠丘脑前核群的前、中、后部均可见阳性的5-HT能神经元及大量串珠状的投射纤维终末,其中背侧核(AD)的神经元着色较深,胞体较大,纤维密集,平均光密度值(A值)与腹侧核(AV)的比较差异显著(P0.05);5-HT阳性反应产物主要定位于胞浆内,胞核不着色。包埋前免疫电镜显示:阳性5-HT能轴突终末与树突形成非对称性的轴-树突触。在AD、AV内可见黄色的5-HT2AR阳性神经元,其中AD的神经元胞体较大,着色较AV深,阳性产物灰度值二者比较差异显著(P0.05);阳性产物主要定位于神经元胞膜,胞核不着色。结论 5-HT和5-HT2AR在大鼠丘脑前核表达,在AD、AV的表达强度不同。     

大鼠海马内5-羟色胺及其受体5-HT2A的表达

目的:观察5-羟色胺(5-HT)纤维和5-HT2A受体在大鼠海马CA1、CA2和CA3三个区域的分布特点.方法:用5-HT递质和5-HT2A受体特异性抗体的免疫组织化学显色以及图像处理与分析.结果:在海马内,抗5-HT2A受体的免疫反应阳性产物主要位于锥体细胞的细胞膜和树突,树突染色较深;5-HT2A受体的阳性胞体在C...     

大鼠前庭神经核复合体内5-羟色胺1A受体的分布

为了研究5-羟色胺1A受体(5-HT1AR)亚型在大鼠前庭神经核复合体(VNC)内的分布情况,本文采用免疫组织化学方法,在光学显微镜下对5-HT1AR亚型免疫阳性结构进行了观察。结果显示:5-HT1AR免疫阳性产物在VNC各个核团全长均有分布,主要定位于VNC神经元的胞体和近侧端树突,呈弥散分布,但在胞浆中也观察到许多染色深浅不同、分布不均匀的点状阳性结构。其中5-HT1AR样阳性神经元在前庭内侧核的全长呈密集分布,在前庭下核的尾段呈中等密度分布,在前庭上核、前庭外侧核和X核的全长、前庭下核的吻段和中段以及Y核的中、尾段均呈低密度分布,Y核的吻侧呈稀疏分布。本文结果提示,5-HT1AR阳性结构广泛地分布于大鼠VNC内,它们可能在介导5-HT对神经元活动的调节,参与前庭信息的整合与加工方面发挥重要作用。     

雌性大鼠下丘脑5-羟色胺1A和2A受体亚型的定位分布

本研究应用免疫细胞化学技术观察了雌性成年SD大鼠下丘脑内5-HT1A受体亚型(5-HT1AR)和5-HT2AR免疫阳性结构的分布。结果显示:5-HT1AR免疫阳性神经元在视前区大细胞核、视前室周核、视上核和下丘脑外侧前核等核团内密集分布。在内侧视前核、外侧视前区、下丘脑室周核、下丘脑外侧区、背内侧核、腹内侧核、结节核、结节乳头体核、乳头体内侧核和乳头体外侧核等结构内也有较多的分布;而在正中视前核、视交叉上核、下丘脑室旁核、下丘脑背侧核、弓状核、乳头体上核和乳头体前核等部位有散在的分布。与5-HT1AR不同,5-HT2AR免疫阳性反应产物主要见于纤维和终末,阳性胞体少且染色淡。5-HT2AR阳性胞体见于下丘脑室旁核、视上核、腹内侧核、结节核、视前内侧区、外侧区、外侧前核、下丘脑背内侧核等处。另外,在视前区前内侧视前核、视交叉上核背侧和外侧可见围绕血管分布、密集成团簇状、带有大小不同膨体的阳性神经纤维缠结。本文结果提示5-HT1AR阳性结构广泛地分布于大鼠下丘脑,而5-HT2AR在下丘脑分布较为局限。二者不同的分布特点,提示它们可能介导5-HT在下丘脑的不同生理功能。     

GAD_(67)-GFP基因敲入小鼠脊髓背角GABA能神经元与不同5-HT受体亚型的共存研究

为初步探讨5-HT受体亚型对脊髓背角内抑制性GABA能神经元的介导作用,本研究以GAD67-GFP基因敲入小鼠为工具,利用免疫荧光双标记方法,检测了5-HT受体亚型与脊髓背角GABA能阳性神经元的共存情况。结果显示,GABA能阳性细胞与5-HT1A,5-HT2A和5-HT3等受体亚型共存,且共存率存在明显不同。以上结果提示5-HT受体各亚型在脊髓水平发挥不同的作用,从而参与完成5-HT复杂的生理效应。     

大鼠前庭神经核复合体内5-HT能终末与表达5-HT1A受体的前庭-臂旁核投射神经元之间的联系

目的 观察大鼠前庭神经核复合体(VNC)内5-羟色胺(5-HT)样阳性终末与表达5-HT1A受体(5-HT1A R)的前庭-臂旁核投射神经元之间的联系.方法 运用逆行束路追踪和免疫荧光组织化学染色相结合的双重标记技术,在激光共焦显微镜下观察.结果 将四甲基罗达明(TMR)注入臂旁核后,在双侧VNC的各个核团内均可观察到许多TMR逆标神经元,但以同侧为主.免疫荧光组织化学染色结果显示,在前庭内侧核(MVe)、前庭下核(SpVe)、前庭上核(SuVe)、前庭外侧核(LVe)、X核以及Y核的一些区域内,许多神经元表达5-HT1A R样免疫阳性,并可观察到大量5-HT样阳性纤维和终末.激光共焦显微镜下可进一步观察到一些TMR逆标神经元同时呈5-HT1A R样免疫阳性,且有部分5-HT样阳性终末与TMR/5-HT1A R双标神经元的胞体或树突形成密切接触.结论 提示5-HT可能通过5-HT1A R对前庭神经核复合体-臂旁核间的信息传递发挥调控作用.     

5-羟色胺2A受体与疼痛

5-羟色胺(5-HT)是一种内源性的活性物质,5-HT具有多种受体亚型。在中枢可以通过2A受体引起抑制性神经递质γ-丁氨酸（GABA ）等的释放，从而发挥镇痛作用；在外周参与伤害性感受器的活化,促进伤害性信息的传递。组织损伤以及炎症状态下,血小板和肥大细胞即释放5-HT。5-HT2A受体可介导5-HT引起的疼痛,该受体可以作为开发外周镇痛药物的重要靶点。     

5-羟色胺对正常大鼠丘脑底核神经元放电的双向效应

目的观察5-HT对正常大鼠丘脑底核神经元放电频率的影响及其作用机制。方法用多管微电极在体细胞外电生理记录观察5-HT及5-HT1B、5-HT2C、5-HT4和5-HT1A受体激动剂对丘脑底核神经元的电生理效应,免疫组织化学法观察丘脑底核神经元4种受体亚型的表达情况。结果 5-HT既可使丘脑底核神经元的自发放电频率明显升高(P0.001),也可使其明显降低(P0.05)。作为5-HT受体激动剂,CP-93129、RO-600175和ML-10302可明显增加丘脑底核神经元的放电频率(CP-93129:P0.001;RO-600175:P0.01;ML-10302:P0.001),8-OHDPAT则使其放电频率明显降低(P0.01)。正常大鼠丘脑底核表达丰富的5-HT1B、5-HT2C、5-HT4和5-HT1A受体。结论 5-HT可以改变正常大鼠丘脑底核神经元的兴奋性,产生使放电频率升高和降低的双向效应。5-HT的这种兴奋效应主要是通过激活5-HT1B、5-HT2C和5-HT4受体实现的,而抑制效应则与5-HT1A受体的激活有关。     

成年大鼠Pre-Btzinger复合体5-羟色胺样阳性神经纤维与神经激肽1受体样阳性神经元的关系

位于新生和成年哺乳动物延髓腹外侧区的Pre-Bo¨tzinger复合体(pre-Bo¨tzinger complex,PBC)被认为是呼吸节律产生中枢,神经激肽1受体(neurokinin-1receptor,NK1R)是PBC神经元的主要标记物。5-羟色胺(5-hydroxytryptamine,5-HT或seroto-nin)作为一种重要的神经递质,可通过其受体调节呼吸中枢的节律性变化。本研究采用免疫荧光组织化学和免疫电镜双重标记技术,在激光共聚焦显微镜和电子显微镜下观察了大鼠PBC内5-HT样免疫阳性神经纤维与NK1R样免疫阳性神经元或NK1R免疫阴性神经元之间的关系,旨在为5-HT参与PBC神经元呼吸节律的产生和调控提供形态学依据。共聚焦显微镜结果显示:正常大鼠PBC内可观察到一定数量的5-HT样阳性纤维和终末,且有少量的阳性纤维和终末与PBC内NK1R样阳性神经元的胞体或树突形成密切接触。在电镜下可进一步观察到:5-HT样阳性纤维终末可与NK1R样阳性神经元的树突形成直接接触,但未观察到典型的突触联系。5-HT样阳性纤维终末可与NK1R免疫阴性的树突形成非对称性突触。本实验结果提示:5-HT可能通过旁分泌的方式或通过中间神经元间接调节PBC内NK1R样阳性神经元的活动,以实现对中枢呼吸节律的调控。     

5-HT_(2~7)受体亚型mRNAs在坐骨神经分支选择性损伤模型大鼠背根神经节的表达变化

本研究利用反转录 聚合酶链式反应(RT- PCR)方法,观察了坐骨神经分支选择性损伤(SNI)所致神经病理性痛条件下,大鼠背根神经节(DRG)中 5- HT2~7受体亚型mRNAs的时程表达变化。用RT- PCR方法在正常大鼠DRG中检测到 5-HT2A、5- HT3、5- HT4、5 -HT5A和 5 HT7受体亚型mRNAs的表达,但未检测到 5 -HT2B、5- HT2C、5- HT5B和 5 -HT6受体亚型mRNAs。SNI能诱导 5 -HT2A、5- HT3、5 -HT4 和 5- HT7受体亚型mRNAs在损伤侧DRG的表达上调。其中, 5- HT2A受体亚型mRNA的表达在术后 3d时开始升高,持续增加至 28d; 5- HT3 受体亚型mRNA的表达在术后 4d时明显增加, 14d时达到高峰; 5- HT4受体亚型mRNA于术后 3d的表达明显增加, 21d时达到高峰; 5-HT7 受体亚型mRNA的表达在术后 1d时即显著升高,一直维持高水平的表达至28d。未检测到 5- HT5A受体亚型mRNA的表达变化。在SNI对侧的DRG,各受体亚型mRNAs的表达未出现明显变化。部分 5- HT受体亚型在SNI模型DRG的表达具有不同的时程变化特点,提示它们在SNI所致的神经病理性痛中发挥着不同的作用。     

低氧性肺动脉高压大鼠肺内5-HT_(1B)受体的分布和表达变化

目的:观察低氧性肺动脉高压(HPH)大鼠体内5-羟色胺(5-HT)水平及其肺内5-羟色胺1B(5-HT1B)受体的分布和表达变化,探讨低氧性肺动脉高压的形成机制。方法:40只健康雄性SD大鼠随机分为正常组(control)、低氧3周组、低氧4周组和低氧5周组。除正常组外,其余3组大鼠分别在低氧环境中饲养3周、4周和5周。测定各组大鼠的平均肺动脉压力(mPAP)、右心室收缩压(RVSP)、右心室肥厚度[RV/(LV+S)%]、血浆和肺组织中5-HT含量。应用免疫组织化学法观察大鼠肺组织中5-HT1B受体的分布和表达,Western blotting法测定大鼠肺组织中5-HT1B受体的蛋白含量。结果:和正常组相比,低氧3周组大鼠的mPAP、RVSP和右心室肥厚度均显著升高(均P0.05),并且随着低氧时间的延长而持续升高(均P0.05)。低氧大鼠血浆和肺组织中5-HT的含量均显著高于正常组大鼠(均P0.05),并随着低氧时间的延长而持续升高(均P0.05)。免疫组织化学结果显示:5-HT1B受体主要分布在正常大鼠肺动脉的内膜层,而平滑肌层中仅有少量表达;和正常组相比,低氧3周组大鼠肺动脉平滑肌层中5-HT1B受体的表达显著增多;随着低氧时间的延长,大鼠肺动脉平滑肌层中5-HT1B受体表达持续增多。Western blotting结果表明,大鼠肺组织中5-HT1B受体的蛋白含量变化和免疫组织化学结果相一致。结论:低氧性肺动脉高压大鼠体内5-HT水平显著升高,其肺动脉中5-HT1B受体呈过度表达,这可能是低氧性肺动脉高压形成的分子机制之一。     

Association Analysis of TPH2, 5-HT2A,and 5-HT6 With Executive Function in a Young Chinese Han Population

Abstract: The 5-hydroxytryptamine (5-HT) system is widely distributed in the central nervous system. A growing body of evidence has suggested that the neurotransmitter system is implicated in the functions of the prefrontal cortex. So far, several studies have revealed that some functional genetic variants in TPH2, 5-HT2A, and 5-HT6 genes are possibly related to executive function. To investigate the potential influences of TPH2, 5-HT2A, and 5-HT6 on the components of executive function, the authors performed a population-based study with standard cognitive paradigms in a young Chinese Han group. The results indicated that ?703 G/T polymorphism of TPH2 was associated with the performance of response inhibition (p = .002) and the T allele carriers (TT and GT) had fewer errors than the noncarriers (GG) did in the response inhibition test. Furthermore, there were no significant associations of the T102C in 5-HT2A and T267C in 5-HT6 with the components of executive function after correcting for multiple tests (p > .05). The present study suggests that TPH2 contributes distinctively to the inhibition domain of executive function, whereas 5-HT2A and 5-HT6 show no striking effects on executive function in the Chinese Han population.     

Time-course of alterations in morphine-induced analgesia and nociceptive threshold following medullary raphe lesions

Electrolytic lesions which included major portions of the nucleus raphe magnus produced alterations in nociceptive threshold and morphine-induced analgesia. These effects were highly dependent on the time at which measurements were made following the lesioning procedure. Seven days or less after placement of the lesions there was a pronounced decrease in nociceptive threshold, but no effect on the capacity of morphine to induce antinociception. However, the nociceptive threshold exhibited recovery by 21–28 days, during which time there was a gradual, but profound, decrease in the capacity of morphine to induce analgesia. At longer times after the placement of lesions (28–35 days), the nociceptive threshold, assessed using the tail-flick test, became elevated concomitant with a recovery of morphine's analgesic potency.The differential time course of the lesion-induced attenuation of morphine analgesia and decrease in nociceptive threshold suggests that these effects result from the destruction of separate neuronal systems. Thus, the lesion-induced decrease in nociceptive threshold probably results from destruction of raphespinal serotonergic neurons while the attenuation of morphine analgesia is most likely an indirect result of damage to non-serotoninergic raphe-spinal neurons. Finally, the failure of acute raphe lesions to alter morphine analgesia indicates that the neurons found in the raphe magnus are not directly involved in mediating the antinociceptive actions of opiates.     

Organization of ascending serotonin systems in the adult rat brain. A radioautographic study after intraventricular administration of [3h]5-hydroxytryptamine

Light microscope radioautography was used to visualize ascending serotonin (5-HT) systems in adult rat brain, following prolonged latero-ventricular instillation of [³H]5-HT. In paraventricular and paracisternal regions, the cell bodies, axonal projections and terminal fields of 5-HT neurons were distinctly labelled, allowing comprehensive analysis of their organizational features. Two major systems of ascending 5-HT fibers could be defined: a transtegmental system originating mainly from nucleus raphe dorsalis (B-7 and B-6) and less prominently from nucleus raphe medianus (B-8), and a periventricular system predominantly issuing from the rostral pole of nucleus raphe dorsalis (B-7). The transtegmental system converges ventral-ward across the decussation of the superior cerebellar peduncles and sweeps rostral-ward, through the ventral tegmental decussation, to enter the ventral tegmental area. The periventricular system closely follows the dorsal longitudinal fasciculus of Schu¨tz. It branches off dorsally toward the superior and inferior colliculi and the subcommissural organ, but the bulk of its fibres arch abruptly ventralward, beneath the posterior commissure, to reach the dorsal hypothalamus. Along their way, these axons most likely contribute to the dense 5-HT innervation of the periventricular gray matter of the midbrain and caudal diencephalon. Both ascending 5-HT systems merge in the medial forebrain bundle area of caudal hypothalamus, wherefrom their fibres borrow several limbic pathways to reach distant territories of innervation: fasciculus retroflexus to medial habenula; striae medullaris and terminalis toward the habenula and the amygdala, respectively; fornix to hippocampus; diagonal band of Broca to septum; induseum griseum and cingulate bundle to hippocampus and neocortex. Other fibers spread more laterally, across the internal capsule, to innervate the globus pallidus and neostriatum. Finally, at the base of anterior forebrain, some 5-HT axons traverse the anterior olfactory nucleus and end in the glomerular layer of olfactory bulb.These and additional results concerning the heterogeneous distribution of 5-HT axonal varicosities in various parts of forebrain (e.g. thalamus, hypothalamus, septal area and amygdaloid complex) complement earlier data gathered by means of other neuroanatomical techniques and make it possible to present a useful model of the general organization of ascending 5-HT systems in the mammalian brain.     

5-HTR2A基因启动子区-1438G/A多态性与抗精神病药源性肥胖的核心家系关联研究

目的探讨中国汉族首发精神分裂症(schizophrenia,SCH)患者抗精神病药物(antipsychoticagents,APS)治疗过程中体重增加是否与五羟色胺2A受体(5-hydroxytryptamine2Areceptor,5-HTR2A)基因启动区-1438G/A多态性相关。方法对84例首发精神分裂症患者(包含完整核心家系70个)APS(氯丙嗪或利培酮)单药治疗10周,治疗前后测量体重并计算体重指数。采用聚合酶链反应-限制性片段长度多态技术分析5-HTR2A基因启动区-1438G/A多态性基因型和等位基因分布频率,进行APS所致体重增加与5-HTR2A基因启动区-1438G/A多态性的相关分析、传递不平衡检验及数量性状传递不平衡检验。结果治疗10周后患者体重较基础体重增加(8.00±6.13)%。APS治疗10周后,体重增加≥7%和<7%患者组间,5-HTR2A基因-1438G/A多态性各基因型和等位基因分布频率差异均无统计学意义(P>0.05)。5-HTR2A基因-1438G/A多态性的各基因型之间各项指标的差异均无统计学意义(P>0.05);同时未发现5-HTR2A基因-1438G/A在不同体重增加组间存在传递不平衡。结论5-HTR2A基因-1438G/A多态性可能不是影响APS所致体重增加的主要遗传因素。     

The effect of tryptolines (1, 2, 3, 4-tetrahydro-β-carbolines) on monoamine metabolism and the platelet aggregation response in human platelets

Tryptolines (1, 2, 3, 4-tetrahydro-β-carbolines) are structurally related to 5-hydroxytryptamine. Using the human platelet preparation as a model of central serotoninergic neurons the action of various tryptolines on 5-hydroxytryptamine and epinephrine metabolism have been examined. All these compounds are competitive selective inhibitors of monoamine oxidase ‘type A’, 5-hydroxytryptamine being ‘type A’ substrate. 5-hydroxytryptoline and 5-methoxytryptoline are the most active monoamine oxidase inhibitors with IC₅₀ 0.5 μm and 1.5 μm respectively using 5-hydroxytryptamine as substrate. Tetrahydro-β-carbolines are also potent uptake inhibitors of 5-hydroxytryptamine and epinephrine; a significantly greater uptake inhibitory selectivity being shown for 5-hydroxytryptamine than epinephrine. Platelet aggregation response induced by 5-hydroxytryptamine, epinephrine and adenosine 5'-diphosphate are mediated by specific receptors on the platelet. Tetrahydro-β-carbolines by themselves do not induce platelet aggregation but are potent inhibitors of 5-hydroxytryptamine and epinephrineinduced aggregation. However, they are ineffective on aggregation induced by adenosine 5'-diphosphate. The comparison of the inhibition kinetics of tetrahydro-β-carbolines for 5-hydroxytryptamine and epinephrine uptake with that of the platelet aggregation response to these amines have shown that 5-hydroxymethtryptoline, methtryptoline, and tryptolin are poor inhibitors of uptake. However, 5-hydroxymethtryptoline and tryptoline are potent inhibitors of the aggregation response. It is suggested that tryptoline derivatives can distinguish between receptors for uptake and the platelet aggregation response to 5-hydroxytryptamine. In all respects 5-hydroxytryptoline and 5-methoxytryptoline showed greater pharmacological activity than the tryptoline and methtryptoline.Although the in vivo formation of tryptolines has been a matter of controversy, they have profound pharmacological activity. This is reflected in their actions described above. The results confirm what has been observed using rat brain preparations and would suggest that human platelets can be used as a model to study the action of these compounds on central serotoinergic neurons.     

5-羟色胺及其受体在大鼠舌下腺的免疫组织化学研究

用免疫组织化学ABC法研究了大鼠舌下腺中5-羟色胺及其受体的分布情况,结果表明大鼠舌下腺的混合性腺泡的浆液性腺细胞、纹状管的上皮细胞均呈5-羟色胺免疫反应阳性.邻片双标染色发现5-羟色胺免疫反应阳性细胞也呈5-羟色胺受体免疫反应阳性,提示大鼠舌下腺有自分泌5-羟色胺之功能.     

Electrically induced release of labelled taurine, alpha- and beta-alanine, glycine, glutamate and other amino acids from rat neocortical slices in vitro

The electrically induced release of labelled alpha-aminoisobutyrate, L-alpha-alanine, beta-alanine, glycine, histidine, serine, glutamate, aspartate and taurine, from superfused thin slices of the rat neocortex, held on quick-transfer electrodes was studied. In no instance did the release of these substances resemble that of (3H)-labelled noradrenaline, acetylcholine or 5-hydroxytryptamine, which can be released by 0.5-3 V stimuli and whose release shows an absolute dependency on calcium ions. Small amounts of alpha-aminoisobutyrate, beta-alanine, serine, glutamate and aspartate were released with 4 V stimuli, but the release was statistically significant for the first two substances only. Following incubation with (3H)-histidine, substantial labelling of homocarnosine was found, but no electrically induced release of this dipeptide could be detected. With (14C)-taurine, however, small but significant release was found with sinewave stimuli of 1.5 V or higher. Such release was significantly increased in the absence of calcium ions. Biphasic pulses of frequencies ranging between 10 and 100 Hz. (1 V, 3 ms duration) did not evoke the release of (14C)-taurine, although this type of stimulation readily induced the release of (3H)-noradrenaline studied simultaneously. Differences in threshold, calcium dependency and shape of the taurine efflux peak, relative to that seen with (3H)-noradrenaline and other transmitters, suggest that taurine release occurs by mechanisms unrelated to those that mediate transmitter secretion. The release of all the above amino acids can readily be elicited, however, if stimuli that are too intense, prolonged or damaging are utilized. The occurrence of these artifacts in the present and in previous work is discussed.     

Actions of serotonin antagonists on cholera-toxininduced intestinal fluid secretion

The effects of several 5-hydroxytryptamine (5-HT) receptor antagonists were tested in rats in vivo on the intestinal fluid secretion evoked by cholera toxin. Five receptor antagonists were used, namely 2-bromolysergic acid diethylamine (2-bromo-LSD), granisetron, ketanserin, methysergide and ondansetron. The drugs were used in doses that inhibited the arterial hypertension and/or bradycardia evoked by 5-HT given i.v. Granisetron and ondansetron markedly diminished cholera-toxin-evoked secretion, whereas ketanserin was without any effect. Methysergide also diminished cholera-toxininduced fluid secretion particularly when the drug was given as an i.v. infusion. The results are considered in relation to the pathophysiology of cholera secretion and to the current views of receptor subtypes for 5-HT. It is proposed that the receptor involved is a 5-HT₃ receptor, possibly also a receptor of the 5-HT₁ type. Results from experiments in which 5-HT (20 mM) was placed in the intestinal lumen to evoke an intestinal secretion suggest that the 5-HT₃ receptor is located in the villus tissue. It was also demonstrated that zimeldine, an inhibitor of presynaptic 5-HT reuptake, diminished choleraic secretion, an effect that may be ascribed to a 5-HT tachyphylaxis caused by an accumulation of 5-HT in a synaptic cleft.