大鼠心内精氨酸血管加压素免疫反应阳性神经元的观察

本文用精氨酸血管加压素抗血清作为第一级抗体,通过石蜡切片免疫组织化学 PAP 法对大鼠心内神经节进行了研究,发现心内不仅存在精氨酸血管加压素免疫反应阳性的神经纤维,而且含有该免疫反应阳性的神经细胞。关于精氨酸血管加压素免疫反应阳性的胞体和纤维在心内存在的生理学意义本文进行了讨论。     

心内神经元血管加压素的基因表达-原位杂交与免疫组织化学结合法研究

取中华蟾蜍心房后壁腔静脉窦部位组织作冰冻切片（30μm）,以原位杂交和免疫组织化学双标法进行心内神经节细胞的血管加压素mRNA(VPmRNA)及血管加压素免疫反应（VP-IR）染色观察,结果在心内神经节发现了3种标记细胞;（1）VP-IR阳性神经元;（2）VPmRNA阳性神经元;（2）VPmRNA和VP-IR双阳性神经元,VPmRNA和VP-IR双标记神经元证明部分心内神经节的细胞元内既有血管加压素（VP）的基因表达,又储存VP,从而说明VP系心内神经节的一种内源性神经递质,为心内神经节以VP为递质直接参与血液循环的调节提供了直接的分子生物学和化学神经解剖学证据。     

Apelin与血管加压素在水平衡中的研究

Apelin受体与血管加压素Ⅱ型受体均属于G蛋白偶联受体,Apelin与血管加压素均由下丘脑大细胞AVP神经元分泌,Apelin受体与血管加压素Ⅱ型受体均在肾脏表达,本文就Apelin与血管加压素的分布及参与水平衡调节做简单的综述,为其参与水代谢疾病的发病机制提供理论依据。     

磁场对丘脑下部一氧化氮含量的影响及与丘脑下部神经内分泌核团的关系

应用硝酸还原酶反应—分光光度法测定和NADPH-d组织化学技术,对磁场处理后丘脑下部一氧化氮量的变化及其可能的原因进行了研究,发现磁场可促使丘脑下部一氧化氮量(OD值)显著升高,并具有显著滞后效应。NADPH-d阳性神经细胞及NADPH-d和血管加压素(AVP)双染阳性神经细胞集中分布在丘脑下部室旁核、室周核和视上核,但不存在 于视交叉上核,提示室旁核、室周核和视上核一氧化氮能神经细胞是丘脑下部的一氧化氮的主要来源。磁场处理后大鼠丘脑下部一氧化氮含量(OD值)较正常对照组显著升高应归因于这些神经细胞受磁场作用表达增强。一氧化氮和血管加压素的共存可能对磁场调节内分泌具有一定意义。     

血管加压素样细胞在腺垂体内的存在

血管加压素样细胞在腺垂体内的存在刘能保张敏海刘少纯李红莲周顺长（同济医科大学基础医学院组织胚胎学教研室,武汉４３００３０）至今的研究证明,合成和释放血管加压素（Ｖａｓｏｐｒｅｓｓｉｎ,ＶＰ）的细胞存在于下丘脑视上核、室旁核、室周区、视交叉上核和某些副...     

从分子水平探索旋转恒定磁场对机体作用之机理

用RCMF旋磁治疗装置研究磁场对信息物质的影响,放射免疫测定发现磁场促使血浆内啡肽显著升高;荧光分光光度法和ELISA法测定发现磁场可以显著抑制5-HT及顺铂等中枢性致呕药物引起的呕吐反应,并同步伴有脑组织、小肠组织5-HT水平的可逆性下降.磁场处理对小鼠5-HT水平的影响表现出明显的窗口效应和滞后效应,磁场对药物致呕的抑制效应与其对5-HT的下调水平有平行相关关系.提示磁场对体内5-HT水平的降低,可能是其抑制细胞毒性化疗药物致呕的内在基础.应用硝酸还原酶反应-分光光度法和NADPH-d组织化学技术,发现磁场可促使丘脑下部一氧化氮(NO)含量显著升高,并具有显著滞后效应. NADPH-d阳性神经细胞及NADPH-d和血管加压素(AVP)双染阳性神经细胞集中分布在丘脑下部室旁核、室周核和视上核,但不存在于视交叉上核,提示室旁核、室周核和视上核一氧化氮肽能神经细胞是丘脑下部的一氧化氮的主要来源.磁场处理后大鼠丘脑下部一氧化氮含量较正常对照组显著升高应归因于这些神经细胞受磁场作用表达增强.一氧化氮和血管加压素的共存可能对磁场调节内分泌具有一定意义.发现磁场可促使肾上腺一氧化氮量显著升高,并维持一定时间,神经肽Y免疫细胞化学染色强度增强,进而对其相关机制和意义进行了讨论.     

加压素在血压调节中的作用

生理范围内的血浆加压素,具有强烈的缩血管作用;但在正常动物,引起血压升高所需的加压素血浆浓度,远远超过最大抗利尿作用所需的浓度。脱水、失血时,加压素对维持动脉血压起重要作用;加压素亦与肾素血管紧张素有互补关系。     

血管内皮细胞转分化诱导

血管内皮细胞(vascular endothelial cell, VEC)作为血管的支架和衬里能维持血管的正常形态和生理功能 ,并通过合成、分泌多种血管活性物质参与调控血管平滑肌细胞的增殖及收缩.研究表明, VEC可以在一定条件下转分化为其它表型的细胞,如平滑肌细胞、神经细胞等,这种转变可能会导致双重的生理学效应,因此越来越受到研究者的关注.     

高肺血流对大鼠肺血管结构及尾加压素Ⅱ表达的影响

目的：探讨新型血管活性肽人类尾加压素Ⅱ(hUⅡ)在高肺血流量所致肺动脉高压大鼠肺动脉中的表达及其作用。方法：对大鼠行腹主动脉-下腔静脉分流术。11周后,以右心导管法测肺动脉压力,观测肺血管显微结构的变化,以免疫组织化学方法检测肺动脉hUⅡ的表达。结果：分流术后11周,大鼠肺动脉高压形成,肺小血管肌化程度明显增强,肺中、小型肌型动脉相对中膜厚度明显增加。分流组大鼠肺动脉内皮细胞和平滑肌细胞hUⅡ蛋白表达上调,并且与肺动脉压力和肺血管结构的改变呈正相关。结论：肺动脉内皮细胞和平滑肌细胞hUⅡ的上调可能参与了高肺血流量所致肺血管结构重建和肺动脉高压的形成。     

不同月龄长爪沙鼠视上核加压素分泌的实验

血管加压素(arginine vasopressin,AVP)是下丘脑视上核和室旁核神经元分泌的九肽激素。关于长爪沙鼠不同月龄加压素的分泌状况少见报道。作者采用光镜和电镜、免疫细胞化学和图像分析技术,对不同月龄长爪沙鼠视上核(SON)加压素能神经元加压素的分泌进行了比较研究。结果表明：在H．E染色切片中,各组均可见视上核团呈三角形。免疫细胞化学标记的各组长爪沙鼠中均可见AVP阳性细胞。图像分析数据经统计学处理表明：成龄长爪沙鼠血管加压素的分泌能力较强,幼龄及老龄组分泌能力减弱。     

Chronic myocardial infarction induces phenotypic and functional remodeling in the guinea pig cardiac plexus

Chronic myocardial infarction (CMI) is associated with remodeling of the ventricle and evokes adaption in the cardiac neurohumoral control systems. To evaluate the remodeling of the intrinsic cardiac nervous system following myocardial infarction, the dorsal descending coronary artery was ligated in the guinea pig heart and the animals were allowed to recover for 7-9 wk. Thereafter, atrial neurons of the intrinsic cardiac plexus were isolated for electrophysiological and immunohistochemical analyses. Intracellular voltage recordings from intrinsic cardiac neurons demonstrated no significant changes in passive membrane properties or action potential configuration compared with age-matched controls and sham-operated animals. The intrinsic cardiac neurons from chronic infarcted hearts did demonstrate an increase in evoked action potential (AP) frequency (as determined by the number of APs produced with depolarizing stimuli) and an increase in responses to exogenously applied histamine compared with sham and age-matched controls. Conversely, pituitary adenylate cyclase-activating polypeptide (PACAP)-induced increases in intrinsic cardiac neuron-evoked AP frequency were similar between control and CMI animals. Immunohistochemical analysis demonstrated a threefold increase in percentage of neurons immunoreactive for neuronal nitric oxide synthase (NOS) in CMI animals compared with control and the additional expression of inducible NOS by some neurons, which was not evident in control animals. Finally, the density of mast cells within the intrinsic cardiac plexus was increased threefold in preparations from CMI animals. These results indicate that CMI induces a differential remodeling of intrinsic cardiac neurons and functional upregulation of neuronal responsiveness to specific neuromodulators.     

Stochastic behavior of atrial and ventricular intrinsic cardiac neurons.

To quantify the concurrent transduction capabilities of spatially distributed intrinsic cardiac neurons, the activities generated by atrial vs. ventricular intrinsic cardiac neurons were recorded simultaneously in 12 anesthetized dogs at baseline and during alterations in the cardiac milieu. Few (3%) identified atrial and ventricular neurons (2 of 72 characterized neurons) responded solely to regional mechanical deformation, doing so in a tightly coupled fashion (cross-correlation coefficient r = 0.63). The remaining (97%) atrial and ventricular neurons transduced multimodal stimuli to display stochastic behavior. Specifically, ventricular chemosensory inputs modified these populations such that they generated no short-term coherence among their activities (cross-correlation coefficient r = 0.21 +/- 0.07). Regional ventricular ischemia activated most atrial and ventricular neurons in a noncoupled fashion. Nicotinic activation of atrial neurons enhanced ventricular neuronal activity. Acute decentralization of the intrinsic cardiac nervous system obtunded its neuron responsiveness to cardiac sensory stimuli. Most atrial and ventricular intrinsic cardiac neurons generate concurrent stochastic activity that is predicated primarily upon their cardiac chemotransduction. As a consequence, they display relative independent short-term (beat-to-beat) control over regional cardiac indexes. Over longer time scales, their functional interdependence is manifest as the result of interganglionic interconnections and descending inputs.     

Distribution of intrinsic cardiac neurons in whole-mount guinea pig atria identified by multiple neurochemical coding

Functional data indicate that neurons in distinct regions of the heart exert preferential regional cardiac control. To date the regional distribution of specific types of neurons within the intrinsic cardiac nervous system remains unknown, as does their associations with distinct neurotransmitter and/or neuromodulatory profiles. This study was designed to ascertain: (1) the distribution of different classes of neurons within the intrinsic cardiac nervous system as determined by microscopic analysis; (2) the neurochemical profiles of neurons in differing atrial loci; (3) which neurochemicals are co-localized within specific populations of intrinsic cardiac neurons; and (4) the distribution of specific sub-populations of neurons expressing specific immunoreactivities. Taking advantage of confocal laser scanning microscopy and distinct immunoreactive fluorescent markers in various double-label combinations, several sub-populations of intrinsic cardiac neurons were identified. Of all identified neurons, 85-90% were located in ganglia (ganglionic neurons), the rest being isolated (individual neurons). The two general neuronal markers protein gene product 9.5 (PGP 9.5) and microtubule-associated protein (MAP-2) were associated with neurons clustered primarily in the interatrial septum and around the origins of the two vena cavae. Ganglia (group 1) contained three sub-populations of neurons: approx. 80% of ganglionic neurons were large (15-40 microm diameters; group 1a) and approx. 20% had smaller diameters (less than 15 microm; group 1b). All of these neurons were PGP-immunoreactive, exhibiting choline acetyltransferase (ChAT) immunoreactivity (IR), tyrosine hydroxylase (TH) IR, neuropeptide Y (NPY) IR, vasoactive peptide (VIP) IR and substance P (SP) IR. The remaining 5% of ganglionic neurons were small (group 1c; less than 20 microm). These displayed TH immunoreactivity but not MAP, PGP, CHAT, NPY or SP immunoreactivity. Ten to fifteen percent of all neurons loosely distributed outside of ganglia were small (10-25 microm) and located primarily around the origin of the superior vena cava. They displayed immunoreactivity to TH, ChAT, VIP, NPY and SP, but not to MAP-2 or PGP 9.5. These data provide anatomical and immunohistochemical evidence for specific localization of differing populations of intrinsic cardiac neurons with respect to their size, ganglionic distributions and capacity to express multiple neurotransmitters. Although the functional importance of such a regional distribution of differing populations of intrinsic cardiac neurons remains unknown, these anatomical data support the thesis that unique clustering of specific populations of neurons within this nervous system represents the anatomical substrate for complex local cardiac regulatory phenomena occurring at the level of the target organ.     

Function of human intrinsic cardiac neurons in situ

We sought to determine the behavior of intrinsic cardiac neurons in human subjects undergoing cardiac surgery and to correlate their activity with hemodynamics status. A lead II electrocardiogram, pulmonary artery pressure, and systemic arterial pressure were recorded along with extracellular activity generated by right atrial neurons in 10 patients undergoing coronary artery bypass surgery. Identified neurons generated spontaneously activity that was, for the most part, unrelated to the cardiac cycle. Most neurons were activated by gentle mechanical distortion of ventricular epicardial loci. The activity generated by neurons in each patient increased when arterial pressure increased and decreased when arterial pressure fell. Intrinsic cardiac neurons continued to generate activity during cardioplegia and cardiopulmonary bypass, but at reduced levels. Normal neuronal activity was restored postbypass. It is concluded that human intrinsic cardiac neurons generate spontaneous activity and that many receive inputs from ventricular mechanosensory neurites. The latter may account for the fact that their behavior depends, in part, on cardiac dynamics. They are also sensitive to intravenously administered pharmacological agents. These data also indicate that cardiopulmonary bypass and cardioplegia do not induce residual depression of their function.     

Presence and co-localization of vasoactive intestinal polypeptide with neuronal nitric oxide synthase in cells and nerve fibers within guinea pig intrinsic cardiac ganglia and cardiac tissue

The presence of vasoactive intestinal polypeptide (VIP) has been analyzed in fibers and neurons within the guinea pig intrinsic cardiac ganglia and in fibers innervating cardiac tissues. In whole-mount preparations, VIP-immunoreactive (IR) fibers were present in about 70% of the cardiac ganglia. VIP was co-localized with neuronal nitric oxide synthase (nNOS) in fibers innervating the intrinsic ganglia but was not present in fibers immunoreactive for pituitary adenylate cyclase-activating polypeptide, choline acetyltransferase (ChAT), tyrosine hydroxylase, or substance P. A small number of the intrinsic ChAT-IR cardiac ganglia neurons (approximately 3%) exhibited VIP immunoreactivity. These few VIP-IR cardiac neurons also exhibited nNOS immunoreactivity. After explant culture for 72 h, the intraganglionic VIP-IR fibers degenerated, indicating that they were axons of neurons located outside the heart. In cardiac tissue sections, VIP-IR fibers were present primarily in the atria and in perivascular connective tissue, with the overall abundance being low. VIP-IR fibers were notably sparse in the sinus node and conducting system and generally absent in the ventricular myocardium. Virtually all VIP-IR fibers in tissue sections exhibited immunoreactivity to nNOS. A few VIP-IR fibers, primarily those located within the atrial myocardium, were immunoreactive for both nNOS and ChAT indicating they were derived from intrinsic cardiac neurons. We suggest that, in the guinea pig, the majority of intraganglionic and cardiac tissue VIP-IR fibers originate outside of the heart. These extrinsic VIP-IR fibers are also immunoreactive for nNOS and therefore most likely are a component of the afferent fibers derived from the vagal sensory ganglia. This work was supported by NIH grant HL65481 (R.L.P.) and HL54633 (D.B.H.). Use of the DeltaVision Restoration microscope was provided through the Imaging/Physiology Core supported by NIH Grant P20 RR16435 from the COBRE program of the National Center for Research Resources     

化学损毁交感神经后大鼠心内神经节生长抑素的变化

应用免疫组织化学和原位杂交方法研究了大鼠心内神经节细胞中SS的分布及其mRNA表达。结果发现,大鼠心内神经节中有SS－IR阳性神经纤维和细胞,心内神经部分细胞浆中有SSmRNA表达,表明大鼠心内神经节细胞有SS合成和贮存。用小剂量6－OH－DA选择性损毁心内交感神经纤维后,心内神经节中SS－IR阳性神经纤维和细胞的积分光密度均有不同程度增强,反映了心内交感神经和付交感神经的相互抑制作用。     

Intrinsic cardiac nervous system in tachycardia induced heart failure

The purpose of this study was to test the hypothesis that early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiac function. After 2 wk of rapid ventricular pacing in nine anesthetized canines, cardiac and right atrial neuronal function were evaluated in situ in response to enhanced cardiac sensory inputs, stimulation of extracardiac autonomic efferent neuronal inputs, and close coronary arterial administration of neurochemicals that included nicotine. Right atrial neuronal intracellular electrophysiological properties were then evaluated in vitro in response to synaptic activation and nicotine. Intrinsic cardiac nicotine-sensitive, neuronally induced cardiac responses were also evaluated in eight sham-operated, unpaced animals. Two weeks of rapid ventricular pacing reduced the cardiac index by 54%. Intrinsic cardiac neurons of paced hearts maintained their cardiac mechano- and chemosensory transduction properties in vivo. They also responded normally to sympathetic and parasympathetic preganglionic efferent neuronal inputs, as well as to locally administered alpha-or beta-adrenergic agonists or angiotensin II. The dose of nicotine needed to modify intrinsic cardiac neurons was 50 times greater in failure compared with normal preparations. That dose failed to alter monitored cardiovascular indexes in failing preparations. Phasic and accommodating neurons identified in vitro displayed altered intracellular membrane properties compared with control, including decreased membrane resistance, indicative of reduced excitability. Early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiodynamics. While maintaining its capacity to transduce cardiac mechano- and chemosensory inputs, as well as inputs from extracardiac autonomic efferent neurons, intrinsic cardiac nicotine-sensitive, local-circuit neurons differentially remodel such that their capacity to influence cardiodynamics becomes obtunded.     

大鼠心内神经元至颈上神经节的分支投射研究

应用CB－HRP逆行追踪法研究了大鼠心内神经元至颈上神经节的分支投射。将CB－HRP注入大鼠颈上神经节内,在心脏壁内神经节见到CB－HRP标记细胞,这些细胞为中小型梭形或园形,多位于心房后壁。结果表明心内神经元有分支投射到颈上神经节,并对此进行了讨论。     

Effects of chronic cardiac decentralization on functional properties of canine intracardiac neurons in vitro

Although intrinsic cardiac neurons display ongoing activity after chronic interruption of extrinsic autonomic inputs to the heart, the effects of decentralization on individual neurons remain unknown. The objective of this study was to determine the effects of chronic (3-4 wk) surgical decentralization on intracellular properties of, and neurotransmission among, neurons contained within the canine intrinsic right atrial ganglionated plexus in vitro. Properties of neurons from decentralized hearts were compared with those of neurons from sham-operated hearts (controls). Two populations of neurons were identified by their firing behavior in response to intracellular current injection. Fifty-nine percent of control neurons and 72% of decentralized neurons were phasic (discharged one action potential on excitation). Forty-one percent of control neurons and 27% of decentralized neurons were accommodating (multiple discharge with decrementing frequency). After chronic decentralization, input resistance of phasic neurons increased, whereas the duration of afterhyperpolarization of accommodating neurons decreased. Postsynaptic responses to interganglionic nerve stimulation were evoked in 89% of control neurons and 83% of decentralized neurons; the majority of these responses involved nicotinic receptors. These results show that, after chronic decentralization, intrinsic cardiac neurons 1) undergo changes in membrane properties that may lead to increased excitability while 2) maintaining synaptic neurotransmission within the intrinsic cardiac ganglionated plexus.     

Chronic decentralization of the heart differentially remodels canine intrinsic cardiac neuron muscarinic receptors

The objective of the study was to determine if chronic interruption of all extrinsic nerve inputs to the heart alters cholinergic-mediated responses within the intrinsic cardiac nervous system (ICN). Extracardiac nerve inputs to the ICN were surgically interrupted (ICN decentralized). Three weeks later, the intrinsic cardiac right atrial ganglionated plexus (RAGP) was removed and intrinsic cardiac neuronal responses were evaluated electrophysiologically. Cholinergic receptor abundance was evaluated using autoradiography. In sham controls and chronic decentralized ICN ganglia, neuronal postsynaptic responses were mediated by acetylcholine, acting at nicotinic and muscarinic receptors. Muscarine- but not nicotine-mediated synaptic responses that were enhanced after chronic ICN decentralization. After chronic decentralization, muscarine facilitation of orthodromic neuronal activation increased. Receptor autoradiography demonstrated that nicotinic and muscarinic receptor density associated with the RAGP was unaffected by decentralization and that muscarinic receptors were tenfold more abundant than nicotinic receptors in the right atrial ganglia in each group. After chronic decentralization of the ICN, intrinsic cardiac neurons remain viable and responsive to cholinergic synaptic inputs. Enhanced muscarinic responsiveness of intrinsic cardiac neurons occurs without changes in receptor abundance.