Cerebral type 2 astroglia are heterogeneous with respect to their ability to respond to neuroligands linked to calcium mobilization.     

V Dave  G W Gordon  K D McCarthy 《Glia》1991,4(5):440-447

Very little information is available concerning the pharmacology of type 2 astroglia. During the past decade it has become apparent that two distinct lineages of astroglial cells can be defined in vitro. These two lineages are commonly referred to as type 1 and type 2 and are distinguished from each other on the basis of their morphological features and antigenic phenotypes. In contrast to type 1 astroglia, very little is known about the pharmacology of type 2 astroglia. The lack of information concerning the responsiveness of these cells stems primarily from difficulties encountered in isolating large numbers of type 2 astroglia free of other cell types. In the present study video- and photometer-based imaging systems were used to monitor the influence of a series of neuroligands on the intracellular calcium levels of individual cerebral type 2 astroglia in order to assess their expression of calcium-mobilizing receptors. The responses of 85 immunocytochemically identified cerebral type 2 astroglia to bradykinin (BK), norepinephrine (NE), histamine (HIST), carbachol (CARB), 2-methyl-thio ATP (2MT-ATP), glutamate (GLUT), and serotonin (5-HT) were analyzed. Approximately 50% of cerebral type 2 astroglia responded to BK, NE, HIST, CARB, and 2MT-ATP whereas only 16% and 9% of the cells responded to GLUT and 5-HT, respectively. The number of neuroligands that increased calcium in individual cells ranged from 0 to 6. These responses are quite similar to those previously demonstrated in cultured cerebral type 1 astroglia. No pattern of receptor co-expression was observed for the different neuroligands tests.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Hypothermia decreases excitatory neurotransmitter release in bacterial meningitis in rabbits     

Irazuzta JE  Olson J  Kiefaber MP  Wong H 《Brain research》1999,847(1):325-148

The excitatory neurotransmitters glutamate (GLU) and aspartate (ASP) are involved in the pathogenesis of neuronal injury in meningitis. Based on past findings that the induction of moderate hypothermia (32-34 degrees C) attenuates the release of GLU in ischemic brain injury, this study was designed to detect if the application of moderate hypothermia decreases the release of excitatory amino acids (EAA) from brain tissue of animals with bacterial meningitis. Also examined was whether meningitis induces the expression of 72-kDa heat shock protein (HSP 70) in the cerebellum and how hypothermia affects it, for induction of HSP 70 has been used as a sensitive marker of neuronal stress in other forms of brain injury. Meningitis was induced by injecting Group B Streptococcus (GBS) into the cisterna magnae of rabbits. Antibiotic treatment began 16 h later. At this time the animals were anesthetized, instrumented, and randomized to normothermic (Nor) or hypothermic (Hy) conditions. Temperatures were strictly regimented for the following 10 h while maintaining stable cardiorespiratory parameters. Cerebrospinal fluid (CSF) samples were then withdrawn to measure concentrations of bacteria, protein, and amino acids. Meningitis causes CSF contents of GLU and ASP to increase significantly. Hypothermia treated animals demonstrated a 40-50% reduction in CSF GLU and ASP. Meningitis induced the expression of HSP 70 in the cerebellum while hypothermic animals experienced a significant decrease HSP 70 induction. These data demonstrate that hypothermia produces an attenuation of the release of excitatory neurotransmitters in meningitis and suggest that this treatment may attenuate neuronal stress.  相似文献   

In vivo release of neuronal histamine in the hypothalamus of rats measured by microdialysis     

T. Mochizuki  A. Yamatodani  K. Okakura  M. Takemura  N. Inagaki  H. Wada 《Naunyn-Schmiedeberg's archives of pharmacology》1991,343(2):190-195

Summary Using an in vivo intracerebral microdialysis method coupled with an HPLC-fluorometric method, we investigated the extracellular level of endogenous histamine in the anterior hypothalamic area of urethaneanaesthetized rats. The basal rate of release of endogenous histamine in the anterior hypothalamic area measured by this method was 0.09 + 0.01 pmol/20 min. When the anterior hypothalamic area was depolarized by infusion of 100 mM K⁺ through the dialysis membrane or electrical stimulation at 200 A was applied through an electrode implanted into the ipsilateral tuberomammillary nucleus, histamine release increased to 175% and 188%, respectively, of the basal level. These increases were completely suppressed by removal of extracellular Ca²⁺. The basal release of histamine was also suppressed after infusion of 10^–6 M tetrodotoxin or i.p. administration of 100 mg/kg of -fluoromethylhistidine. On the other hand, 3-fold increase in the basal release was observed after i. p. administration of 5 mg/kg thioperamide. These results clearly indicate that both the basal and evoked release of histamine measured by our method are of neuronal origin. Send offprint requests to T. Mochizuki at the above address  相似文献   

胆管癌周围神经浸润的研究进展     

冯玉杰  张炳远  卢云 《国际外科学杂志》2010,37(7)

胆管癌是一种破坏力极强的恶性肿瘤,具有低诊断率和高病死率的特点,手术是其唯一的根治方法,然而患者就诊往往在进展期,所以目前胆管癌的根治率很低,且手术复发率很高.胆管癌沿周围神经浸润是胆管癌发生发展过程中特别是在早期具有的非常重要的特性,且与术后复发率和预后密切相关.因此,如果了解胆管癌周围神经浸润的相关机制,早期对其进行干预,必将大大提高患者的手术切除率及预后.本文重点就目前胆管癌神经浸润研究最热门的几个可能的分子及其可能的相关机制进行综述.  相似文献   

针刺对血管性痴呆大鼠行为及脑内神经递质的影响     

唐明  杨秀丽  王莉  李晓昱 《世界中西医结合杂志》2007,2(6):338-340

目的:观察针刺治疗对于血管性痴呆大鼠学习记忆行为及脑内神经递质的影响。方法:制备120只VD大鼠模型,随机分组后给予药物和/或针刺治疗,针刺取主穴肾俞、肝俞、脾俞、百会、四神聪、神庭、水沟、内关、风池,每日1次,每次30min,10d为1个疗程,共进行3个疗程,疗程间休息1d。治疗前后采用迷宫实验与跳台实验进行行为学观测,行为学观测后将大鼠处死,检测脑组织中神经递质的含量。结果:各治疗组VD大鼠的学习与记忆能力较治疗前有明显提高,VD大鼠脑组织中相关递质含量较正常对照组降低,经过30d治疗后递质有不同程度的提高,针药组的行为改善与递质升高均优于针刺组与药物组,而针刺组又优于药物组。结论:针刺治疗能明显改善VD大鼠的认知功能,而且能够改善Ach、5-HT、CAs等神经递质的功能状态;针刺治疗较抗痴呆药物单一应用有一定优势,不但效果较好,且与传统抗痴呆药物有协同作用,能够加强药物的疗效。  相似文献   

同性恋者及其性取向的生物学研究进展     

李慧  杨裕华  屠爱霞 《中国性科学》2013,(11):97-100,107

本文就近些年来有关同性恋的性取向及其影响因素的研究进展做一综述,旨在不仅以心理学角度关心同性恋者,更重要的是从遗传学、神经生物学方面揭示同性恋的成因,以使其得到社会的理解和认同,创造宽松和谐的环境,使他们不再感到孤独.  相似文献   

T-type channels-secretion coupling: evidence for a fast low-threshold exocytosis     

Carbone E  Marcantoni A  Giancippoli A  Guido D  Carabelli V 《Pflügers Archiv : European journal of physiology》2006,453(3):373-383

T-type channels are transient low-voltage-activated (LVA) Ca²⁺ channels that control Ca²⁺ entry in excitable cells during small depolarizations around resting potential. Studies in the past 20 years focused on the biophysical, physiological, and molecular characterization of T-type channels in most tissues. This led to a well-defined picture of the functional role of LVA channels in controlling low-threshold spikes, oscillatory cell activity, muscle contraction, hormone release, cell growth and differentiation. So far, little attention has been devoted to the role of T-type channels in transmitter release, which mainly involves channel types belonging to the high-voltage-activated (HVA) Ca²⁺ channel family. However, evidence is accumulating in favor of a unique participation of T-type channels in fast transmitter release. Clear data are now reported in reciprocal synapses of the retina and olfactory bulb, synaptic contacts between primary afferent and second order nociceptive neurons, rhythmic inhibitory interneurons of invertebrates and clonal cell lines transfected with recombinant α₁ channel subunits. T-type channels also regulate the large dense-core vesicle release of neuroendocrine cells where Ca²⁺ dependence, rate of vesicle release, and size of readily releasable pool appear comparable to those associated to HVA channels. This suggests that when sufficiently expressed and properly located near the release zones, T-type channels can trigger fast low-threshold secretion. In this study, we will review the main findings that assign a specific task to T-type channels in fast exocytosis, discussing their possible involvement in the control of the Ca²⁺-dependent processes regulating exocytosis like vesicle depletion and vesicle recycling.  相似文献   

左归丸、右归丸对老年大鼠海马、杏仁核氨基酸类和单胺类神经递质含量变化的影响   总被引：2，自引：2，他引：2  

戴薇薇  金国琴  张学礼  姚领爱  徐品初 《中国老年学杂志》2006,26(8):1066-1069

目的 观察左归丸、右归丸对老年大鼠海马、杏仁核氨基酸类神经递质Asp、Glu、Gly、GABA和单胺类神经递质5-HT、NE含量变化的影响，探讨老年机体神经元的神经递质的变化，以及左归丸、右归丸延缓老年大鼠神经内分泌调控退化的作用机制。方法 以自然衰老大鼠为动物模型，分设4组：青年对照组、老年对照组、老年左归丸组、老年右归丸组。采用HPLC-荧光法，检测各组大鼠海马、杏仁核Asp、Glu、gly、GABA含量变化；采用ELISA法，检测5-HT、NE含量变化。结果 与青年对照组相比，老年对照组大鼠海马、杏仁核Asp、Glu、Gly、GABA含量有不同程度升高，而与老年对照组相比，两用药组含量有不同程度降低。同时，老年对照组大鼠海马NE含量减少，左归丸组能提高老年大鼠海马NE含量。而各组大鼠5-HT含量无明显差异。结论 左归丸、右归丸通过不同程度地纠正老年大鼠海马和杏仁核脑区氨基酸类和单胺类神经递质的紊乱状态，使兴奋性和抑制性神经递质趋向平衡，从而有助于改善大脑边缘系统，延缓机体衰老。  相似文献   

Regulation of GABA release by depolarisation-evoked Ca2+ transients at a single hippocampal terminal     

Fedulova SA  Verkhratsky A  Veselovsky NS 《Pflügers Archiv : European journal of physiology》2004,448(4):376-382

We correlated dynamic changes in free cytosolic [Ca²⁺] ([Ca²⁺]_i) within single presynaptic terminals of cultured hippocampal neurones with the postsynaptic GABA-mediated currents. The local changes in [Ca²⁺]_i and evoked inhibitory postsynaptic currents (eIPSCs) were recorded simultaneously using Fura-2 fluorescence and whole-cell patch-clamp respectively. The Ca²⁺ signals and eIPSCs were evoked by direct extracellular electrical stimulation of a single presynaptic terminal by short depolarising pulses. The presynaptic Ca²⁺ transient was graded by varying the amplitude of extracellular stimulating pulses. The probability of the release event, P, estimated for each stimulation strength, reached a maximum (P=1) when the Ca²⁺ signal became maximal and remained at this level at higher stimulation strength, despite the subsequent decrease in the amplitude of the Ca²⁺ transient. A gradual, linear increase in stimulation amplitude (V_stim) resulted in a bell-shaped dependence of the averaged amplitudes of Ca²⁺ signals and corresponding averaged amplitudes of eIPSCs. Analysis of the eIPSC demonstrated that the decrease in both the mean eIPSC amplitude and the mean quantal content of release resulted from a reduction in the probability of multivesicular release, i.e. in the disappearance of failures and in the decrease of individual eIPSC amplitude. The Ca²⁺ signals of similar amplitude resulted in both random and determinate (non-random) neurotransmitter release. We conclude that depolarisation-induced elevation of [Ca²⁺]_i within the terminal is necessary but not sufficient for activation of vesicular release of neurotransmitter.  相似文献   

高效液相色谱法快速测定氨基酸类神经递质     

黄晓  康学军  肖静  杨鹏  李涛 《上海医学检验杂志》2006,(3)

目的建立一种同时快速测定大鼠纹状体中谷氨酸(G lu)、天冬氨酸(Asp)、γ-氨基丁酸(GABA)、甘氨酸(G ly)、牛磺酸(Tau)5种氨基酸类神经递质的高效液相色谱法。方法采用Krom asil C18(4.6×250 mm,5μm)为色谱柱,丹酰氯为柱前衍生试剂,以曲唑酮为内标,以0.1 mol/L醋酸钠缓冲液∶甲醇=58∶42、14 mmol/L庚烷磺酸钠为流动相等度洗脱。结果在1~200 mg/L范围内,各组分线性关系良好(r=0.999)。各氨基酸的平均回收率为79.1%~92.9%。结论本方法简便、快速、准确,可用于临床大样本测定和研究神经及精神疾病氨基酸类神经递质的改变。  相似文献