Chronic opioid treatment of neuroblastoma X dorsal root ganglion neuron hybrid F11 cells results in elevated GM1 ganglioside and cyclic adenosine monophosphate levels and onset of naloxone-evoked decreases in membrane K+ currents     

G. Wu  S. F. Fan  Z.-H. Lu  R. W. Ledeen  S. M. Crain 《Journal of neuroscience research》1995,42(4):493-503

Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via G_s regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K⁺ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the G_s/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc.  相似文献   

THE CONTROL OF HUMAN MOTOR UNITS     

Timothy S. Miles 《Clinical and experimental pharmacology & physiology》1994,21(7):511-520

1. The motor unit, consisting of a single motor neuron and the skeletal muscle fibres that it innervates, is the final output pathway of the motor system. 2. Much is now known about the way that human motor neurons are recruited and controlled during voluntary and reflex movements. This review briefly summarizes some of the recent experimental data that has contributed to our present understanding. The review is largely limited to data obtained in human experiments. While much of what we know about the organization of the nervous system has come from studies of the anatomy and physiology of experimental animals, there are some questions that cannot be addressed in reduced animal preparations. The development of new techniques has made it possible to investigate the human nervous system at a level of detail that has not hitherto been possible.  相似文献   

Microtubule dynamics in axons and dendrites.   总被引：9，自引：0，他引：9  

P W Baas  T Slaughter  A Brown  M M Black 《Journal of neuroscience research》1991,30(1):134-153

We have investigated the stability, alpha-tubulin composition, and polarity orientation of microtubules (MTs) in the axons and dendrites of cultured sympathetic neurons. MT stability was evaluated in terms of sensitivity to nocodazole, a potent anti-MT drug. Nocodazole sensitivity was assayed by quantifying the loss of MT polymer as a function of time in 2 micrograms/ml of the drug. MTs in the axon and the dendrite exhibit striking similarities in their drug sensitivity. In both types of neurites, the kinetics of MT loss are biphasic, and are consistent with the existence of two types of MT polymer that depolymerize with half-times of MT polymer that depolymerize with half-times of approximately 3.5 min and approximately 130 min. We define the more rapidly depolymerizing polymer as drug-labile and the more slowly depolymerizing polymer as drug-stable. The proportion of MT polymer that is drug-stable is greater in axons (58%) than in dendrites (25%). On the basis of current understanding of the mechanism of action of nocodazole, we suggest that the drug-labile and drug-stable polymer observed in both axons and dendrites correspond to two distinct types of polymer that differ in their relative rates of turnover in vivo. In a previous study, we established that in the axon, these drug-stable and drug-labile types of MT polymer exist in the form of distinct domains on individual MTs, with the labile domain situated at the plus end of the stable domain (Baas and Black, J Cell Biol 111:495-509, 1990). Because of the great difference in drug sensitivity between the drug-labile and drug-stable MT polymer, we were able to dissect them apart by appropriate treatments with nocodazole. This permitted us to evaluate the drug-labile and drug-stable polymer in terms of polarity orientation and relative content of alpha-tubulin variants generated by posttranslational detyrosination or acetylation. In both the axon and the dendrite, the modified as well as unmodified alpha-tubulins are present in both drug-labile and drug-stable polymer, but at different levels. Specifically, the modified forms of alpha-tubulin are enriched in the drug-stable MT polymer compared to the drug-labile MT polymer. In studies on MT polarity orientation, we demonstrate that in axons, MTs are uniformly plus-end-distal, whereas in dendrites, MTs are non uniform in their polarity orientation, with roughly equal levels of the MTs having each orientation.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

Acetylcholine produces stimulus-specific receptive field alterations in cat auditory cortex     

Raju Metherato  Norman M. Weinberger 《Brain research》1989,480(1-2):372-377

Frequency receptive fields (RFs) were determined before and after pairing iontophorectic administration of acetylcholine (ACh) with a repeated single-frequency stimulus in the auditory cortex of barbiturate-anesthesized cats. In 58% of the cells, the paired ACh + tone treatment produced subsequent alterations of frequency RFs. In half of these cases, the RF modifications were highly specific to the frequency that had been paired with ACh. Atropine antagoized the frequency-effects of ACh, suggesting that they were mediated via muscarinic cholinergic receptors.  相似文献   

Neuronal precursors within the adult rat subventricular zone differentiate into dopaminergic neurons following subtantia nigra lesion and chromaffin cell transplant     

O. Arias-Carrin  R. Drucker-Colín 《International journal of developmental neuroscience》2006,24(8):499-500

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大鼠胼胝体神经元化学性质研究:Ⅰ.谷氨酸的免疫细胞化学研究     

丁松林  郑德枢 《广州医学院学报》1990,(3)

采用辣根过氧化物酶(HRP)逆行示踪与谷氨酸免疫细胞化学结合法对大鼠额叶和枕叶皮质内胼胝体神经元的化学性质进行了研究.结果发现含谷氨酸的胼胝体神经元为大中型锥体细胞,主要分布于皮质Ⅱ/Ⅲ、Ⅴ和Ⅵ层,并有成群分布的倾向.含谷氨酸的胼胝体神经元的数目约占 HRP 标记的胼胝体神经元的17%(额叶)和29%(枕叶).这一结果从形态学上证实,大鼠大脑皮质内相当一部分胼胝体神经元使用谷氨酸作为兴奋性递质。  相似文献   

刺激强度对黑质DA能神经元伤害性反应的影响     

高东明  孙德玉 《辽宁医学院学报》1990,11(2):84-89

本研究用细胞外记录方法研究大鼠黑质多巴胺能神经元伤害性反应的特点。共记录了194个多巴胺能神经元。其中,大多数神经元(78％)可被尾部强电刺激(15mA,1.0ms)所抑制,15％被兴奋。兴奋和抑制反应均依赖于刺激强度。当刺激强度变化于0～20mA时,伤害性反应强度与刺激强度的对数显著相关。来自不同部位的刺激可会聚于同一神经元。反应潜伏期和阈值提示Aδ纤维参与伤害性信息传入黑质的过程。本文还讨论了多巴胺能神经元系统在痛觉机制中的作用。  相似文献   

Cholinergic neurons contain Calbindin-D_28k in the monkey medial septal nucleus and nucleus of the diagonal band: an immunocytochemical study     

Yukio Ichitani  Masaki Tanaka  Hitoshi Okamura  Yasuhiko Ibata 《Brain research》1993,625(2)

The distribution patterns of choline acetyltransferase (CAT), as a marker for cholinergic neurons, and Calbindin-D_28k (CaBP) immunoreactivities in the forebrain basal ganglia of the Japanese monkeyMacaca fuscata were compared. Similar distribution patterns of CAT and CaBP immunoreactivities were found in the medial septal nucleus (MS) and the nucleus of the diagonal band of Broca (DBB). Double-labeling fluorescence immunocytochemistry revealed that most, but not all, cholinergic neurons were CaBP-immunoreactive in the MS and DBB. The results suggest that CaBP may play a role in the septohippocampal cholinergic neuron system of the monkey.  相似文献   

大鼠颌下腺、舌下腺副交感节前神经元胞体及树突的研究     

李月奎  李淑芬 《解剖学杂志》1991,(3)

将类霍乱毒素B原结合的辣根过氧化物酶(CB-HRP)注入大鼠一侧颌、舌下腺,标记了脑干内支配该腺副交感节前神经元的胞体及其轴、树突。在光学显微镜下,对所标神经元的位置、胞体形态、大小、树突的分布以及轴突在脑干内的行程做了较为系统的观察和测量,并结合有关参数的相关分析,对泌涎神经元的某些生理学特性做了初步探讨。  相似文献   

Changes in glutamate dehydrogenase activity in ganglion nodosum neurons in rabbits with acute experimental emotional stress     

V. D. Goncharuk 《Bulletin of experimental biology and medicine》1981,92(4):1443-1446

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