神经内分泌和免疫系统之间的相互调节作用(一)

我们一般认为机体各器官、系统的功能都处于神经系统和内分泌系统的调节和控制之下。神经系统和内分泌系统是机体内起主导作用的调节系统。它们密切联系 ,互相配合 ,维持内环境相对稳定。这一传统的观念近年来受到了挑战。新的观点认为 ,免疫系统也是机体内一个重要感受和调节系统。神经内分泌和免疫系统之间的相互作用 ,对机体在不同条件下稳态的维持起有决定性的作用。因此 ,在谈到机体的功能调节时 ,如果不谈免疫系统的作用 ,将是一种缺陷。目前这方面的研究已经发展成为一门独立的边缘学科 :神经免疫调节学、神经免疫内分泌学或神经免疫…     

Experimental evidence for simultaneous existence of two dominantas in the central nervous system

For the first time a possibility of simultaneous existence of two dominants was demonstrated: the polarization in the cortical representation of the forelimb and the dominanta of hunger. The two foci of stable excitation were created at the subthreshold level. A sound stimulus simultaneously produced a movement of the forelimb and a gulp. Manifestation of the two dominantas could be observed over the course of the experiment (about 1 h).     

Excitatory amino acid receptors and synaptic excitation in the mammalian central nervous system.

At least two different types of excitatory amino acid receptors have been identified in the mammalian and amphibian central nervous systems. One type ('NMDA receptors') appears to be important in amino acid-mediated synaptic excitation, NMDA being the most potent and specific exogenous agonist for this type of receptor. Many antagonists have selective blocking actions at these NMDA receptors, and such substances are also selective antagonists of synaptic excitation in the vertebrate spinal cord. It is proposed that these receptors are transmitter receptors activated by an excitatory amino acid. In addition, extrasynaptic receptors, activated by domoate, kainate, quisqualate and L-glutamate, but not by NMDA, and only weakly by L-aspartate, have been identified on dorsal root fibres of the immature rat.     

Interactions between taurine and ethanol in the central nervous system

Summary.  This purpose of this review will be to summarize the interactions between the endogenous amino acid taurine and ethyl alcohol (ethanol) in the central nervous system (CNS). Taurine is one of the most abundant amino acids in the CNS and plays an integral role in physiological processes such as osmoregulation, neuroprotection and neuromodulation. Both taurine and ethanol exert positive allosteric modulatory effects on neuronal ligand-gated chloride channels (i.e., GABA_A and glycine receptors) as well as inhibitory effects on other ligand- and voltage-gated cation channels (i.e., NMDA and Ca²⁺ channels). Behavioral evidence suggests that taurine can alter the locomotor stimulatory, sedating, and motivational effects of ethanol in a strongly dose-dependent manner. Microdialysis studies have revealed that ethanol elevates extracellular levels of taurine in numerous brain regions, although the functional consequences of this phenomenon are currently unknown. Finally, taurine and several related molecules including the homotaurine derivative acamprosate (calcium acetylhomotaurinate) can reduce ethanol self-administration and relapse to drinking in both animals and humans. Taken together, these data suggest that the endogenous taurine system may be an important modulator of effects of ethanol on the nervous system, and may represent a novel therapeutic avenue for the development of medications to treat alcohol abuse and alcoholism. Received November 21, 2001 Accepted January 4, 2002 Published online August 20, 2002 Acknowledgements This work was supported by funds from the State of California for medical research on alcohol and substance abuse through the University of California at San Francisco. The author wishes to thank Drs. C. W. Hodge and P. H. Janak for their support and helpful discussions. Author's address: Dr. M. Foster Olive, Ernest Gallo Clinic and Research Center, Department of Neurology, University of California at San Francisco, 5858 Horton Street, Suite 200, Emeryville, California, U.S.A., Fax +1/510/985 3101, E-mail: folive@itsa.ucsf.edu     

Spiroplasma from Tabanidae capable to multiply and to persist in the central nervous system in mice]

Using alternate passages of cultivation in vitro at 37 degrees C and in suckling mice following intracerebral inoculation, a tabanid spiroplasma was demonstrated capable of multiplication and persistence in mice for 6 successive passages, without production of specific antibody. This is the first report of a spiroplasma from a common flying haematophagous arthropod shown to produce persistent infection of a mammal.     

Primary central nervous system angiosarcoma: two case reports

ABSTRACT: INTRODUCTION: Primary angiosarcoma of the brain is extremely rare; only 15 cases have been reported inadults over the last 25 years.Case presentationsWe describe two cases of primary angiosarcoma of the brain that are well characterized byimaging, histopathology, and immunohistochemistry. Case 1: our first patient was a 35-yearoldwoman who developed exophthalmos. Subtotal resection of a left extra-axial retro-orbitalmass was performed. Case 2: our second patient was a 47-year-old man who presented to ourfacility with acute visual loss, word-finding difficulty and subtle memory loss. Aheterogeneously-enhancing left sphenoid wing mass was removed. We also review theliterature aiming at developing a rational approach to diagnosis and treatment, given the rarityof this entity. CONCLUSIONS: Gross total resection is the standard of care for primary angiosarcoma of the brain. Adjuvantradiation and chemotherapy are playing increasingly recognized roles in the therapy of theserare tumors.     

神经内分泌和免疫系统之间的相互作用(二)——神经免疫调节

(上接 2 0 0 0年第 3期第 3页 )1 .6.2　某些前激素 (prohormone)的作用　血液循环中的硫酸表甾酮 (dehydroepiandrosteronesulphate,DHEAS)受到 DHEA硫酸酶的作用变成 DHEA可增强 TH1的活性 ,此时 TH1/TH2 的比值趋向于 TH1占优势。随着年龄的增加 DHEA的水平也随之下降。这可能是机体随着年龄的增长免疫功能下降的重要原因之一。动物实验中也发现 ,老年鼠体内的 DHEA含量明显低于对照组。如果补充 DHEA后老年鼠的免疫缺损状态可以得到明显改善。此外 ,衰老时的免疫功能下降也与某些细胞因子分泌异常增高有关。例如 IL -6的…     

Mathematical biophysics of sustained nonperiodic oscillations of excitation and inhibition in the central nervous system

There are a number of phenomena in the central nervous system which are not periodic in the strict sense of the word. The simplest example is the α-rhythm which represents an oscillation that is not strictly periodic in a mathematical sense. Some diseases like periodic relapsing catatonia or the manic-depressive psychoses are almost strictly periodical but such phenomena as attacks of epilepsy repeat themselves perhaps at average intervals but those intervals are not equal and are not predictable. We consider that even such phenomena like a fit of creative work has the same mechanism. All those phenomena deal with sporadic spontaneous nonperiodic overexcitation of certain parts of the brain. Depending on which part of the brain is overexcited, we might have either a grand or a petit mal epilepsy, or a fit of creativity. This paper gives a model of two neuronic circuits which can produce nonperiodic spontaneous overexcitation of the cortex. That part of the cortex which happens to have the lowest threshold will be most strongly affected. The location of such parts of the cortex vary from person to person. The paper does not in any way imply that the mechanism described here is responsible for all types of epilepsy. Many of them may have an entirely different origin. The paper does, however, contain a suggestion for an actual cure of some types of epilepsy, which is different from the symptomatic treatment mostly used so far.     

Serotonin-like immunoreactivity in the central nervous system of two ixodid tick species

Immunocytochemistry was used to describe the distribution of serotonin-like immunoreactive (5HT-IR) neurons and neuronal processes in the central nervous system (CNS), the synganglion, of two ixodid tick species; the winter tick, Dermacentor albipictus and the lone star tick, Amblyomma americanum. 5HT-IR neurons were identified in the synganglion of both tick species. D. albipictus had a significantly higher number of 5HT-IR neurons than A. americanum. The labeling pattern and number of 5HT-IR neurons were significantly different between sexes in D. albipictus, but were not significantly different between sexes in A. americanum. 5HT-IR neurons that were located in the cortex of the synganglion projected processes into the neuropils, invading neuromeres in the supraesophageal ganglion including the protocerebrum, postero-dorsal, antero-dorsal and cheliceral neuromeres. In the subesophageal ganglion, dense 5HT-IR neuronal processes were found in the olfactory lobes, pedal, and opisthosomal neuromeres. Double-labeling with neurobiotin backfilled from the first leg damaged at the Haller’s organ revealed serotoninergic neuronal processes surrounding the glomeruli in the olfactory lobes. The high number of the 5HT-IR neurons and the extensive neuronal processes present in various regions of the synganglion suggest that serotonin plays a significant role in tick physiology. This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation by the USDA for its use. The U.S. Government’s right to retain a non-exclusive, royalty free license in and to any copyright is acknowledged.     

Phosphorylation determines two distinct species of Tau in the central nervous system

The monoclonal antibody, Tau-1, which had previously been used to localize tau to the axonal compartment in brain has been reutilized for light and electron microscopic immunohistochemistry following phosphatase treatment of tissue. We report here that a significant quantity of tau in the central nervous system is phosphorylated in situ at or near the Tau-1 epitope, preventing the binding of the Tau-1 antibody. Upon removal of this/these phosphate group(s), however, Tau-1 was observed in the somatodendritic compartment of neurons as well as in axons. Furthermore, intense staining was also observed in astrocytes and in perineuronal glial cells. This immunoreactivity was present along the lengths of microtubules and on ribosomes (polysomes). Treatment of immunoblots of extracts of whole cerebral cortex with phosphatase confirmed the immunohistochemical results in that a 50-65% increase in Tau-1 binding to the tau region of the blot was noted. Moreover, a novel monoclonal antibody, Tau-2, was also used in these experiments. This antibody binds only to tau and localizes along microtubules in axons, somata, dendrites, and astrocytes and on ribosomes (polysomes) without phosphatase pretreatment.     

Dynamics of changes in the light absorption by snail central nervous system ganglia during excitation

It was shown that changes in the absorption of light by the left parietal ganglion of the snail upon electric stimulation of the cerebral ganglion are dependent on the concentration of colchicine 10(-4), 10(-3), 10(-2) M in saline.     

Emergence in the central nervous system

“Emergence” is an idea that has received much attention in consciousness literature, but it is difficult to find characterizations of that concept which are both specific and useful. I will precisely define and characterize a type of epistemic (“weak”) emergence and show that it is a property of some neural circuits throughout the CNS, on micro-, meso- and macroscopic levels. I will argue that possession of this property can result in profoundly altered neural dynamics on multiple levels in cortex and other systems. I will first describe emergent neural entities (ENEs) abstractly. I will then show how ENEs function specifically and concretely, and demonstrate some implications of this type of emergence for the CNS.     

Endocannabinoids in the central nervous system

The major psychoactive component of cannabis derivatives, delta9-THC, activates two G-protein coupled receptors: CB1 and CB2. Soon after the discovery of these receptors, their endogenous ligands were identified: lipid metabolites of arachidonic acid, named endocannabinoids. The two major main and most studied endocannabinoids are anandamide and 2-arachidonyl-glycerol. The CB1 receptor is massively expressed through-out the central nervous system whereas CB2 expression seems restricted to immune cells. Following endocannabinoid binding, CB1 receptors modulate second messenger cascades (inhibition of adenylate cyclase, activation of mitogen-activated protein kinases and of focal-adhesion kinases) as well as ionic conductances (inhibition of voltage-dependent calcium channels, activation of several potassium channels). Endocannabinoids transiently silence synapses by decreasing neurotransmitter release, play major parts in various forms of synaptic plasticity because of their ability to behave as retrograde messengers and activate non-cannabinoid receptors (such as vanilloid receptor type-1), illustrating the complexity of the endocannabinoid system. The diverse cellular targets of endocannabinoids are at the origin of the promising therapeutic potentials of the endocannabinoid system.     

On the interaction between the central nervous system and the peripheral motor system

The problem of the control of voluntary human movements is considered from a cybernetic point of view. The human motor system is considered to be divided into a central part and a peripheral part. The peripheral part is relatively well known and may be regarded as a set of subsystems with well known input-output relations. The interaction between the peripheral part and the central part is related to the mechanisms of the peripheral motor part. With regard to the central part two different types of control mechanisms are possible, a) an intricate functioning of the central part which generates the control signals with regard to internal and external dynamical factors, b) the central part has some degree of independence with respect to the dynamics of the peripheral mortor part. In the latter case the central part prescribes the desired movement exactly, but the final performance of the movement is also brought about by peripheral feedback mechanisms. As a functional form of the interaction between the central part and the peripheral part it might be that the control signals are encoded in a way that is related to the muscle lengths.     

Enhanced vascularization of the central nervous system in two species of mud-burrowing fish

Synopsis Histological studies have demonstrated a significantly richer vascularization of the brain and anterior spinal cord tissues in the mud-burrowing gobies Brachyamblyopus sp. and Trypauchen sp. than three fish species that occupy a variety of non-burrowing habitats. Physico-chemical data from the mud-burrowing gobies' habitat indicate anoxic conditions in the substrate. It is suggested that the enhanced development and distribution of blood capillaries throughout the central nervous system of these two goby species may be a morphological adaptation to their environment. Appropriate physiological studies are needed to clarify this contention.