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1.
Hisako Ikeda Jonathan Robbins 《Documenta ophthalmologica. Advances in ophthalmology》1988,69(2):175-186
Anatomical and physiological segregation of neurons into ON (brightening detector) and OFF (darkening detector) channels in the retina and subsequent visual system ensure the high sensitivity required for contrast detection and spatial discrimination. This segregation is finest at the visual axis. Neurochemically, ON and OFF ganglion cells at the visual axis seem to be distinguished by different inhibitory transmitters but not excitatory transmitters. Microiontophoretic studies of inhibitory transmitters on the retinal ganglion cells in kittens and adult cats suggest that this neurochemical distinction is poor in immature ganglion cells at the visual axis. Initially both ON and OFF cells seem to be supplied by GABAergic, glycinergic, and catecholaminergic amacrine cells, but in adults, ON cells remain supplied only by GABAergic amacrines, while OFF cells are supplied by glycinergic amacrines. Postnatal elimination of multiple inputs and strengthening of the appropriate inputs, as seen in the central nervous system, also seem to occur at the retinal neurotransmitter synapses during development. 相似文献
2.
K. H. McAllister 《Psychopharmacology》1994,116(3):317-325
D-Cycloserine (DCS) has been reported to affect the central nervous system in man. To investigate whether the compound produces specific behavioural effects, DCS was administered to male mice in a resident-intruder situation and the behaviour of the interacting mice assessed using ethological analysis. Resident mice given DCS (32.0–320.0 mg/kg PO, 60 min before testing) showed dose-dependent increases in social investigation, smaller increases in sexual behaviour and decreased aggressiveness. Defensive and flight behaviour were not affected. Intruder mice showed slight increases in sexual behaviour that were not dose-dependent, and small increases in social investigation. The increases in social investigation induced by DCS (320.0 mg/kg) in resident mice were not reversible with R-HA 966 (32.0 mg/kg IP, 30 min before testing), a blocker of the strychnine-insensitive glycine modulatory site associated with theN-methyl-D-aspartate receptor, but were blocked by the GABA antagonist bicuculline (0.56 mg/kg IP, 5 min before testing). The small DCS-induced increase in sexual behaviour in residents was reversed by R-HA 966. Within the parameters of the resident-intruder situation, DCS exerts socio-sexual behaviour-enhancing effects which are dependent upon the role of the interactant, and which are mediated by an action upon multiple substrates. DCS may be regarded as another example of a sociotropic (approach-promoting) agent.Some of these results have been presented at the 1st International Congress on Hormones, Brain and Neuropsychopharmacology, Rodos, Greece, September 12–17, 1993 相似文献
3.
The axon terminals of cone horizontal cells in the goldfish retina form typical chemical synaptic contacts in the middle of the inner nuclear layer. Approximately 60% of the identified postsynaptic elements were perikarya, axons and dendrites of bipolar cells. The other identified postsynaptic elements were perikarya and processes of interplexiform cells. We propose that the horizontal cell axon terminal contribute to the antagonistic surround responses of the bipolar cells and that they modulate inputs to the outer plexiform layer conveyed by interplexiform cells. Output synapses from horizontal cell axons to unidentified neuronal processes as well as occasional input synapses to the axons from interplexiform cell processes and unidentified perikarya were also observed in the same region of the inner nuclear layer. 相似文献
4.
孙希诰 《南方医科大学学报》1990,(4)
侧脑室注射甘氨酸使健康家兔和烧伤家兔血浆皮质酮浓度降低;注射L—谷氨酸和L—天冬氨酸使健康家兔血浆皮质酮浓度升高,但不能使烧伤后升高的血浆皮质酮浓度发生改变。提示这三种氨基酸作为神经递质参与下丘脑—垂体—肾上腺皮质轴的调控。烧伤刺激通过下丘脑引起内分泌紊乱,这种紊乱与L—谷氨酸和L—天冬氨酸失控有关。 相似文献
5.
Paolo Calabresi Emesto Fedele Antonio Pisani Giovanni Fontana Nicola B. Mercuri Giorgio Bernardi Maurizio Raiteri 《The European journal of neuroscience》1995,7(9):1889-1894
Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release. 相似文献
6.
John E. Geltosky Richard S. Smith Alice Whalley Gary Rhodes 《Journal of clinical laboratory analysis》1987,1(2):153-162
A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma. 相似文献
7.
J. L. Beal M. Freysz G. Berthelon P. D’Athis S. Briet M. Wilkening 《Journal canadien d'anesthésie》1989,36(3):278-282
This prospective and randomized study compared the consequences of two irrigating fluids, distilled water and glycine for
transurethral prostatectomy. Forty-nine consecutive unselected patients undergoing transurethral resection of the prostate
with spinal anaesthesia were investigated. The irrigating fluid was either distilled water (group A, 24 patients) or glycine
1.5 per cent (group B, 25 patients). The absorption of irrigating fluid was measured, all surgical events and any clinical
signs of TURP syndrome during and after surgery were recorded. Early signs of TURP syndrome were observed in one patient in
group A and in four in group B without further consequence. From all the biological variables, only plasma protein concentration,
haematocrit, free plasma haemoglobin and free bilirubin concentrations were found to have changed. Plasma protein concentration
and haematocrit decreased significantly during and after surgery in the two groups. Free plasma haemoglobin increased significantly
with time: a significantly higher concentration was observed in group A than group B. Free bilirubin concentration increased
with time in the two groups and was statistically greater in group A. With the two irrigating fluids, we observed a significant
amount of haemolysis and haemodilution without clinical consequences. A low irrigating fluid pressure, a short resection time,
and the use of spinal anaesthesia seems to us to be essential. Close observation of patients following transurethral prostatectomy
is needed but the choice of the irrigating fluid does not seem to be important.
Cette étude prospective et randomisée a comparé les conséquences de deux liquides d’irrigation, l’eau distillée et le glycocolle
au cours de la chirurgie prostatique par voie basse. Quarante-neuf patients consécutifs, non sélectionnés, bénéficiant d’une
résection transuréthrale de prostate sous rachianesthésie, sont étudiés. Le liquide d’irrigation est soil l’eau distillée
(groupe A, 24 patients), soit le glycocolle à 1.5 pour cent (groupe B, 25 patients). L’absorption des liquides d’irrigation,
les incidents chirurgicaux et les signes cliniques du syndrome de réabsorption sont systématiquement notés. Des signes caractéristiques
du syndrome de réabsorption sont observés dans un cas dans le groupe A et dans quatre cos dans le groupe B sans conséquence
ultérieure. Seuls la protidémie, l’hématocrite, l’hémoglobine plasmatique libre et la bilirubine libre changent significativement.
L’hémoglobine plasmatique libre augmente significativement dans les deux groupes, avec un taux plasmatique significativement
plus élevé dans le groupe A. Avec les deux liquides d’irrigation, on observe une hémolyse et une hémodilution sans conséquence
clinique. Un temps de résection court, un faible niveau de pression d’irrigation, l’utilisation de l’anesthésie rachidienne
nous semblent trés importants. Une surveillance clinique et biologique attentive pendant et après la résection transuréthrale
de prostate sont nécessaires; en revanche, le choix du liquide d’irrigation ne semble pas l’élément essentiel. 相似文献
8.
G. N. Kryzhanovskii V. N. Grafova E. I. Danilova 《Bulletin of experimental biology and medicine》1977,83(5):607-611
With the aid of tetanus toxin, which disturbs various types of inhibition, generators of excitation were created in the left and right anterior horns of the lumbar spinal cord in rats. The regimes of activity of the generators differed: the left-sided generator, formed during the longer action of the toxin, in response to activation by trigger stimulation first produced tonic, and then intermittent activity, or individual spontaneous discharges, whereas the righ-sided generator produced only tonic activity. If one generator was blocked by glycine, the other continued to operate as before. Activation of one generator led to concomitant depression of the effects of the other. During separate activation of each generator, all the spinal and supraspinal motoneuron pools synchronously reproduced the character of activity of the generator functioning at that particular moment. The generator thus played the role of a determinant structure, determining the behavior of the system. The results are examined from the standpoint of the general concept of the role of determinant structures in the activity of the nervous system and the theory of generator mechanisms of neuropathological syndromes characterized by hyperactivity of systems.Laboratory of General Pathology of the Nervous System, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 515–519, May, 1977. 相似文献
9.
目的 合成 4 -羟基 - 3,5 -二甲氧基苯甲酰甘氨酸。方法 以丁香酸为起始原料 ,经乙氧羰基化、酰氯化、酰胺化、水解四步反应制得。结果 经波谱数据及元素分析认为合成的产物为目标产物。结论 所得化合物作为 N- (4 -羟基 - 3,5 -二甲氧基苯甲酰基 ) -甘氨酰正丁基胍的中间体 ,实验还需进一步探讨改进 相似文献
10.