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1.
Summary The effect of pentobarbital was studied in a mixed population of nerve and glial cells dissociated from brains of 7-day chick embryos and maintained in culture. Pentobarbital-Na was added in various concentrations ranging from 5×10–5 M to 1×10–3 M. The neuronal density was monitored by counting of neurons, neuronal identity was established by staining for Nissl Bodies and acetylcholinesterase. Over a culture period of 3 weeks, it was found that the barbiturate exerts a preferential dose-dependent cytotoxic effect on neurons.The expert technical assistance of Miss A. Wolf is appreciated. This work was supported by grant 6-74-27, INSERM (Physiologie et Pathologie du Développement Nerveux).  相似文献   

2.
Use of the enkephalinase inhibitor phosphoramidon in the in vitro radiochemical assay for juvenile hormone biosynthesis enhanced allatostatin-mediated inhibition of hormone production by corpora allata of the cockroach,Diploptera punctata. Significant increases in inhibition in day 2 virgin female CA by AST 1 (at 10–7 M) and AST 4 (10–8–10–7 M) were observed in the presence of phosphoramidon (10–5M or greater). No significant increases in inhibition were seen in CA from day 6 mated females with AST 4 (10–9–10–7M) and phosphoramidon combined. Phosphoramidon alone had no effect on JH biosynthesis. Analysis of allatostatin content of the CA, as determined by ELISA, revealed that addition of phosphoramidon to the medium increased the endogenous allatostatin conten in CA of virgin and mated females. The similarity in primary structure between allatostatins and enkephalin-like peptides and their similar distribution makes it probable that phosphoramidon acts by preventing breakdown of allatostatins within the CA.  相似文献   

3.
Summary The hydrolysis of acetylcholine chloride (0.01M) by frog's rectus extracts, is inhibited by low concentrations of 3318 CT (CI-50 3.2×10–7) and high concentrations of D.F.P. (CI-50 1.3×10–5). Inversely, the hydrolysis of butyrylcholine perchlorate is inhibited by low concentrations of D.F.P. (CI-50 3×10–9) and high concentrations of 3318 CT (CI-50 3×10–4). Both are inhibited by similar concentrations of neostigmine (CI-50 1.1×10–7 and 1.5×10–7). Frog's rectus thus contains true and pseudo-cholinesterases. The inhibitions produced by D.F.P. added to the muscle itself (and not the extract) correlates well with the potentiation of the corresponding ester. Sensitization to AcCh and to BuCh appears to be specifically related to the inhibition of Ac ChE for the former ester, of XChE for the second one.  相似文献   

4.
Summary The antibiotic bacitracin (5×10–5–4×10–4 M) increases the inhibition of the contractile response caused by both enkephalin release and direct application of Met-enkephalin 5×10–7 M in the longitudinal muscle strip preparation from guinea-pig ileum. This effect is attributed to an inhibition of enkephalin degrading peptidases by bacitracin.  相似文献   

5.
Summary The incorporation of leucice-14C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10–3 M) and decreased by cyclic AMP (10–3 M). There was no effect of 5 AMP (10–3 M). The phosphodiesterase inhibiting drugs theophylline (10–3 M) and papaverine (5×10–5 g/ml) both decreased the leucine-14C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).  相似文献   

6.
Summary The activity of the membrane ATPase of 5 organs of the golden hamster was increased by 10–7–10–3 moles/l ouabain in K+-free medium. In similar experiments on rats no increase was observed.  相似文献   

7.
Summary The presence of 10–3 M ouabain or furosemide in the perfusate inhibited saliva secretion induced by either isoproterenol (10–5 M) or phenylephrine (10–5 M) from isolated rat submandibular glands and caused characteristic alterations in the electrolyte composition of saliva.  相似文献   

8.
Serotonin (5-hydroxytryptamine, 5-HT) stimulates spawning in the zebra mussel (Dressena polymorpha), a macrofouling European bivalve that has recently invaded North America. To develop methods of controlling zebra mussel spawning, two vertebrate serotonin antagonists, methiothepin and metergoline, known to bind with high affinity to snail 5-HT receptors, were tested for their ability to block 5-HT-induced spawning in zebra mussels. Methiothepin inhibited 5-HT-induced spawning at concentrations as low as 10–6 M. Metergoline (10–4 M) inhibited 5-HT-induced spawning; however, at lower concentrations (10–8 to 10–5 M), metergoline by itself significantly induced spawning in male, but not female zebra mussels. Metergoline (10–5 M)-induced male spawning was inhibited by 10–5 M methiothepin. Thus, methiothepin is the most effective inhibitor and metergoline the most powerful inducer of spawning yet tested in zebra mussels.  相似文献   

9.
Summary ATPases of the amine storing granules from bovine adrenal medulla and splenic nerves are inhibited by Tl+++ 3×10–5 and 5×10–6 M, respectively. Tl+ up to 10–3 M is ineffective. By T1+++ in concentrations of 10–4 M or more, proteins are precipitated, so that the enzyme inhibiton by these concentrations is unspecific. If T1+ is oxidized to Tl+++ in the organism, the inhibition of granular ATPase may be responsible for the alterations of the catecholamine metabolism observed in thallium intoxication.  相似文献   

10.
Summary Both fluid secretion and transepithelial potential were stimulated by cAMP. Fluid secretion was unaffected by 5-HT over the concentration range 10–8–10–4 M. The presence of ouabain in the bathing medium effected a decrease in transepithelial potential.  相似文献   

11.
Zusammenfassung Die Enzymaktivität der IES-peroxidase in Hafer-Koleoptilen wurde durch Atrazin in Konzentrationen von 10–10–10–21 M gehemmt, im Konzentrationsbereich von 10–6–10–8 M gesteigert. Atrazin förderte ferner das Wachstum von Sojabohnen-Kallusgewebe in Gegenwart von 5 mg/l Kinetin und 10–10 bis 10–18 M Atrazin im Nähragar. Diese Einwirkung von Atrazin auf den Wuchsstoffmetabolismus der Pflanzen gibt erste Anhaltspunkte, die zahlreich beobachteten Förderungen bzw. Hemmungen des Pflanzenwachstums unter dem Einfluss von Atrazin zu erklären. Die Resultate bilden weiterhin eine neue Grundlage für eine mögliche Interpretation des «Proteineffekts» der Triazine.  相似文献   

12.
Summary The migration of leucocytes from the buffy coat of chicken blood is slightly but irregulatly inhibited by cortison. If migration of leucocytes is increased by proteus lipopolysaccharide, cortison in concentrations of 10–4–10–6, and other anti-inflammatory steroids, produce a pronounced and constant inhibition of leucocytic migration.  相似文献   

13.
Summary Glossopharyngeal nerve stimulation of the bullfrog,Rana catesbiana revealed responsiveness to low levels of cantharidin (1.3×10–6M), providing a first demonstration of neural gustatory sensitivity of an animal to this defensive chemical from blister beetles, (Meloidae).Acknowledgments. Study supported in part by grant AI 02908 from NIH.  相似文献   

14.
Summary For the sensitive determination of amines their 1-dimethyl-amino-naphthalene-5-sulphonyl derivatives were separated in two-dimensional thin-layer chromatograms. 10–10–10–11 mole per amine can be detected, when the fluorescence of the DANSyl-compounds is excited by the 365 mµ Hg line.  相似文献   

15.
Zusammenfassung Die Reaktion des mit Eserin vorbehandelten musculus rectus abdominis des Frosches auf Acetylcholin liess sich durch Oxotremorin (2.0·10–5 M), Arecolin (2.0·10–5M), Aceclidin (1.0·10–4 M) und Carbachol (2.0·10–7 M) verstärken, während Atropin (1.0·10–5 M) hemmend wirkte. Perchlorationen in Konzentrationen über 2 · 10–4 M sensibilisierten den Froschmuskel erheblich und reduzierten die Grenzdosis, bei der eine Potenzierung durch Substanzen mit muskarinähnlicher Wirkung beobachtet wird. Alle beschriebenen Reaktionen liessen sich durch Gehirnextrakte verstärken, in denen zuvor Acetylcholin durch Kochen in alkalischer Lösung zerstört worden war.

This work was supported by NIH Grants No. NB 03007 and No. 5-F1-GM-22,905.  相似文献   

16.
Summary The absorption of3H-digitoxin from perfused rat small intestine was inhibited by probenecid (1.0×10–2 M), ethacrynic acid (0.5×10–3 M), and mersalyl (8.0×10–3 M) indicating that digitoxin absorption is at least partly an active process.  相似文献   

17.
Summary Nonsteroidal antiestrogens reversibly and specifically inhibited the proliferation of two estrogen receptornegative lymphoid cell lines (EL4 and Raji) in a dose-dependent manner. [3H]Thymidine incorporation of concanavalin A-stimulated primary splenocytes was also inhibited by 10–6 M clomiphene (1-[4-(2-diethylaminoethoxy)phenyl]-1,2-diphenyl-2-chloroethylene). The antiproliferative effect could be prevented by the simultaneous presence in the growth medium of 10–5 M linoleic acid or 10–5 M arachidonic acid but not by 10–6 M estradiol. Both lymphoid cell lines had high affinity antiestrogen-binding sites whose affinity could be altered by conditions of growth. Growth of EL4 cells in RPMI 1640 medium supplemented with charcoal-pretreated 5% fetal calf serum (charcoal-stripped medium) resulted in significantly higher affinity (Kd 0.54 nM±0.11 nM; n=6) than growth in medium supplemented with untreated serum (complete medium) (Kd=1.68 nM±0.48 nM; n=6) (p<0.001). This change in affinity was partly due to removal of fatty acids from the growth medium by charcoal pretreatment, since addition of 10–5 M linoleic acid or 10–5 M gamma-linolenic to charcoal-stripped medium decreased the affinity of the antiestrogen-binding protein. In contrast, growth in 10–5 M stearic acid or 10–5 M oleic acid did not significantly alter the affinity of the antiestrogen-binding protein, whereas 10–5 M palmitic acid significantly increased its affinity. The same fatty acids were also tested for their intrinsic effects on EL4 cell proliferation. Oleic, linoleic and gamma-linolenic acids were growth stimulatory while stearic and palmitic acids were not. Thus linoleic and gamma-linolenic acids whose presence in the growth medium was associated with decreased affinity of [3H]tamoxifen (1-[4-(2-dimethylaminoethoxy)phenyl]-1,2-diphenylbut-1(Z)-ene) binding to the intracellular antiestrogen-binding protein were also growth stimulatory. Unsaturated fatty acids have previously been shown to inhibit binding of [3H]tamoxifen to the antiestrogen-binding protein in a cell-free system. The present observations demonstrate that unsaturated fatty acids also modify the affinity of the antiestrogen-binding protein in intact cells.  相似文献   

18.
Summary Trypsin-treatment of human fat cells results in the potentiation of the lipolytic response and the cAMP accumulation induced by theophylline (5·10–4 M) but not of those induced by theophylline (5·10–3 M). The amount of cAMP formed after exposure to theophylline (5·10–3 M) plus norepinephrine (5·10–6 M) remains, however, 2.6fold higher in trypsin-treated human fat cells than in the control ones.Acknowledgments. The authors gratefully acknowledge the help of the surgical staff of the C. H. I. of Poissy. This work was supported by grants from the C. H. I. of Poissy and from the Université René Descartes.  相似文献   

19.
Riassunto La naringenina alla concentrazione di 10–4 M inibisce in modo totale l'emissione di gemme in radici diCichorium intybus in vitro senza tuttavia bloccare completamente la callogenesi. A concentrazioni scalari minori (10–5, 10–6, 10–7 M) questa sostanza causa una inibizione solo nella fase iniziale dell'esperienza.  相似文献   

20.
Summary The rate of p-hydroxylation of14C-(-)-amphetamine by liver microsomes was higher than that of (+)-isomer in phenobarbital-treated male rats. The apparent Km values for (-)- and (+)-amphetamine hydroxylation were 4.54×10–5 M and 2.27×10–5 M respectively, in both treated and control animals.  相似文献   

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