A simple silver nitrate impregnation of nerve fibres with preservation of acetylcholinesterase activity at the motor end-plate

A rapid silver nitrate impregnation of nerve fibres has been devised to maintain a histochemically detectable acetylcholinesterase activity at the motor end-plates.     

Spontaneous transmitter release from motor nerve endings in muscle fibres of castrated and old animals

Zusammenfassung Die spontane Transmitterfreisetzung von Nervenendigungen wird in stark atrophischen Muskelfasern des M. levator ani alter Tiere stark erniedrigt, nach Kastration aber normal gefunden. Die Atrophie nach Kastration wird als eine Inaktivitätsatrophie interpretiert und nicht als Folge einer Verminderung der spontanen Transmitterfreilegung. Im Gegensatz dazu fÜhren denervationsanaloge Veränderungen bei der Altersatrophie zu starker Reduktion der Transmitterfreisetzung.     

Inhibition of the NADP-linked glutamate dehydrogenase fromTrypanosoma cruzi by silver nitrate

Summary The purified NADP-linked glutamate dehydrogenase fromTrypanosoma cruzi was strongly inhibited by silver nitrate. The inhibition was reversed by reduced glutathione, and was modified by the presence of the substrates during preincubation of the enzyme with the inhibitor.This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Secretaría de Estado de Ciencia y Technología de la República Argentina. JJC is a member of the Carrera del Investigador Científico, and SMJ a Research Fellow, of the former Institution.     

Endothelial nerve fibres in the cornea of the frogRana ridibunda

Summary The ultrastructural study of the frog cornea revealed the existence of intraendothelial nerve fibres. These nerve fibres are unmyelinated elements but surrounded by cytoplasmic lamellae of Schwann cells.Supported by D.C.I.N.P. Grant 78-77.     

Quantitative determination of acetylcholinesterase activity in individual megakaryocytes at various stages of maturation

Zusammenfassung Die Aktivität der Azetylcholinesterase von einzelnen Megakaryozyten verschiedener Reifegrade wurde mit Hilfe des Cartesischen Tauchers bestimmt. Die Megakaryozyten zeigen auf dem Megakaryoblasten- und Promegakaryozytenstadium grosse Unterschiede der Azetylcholinesteraseaktivität. In der letzten Phase der Reifung, wenn die Zellen einen Durchmesser von 45 µ erreichen, wird das Ferment am stärksten wirksam.     

Reversible necrosis at the end-plate region in striated muscles of the rat poisoned with cholinesterase inhibitors

Résumé Après l'injection d'un toxique anticholinesté-rasique à dose presque léthale, une nécrose focale des fibres musculaires striées du rat se développe en 24 h. 10 jours après l'injection, la régénération est presque totale. Les parties nécrotiques se trouvent dans les régions des plaques motrices. Les résultats obtenus suggèrent que l'action dépolarisante de l'acétylcholine au niveau des plaques motrices des muscles actifs, augmentée et prolongée par l'intoxication, est responsable de la nécrose.     

Inhibition of the NADP-linked glutamate dehydrogenase from Trypanosoma cruzi by silver nitrate.

The purified NADP-linked glutamate dehydrogenase from Trypanosoma cruzi was strongly inhibited by silver nitrate. The inhibition was reversed by reduced glutathione, and was modified by the presence of the substrates during preincubation of the enzyme with the inhibitor.     

Control of muscle insulin receptors by the motor nerve

Summary I¹²⁵ insulin binding and the uptake of oxygen and 2-deoxyglucose are increased in skeletal muscle after denervation, suggesting an increase in insulin receptors (IR). Sustained increases in the number of affinity of IR molecules may account for some properties of denervated muscle fibres.Supported by the Medical Research Service of the Veterans Administration.     

A simple accurate method for determining the activity of proteolytic enzymes

Riassunto Nel presente lavoro é descritta una semplice e rapida metodica, eseguita con i convenzionali metodi manometrici, per dosare l'attività proteolitica di enzimi.     

The cyclic motor activity of the ovine gut: its reset at a faster rhythm

Summary In adult sheep, the frequency of the migrating motor complexes (MMC) was increased by the duodenal administration of methysergide, but not affected by other 5-HT₁ or 5-HT₂ antagonists. This reset of the MMC pattern at a faster rhythm suggests a selective action on the enteric neuronal serotoninergic mechanism modulating the pacing of the gut cyclic motor activity.     

A simple approach to the toad's (Bufo melanostictus) nerve muscle preparation.

A simple and modified dorsal approach method has been made in the toad's (Bufo melanostictus) sciatic gastrocnemius nerve-muscle preparation. This method incurs less blood loss, time consumption, nerve damage and visceral spoil compared to conventional ventral approach method.     

Changes in brain acetylcholinesterase activity of young rats after chronic treatment with tremorine

Résumé La trémorine a été administrée chez les rats quotidiennement pendant 7 jours à des doses de 7.5, 22.5 ou 30 mg/kg. Les témoins ont montré des mouvements convulsifs proportionnels à la dose de trémorine. Quatre jours après l'arrêt du traitement, l'activité acétylcholinestérasique du cortex cérébral était augmentée. Il est proposé que ce change de l'activité acétylcholinestérasique reflète une utilisation accrue de l'acétylcholine corticale.

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Acknowledgement: This investigation was supported by a U.S. Public Health Service Grant No. NS 09199 and a Research Scientist Development Award No. K02 MH-42479 from the National Institute of Mental Health, National Institutes of Health.

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The author gratefully acknowledges the technical assistance ofSandra Roland.     

Effect of pentobarbital on the synaptosomal activity of acetylcholinesterase in Mongolian gerbils

The influence of Na pentobarbital anesthesia on the activity of specific and nonspecific cholinesterase was studied in the synaptosomal fraction of Mongolian gerbils' brains. These studies have shown that this barbiturate inhibits the specific activity of acetylcholinesterase only.     

Effect of pentobarbital on the synaptosomal activity of acetylcholinesterase in Mongolian gerbils

Summary The influence of Na pentobarbital anesthesia on the activity of specific and nonspecific cholinesterase was studied in the synaptosomal fraction of Mongolian gerbils' brains. These studies have shown that this barbiturate inhibits the specific activity of acetylcholinesterase only.     

Eyestalks control of diurnal rhythm of acetylcholinesterase activity in the crabOziotelphusa senex senex

Summary The crab (Oziotelphusa) displays a diurnal rhythm of acetylcholinesterase activity, with maximal activity around midnight, alternating with minimal activity at noon. Bilateral eyestalk ablation eliminates the diurnal rhythm of acetylcholinesterase activity.Acknowledgments. We wish to express our gratitude to CSIR, New Delhi for providing financial support to PSR. Reprint requests should be addressed to Prof. R. Ramamurthi.     

Cobalt-staining of motor nerve endings in the locust (Locusta migratoria)

Summary A method is described for axonal cobalt-staining of peripheral nerve branches. First experiments were carried out on abdominal muscles of the locust.     

Catecholamine-containing nerve fibres in the hind-gut of the crayfishAstacus astacus L. (Crustacea,decapoda)

Zusammenfassung Katecholamin enthaltende Nervenfasern im Enddarm vonAstacus astacus (L.) werden mit Hilfe vonFalcks undHillarps spezifischer Fluoreszenzmethode gezeigt. Die Fasern, die eine grüne Fluoreszenz abgeben, wurden in Nervenplexen der zirkulären und der längsgehenden Muskelschichten des Darmes beobachtet. Es wird angenommen, dass diese Fluoreszenz durch Noradrenalin zustande kommt.

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The research reported in this document has been sponsored by the Swedish Natural Science Research Council under grant No. 99-35.