Untersuchungen über die β-adrenolytische Wirkung sowie den Einfluss auf Refraktärzeit und Kontraktilität von INPEA und MJ1999 am Meerschweinchenvorhof

Summary In isolated guinea-pig atria, the-adrenolytic isomerd(–)INPEA provoked a stronger prolongation of the refractory period (rp) than did the inactivel(+) isomer. The-adrenolytic drug MJ 1999 prolonged likewise the rp, although it caused no unspecific effect, i.e. an inhibition of contractile force. These observations lead to the conclusion that not only the unspecific local anaesthetic but also the specific-adrenolytic effect is of importance for the prolongation of rp.     

Dimethyl sulphoxide effect on division cells

Resumen Dimetil sulfóxido, potente antimetabolito, a distintas concentraciones altera significativamente la cinética de poblaciones meristemáticas radicales deAllium cepa L., produciendo un cuatro de alteraciones morfológicas y figuras mitóticas atípicas.     

Ascending noradrenaline neurons from the pons and the medulla oblongata

Zusammenfassung Nach einseitigen Läsionen im Rattenhirn an der Grenze zwischen Pons und Mesencephalon, konnte auf Grund von anterograden und retrograden neuronalen Veränderungen gezeigt werden, dass mindestens 2/3 der noradrenergenen Endigungen im Telencephalon und Diencephalon hauptsächlich zu den ungekreuzten, von Zellkörpern aus Pons und Medulla oblongata stammenden, Axonen gehören.     

Peptido-aminobenzophenones-novel latentiated benzo-1,4-diazepines

Summary It has been shown that cleavage of the N-terminal L-amino acids of a novel series of dipeptide derivatives of 2-aminobenzophenones occurs readily in vivo to give benzo-1,4-diazepines. Such compounds may serve as useful pro-drug forms of minor tranquillizers such as Valium^®.     

A carbohydrate inhibitor of cathepsin B activity associated with haptoglobin

Zusammenfassung Die Natur von Proteinase-Inhibitoren, die mit gewissen Plasmaproteinen assoziiert sind, wurde untersucht und gezeigt, dass die hemmende Wirkung des Haptoglobins, isoliert aus Tumor Ascitesflüssigkeit, auf Cathepsin B1 auf einer Kohlehydrat-Komponente des Haptoglobins beruht.

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Grants from the Anti-Cancer Society of Stockholm and the Gustaf V's Jubilee Fund are gratefully acknowledged.     

Enemy-induced dispersal in a parasitic wasp

Females of the parasitic waspAphidius uzbekistanicus, a specialist aphid primary parasitoid, react to the presence of their specialist hyperparasitoid enemyAlloxysta victrix by leaving the area. The wasps leave to increase their reproductive success, because only their offspring, but not the wasps themselves, are threatened by enemy attack. Furthermore, this dispersal is elicited through the action of volatile chemical cues produced by the hyperparasitoids. We provide evidence for 6-methyl-5-hepten-2-one being one of the volatiles eliciting dispersal. The tendency of the wasps to leave areas which are being colonized by their enemies reduces their efficiency as aphid antagonists.     

Calcium activity and post-ischemic suppression of protein synthesis

Increase in intracellular calcium concentration is a prominent feature of ischemia and has been considered a major factor in the initiation of ischemic pathology, which involves inhibition of protein synthesis. A reduction of calcium ion activity during and immediately after in vitro ischemia did not prevent inhibition of protein synthesis in hippocampae slices. When slices were overloaded with calcium by NMDA receptor activation or by the calcium ionophore A23187, no significant inhibition of protein synthesis was observed. We conclude that calcium overload plays only a limited role in ischemic inhibition of protein synthesis.     

Discharge pattern analysis suggests existence of a low-threshold calcium channel in cold receptors.

The regular periodic activity patterns of mammalian cold receptors have been quantitatively studied. Analysis of the timing of either single impulses or impulse groups demonstrated that the periodic receptor process is maintained independently of impulse generation and continues to operate under conditions when afferent impulses are not initiated. These results imply that the underlying conductances must be operational at threshold potentials related to impulse generation. In addition to temperature, the periodic process is considerably sensitive to calcium, which affects mainly the probability of impulse generation during each cycle. Reduction of external calcium and application of calcium entry blockers with relative selectivity for low-threshold calcium channels are similarly effective in modulating cold receptor activity. The data imply the existence of a low-threshold calcium conductance at the sensory terminal.