Impaired amylase release from the parotid gland of rats treated with reserpine

Summary Using an automated system for the analysis of amylase, the release of this enzyme was compared in superfused parotid gland segments from control and reserpine treated rats. Stimulant-evoked amylase release was delayed and of smaller magnitude in the glands of the treated animals and a reduction of the transmembrane K⁺ gradient caused a smaller and short lasting reduction in Ach-evoked release of amylase in the glands from these animals.This work was supported by grants from the Cystic Fibrosis Research Trust (U.K.), Cystic Fibrosis Foundation (USA) and University of Missouri.     

Connecting Internal and External Representations: Spatial Transformations of Scientific Visualizations

Many scientific discoveries have depended on external diagrams or visualizations. Many scientists also report to use an internal mental representation or mental imagery to help them solve problems and reason. How do scientists connect these internal and external representations? We examined working scientists as they worked on external scientific visualizations. We coded the number and type of spatial transformations (mental operations that scientists used on internal or external representations or images) and found that there were a very large number of comparisons, either between different visualizations or between a visualization and the scientists’ internal mental representation. We found that when scientists compared visualization to visualization, the comparisons were based primarily on features. However, when scientists compared a visualization to their mental representation, they were attempting to align the two representations. We suggest that this alignment process is how scientists connect internal and external representations.     

Distribution du système glio-interstitiel chez les Mollusques: Les parties tonique et phasique du muscle adducteur postérieur chezAnodonta

Summary The structure and nervous supply of the tonic and the phasic parts of the posterior adductor muscle ofAnodonta were studied by electron microscopy. A teloglia accompanies the nerves of the tonic part, while this tissue is absent from the phasic part of the muscle. This distribution is compared to the parallel situation in marine gastropods; and it is tentatively proposed that the development of the gliointerstitial tissue in the muscle of a mollusc depends on the type of contraction of this muscles and/or the development of the extracellular spaces.

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Ce travail a été réalisé au sein de l'Equipe de Recherche associée au C.N.R.S. No. 183 et au Centre de Microscopie Electronique Appliquée à la Biologie de l'Université Claude Bernard.     

Force generation in glycerinated insect-flight muscles without ATP

Zusammenfassung Durch Zugabe und durch Auswaschen von Mg-Pyrophosphat (0,5 mM) oder Mg-Tripoly-Phosphat (1 mM) konnten (in Abwesenheit von ATP) in glyzerinextrahierten Fasern von fibrillären Insektenmuskeln (Lethocerus maximus) reversible Kontraktionszyklen und Änderungen des Dehnungswiderstandes bewirkt werden.

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Supported by Grant No. Ru 154/b of the Deutsche Forschungsgemeinschaft. The excellent technical assistance of Mrs.Helgard Jung is gratefully acknowledged.