Influence of leptin on neurotransmitter overflow from the rat brain in vitro.

The 16-kDa polypeptide hormone, leptin along with the neurotransmitters noradrenaline and serotonin (5-HT) have important physiological roles in the regulation of a number of neuroendocrine actions particularly feeding. Leptin receptor mRNA and immunoreactivity has been reported in various brain regions, while recent studies suggest that leptin is released from the human brain. This study investigated the interactions between leptinergic and neurotransmitter systems of the rat brain in vitro. Techniques were established to simultaneously monitor the release of endogenous noradrenaline and its metabolite 3,4 dihydroxyphenylglycol (DHPG), and 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) from the rat brain. The neuromodulatory action of leptin (0.2 and 3 nM) on the overflow of noradrenaline and DHPG from the medulla and hypothalamus was examined. The effect of leptin on 5-HT and 5-HIAA overflow from the hypothalamus was also investigated. Administration of 0.2 and 3 nM leptin significantly increased medullary noradrenaline overflow to 172% and 174% of basal levels, respectively. Leptin had no significant effect on hypothalamic noradrenaline overflow, while leptin perfusion induced a significant increase in 5-HIAA overflow from the hypothalamus. This study lends support to the notion of a complex interaction of the leptinergic and brain neurotransmitters involved in the control of feeding and energy metabolism.     

Kleinere Arbeiten des pflanzenphysiologischen Institutes der Wiener Universität

Ohne Zusammenfassung     

Concerning the relationship between protein synthesis and adenosine-3',5'-cyclic phosphate-stimulated steroidogenesis in isolated rat adrenal cells.

Inhibitors of protein synthesis decrease protein synthesis in isolated rat adrenal cells to a greater extent than they decrease adenosine-3',5'-cyclic phosphate (cyclic AMP)-stimulated steroidogenesis. At low concentrations of the inhibitors, varying degrees of recovery of the rate of steroidogenesis occurs with increasing time of incubation. As the concentration is increased, the time required to achieve any recovery of the rate of steroidogenesis increases and the extent of recovery decreases. The recovery also depends on the amount of cyclic AMP present. During the process of recovery the inhibition of protein synthesis continues in a linear manner. An explanation consistent with these data involves a rapidly turningover protein, the concentration of which is independent of the level of cyclic AMP present. However, the extent of transformation of this protein to an active form depends on the concentration of cyclic AMP.     

Der Kreislauf des Stoffes in der Pflanzenwelt

Ohne ZusammenfassungObiger Aufsatz, welcher in R. Fleischer's Deutsche Revue (März 1878) erschienen ist, wurde zwar für weitere Kreise geschrieben, allein er enthält nicht nur manche neue Gedanken, sondern auch neue Beobachtungen, so dass derselbe für die Leser dieser Zeitschrift ebenfalls von Interesse sein dürfte.     

Kleinere Arbeiten des pflanzenphysiologischen Institutes der Wiener Universität

Ohne ZusammenfassungDie grösseren wissenschaftlichen Untersuchungen, welche im genannten, unter der Leitung des Gefertigten stehenden Institute ausgeführt werden, kommen in den Sitzungsberichten der kais. Akademie der Wissenschaften zur Veröffentlichung. Die kleineren dort ausgeführten Arbeiten werden fortlaufend in diesen Blättern mitgetheilt werden.     

Rapd fingerprinting of diploid Lolium perenne × hexaploid Festuca arundinacea hybrid genomes

We tested the application of RAPD technology for identification of hybrid genomes originated from a maternal clone of Lolium perenne L. (2n = 2x = 14) bearing cytoplasmic male sterility, which was pollinated separately by five clones of Festuca arundinacea Schreb. cv. Barocco (2n = 6x = 42). Six classes of RAPD markers were recognized, specific to: 1) Festuca genome and inherited into F1 hybrid genomes, 2) Lolium genome inherited into F1 hybrid genomes, 3) Lolium-specific bands not found in F1 progeny, 4) Festuca-specific bands not found in F1 progeny, 5) new bands found only in F1 hybrid profiles, 6) bands common to all parental and F1 hybrid genotypes. RAPD data were shown to have full potential a) to serve as an unequivocal proof of genome recombination in perennial ryegrass × tall fescue hybrids, b) to identify hybrid genomes, c) to reveal phenetic relationships of the accessions from crossing families, d) to enhance, by fingerprinting, the selection of superior hybrid material for further breeding. RAPD data were found to be consistent with the festucoid phenotype of F1 hybrids. This revised version was published online in July 2006 with corrections to the Cover Date.