The lateral and dorsal neurons of Drosophila melanogaster: new insights about their morphology and function

This chapter summarizes our present knowledge about the master clock of the fruit fly at the neuronal level. The clock is organized in distinct groups of interconnected pacemaker neurons with different functions. All of these neurons appear to communicate with one another in order to produce the species-specific activity rhythm, which is organized in morning (M) and evening (E) activity bouts. These two activity components are differentially influenced by distinct groups of pacemaker neurons reminiscent of the Pittendrigh-Daan dual oscillator model. In the original work (Grima et al. 2004; Stoleru et al. 2004), the ventrolateral (LN(v)) and dorsolateral (LN(d)) plus some dorsal groups (DN) of clock neurons have been defined as M and E cells, respectively. We further specify that the clock neurons belong to the M and E oscillators and define a more complex picture of the Drosophila brain clock.

Die feinstrukturellen Veränderungen der Venolen und Kapillaren unter dem Einfluss weiblicher Sexualhormone

The effects of estrogen alone and of a combination of estrogen and progesterone on the subcutaneous vessels were investigated. Juvenile, virginal mice of the genetically hairless type were treated weekly with a subcutaneous injection of estradiolvalenanate or of estradiolvalenanate plus progesterone respectively. After 3 weeks the animals were sacrified and regions of skin and subcutis were examined by electron microscope. Juvenile virginal mice of the same race served as control. Characteristical changes of the endothelial cytoplasm and of the basement membrane were found predominately at the postcapillary region where most of the exchange reactions between blood and tissue take place. These changes were typical for an increased phagocytosis and an increased transport action of the endothelial cells. These findings occurred in both groups, but were much more marked in the estrogen/progesterone group. The importance of these findings and their relation to clinical symptoms in man are discussed.