Daily ultrastructural remodeling of clock neurons.

In about 250 clock neurons in the brain form a network that orchestrates circadian rhythmicity. Among them, eight small Lateral ventral Neurons (s-LNvs) play a critical role, synchronizing the circadian ensemble the neuropeptide Pigment-Dispersing Factor (PDF). Moreover, their neurites show daily variations in morphology, PDF levels, synaptic markers and connectivity.

Single Objective Light Sheet Microscopy allows high-resolution brain imaging of Drosophila.

imaging of dynamic sub-cellular brain structures in is key to understanding several phenomena in neuroscience. However, its implementation has been hindered by a trade-off between spatial resolution, speed, photobleaching, phototoxicity, and setup complexity required to access the specific target regions of the small brain of . Here, we present a single objective light-sheet microscope, customized for imaging of adult flies and optimized for maximum resolution.

Mating disrupts morning anticipation in Drosophila melanogaster females.

After mating, the physiology of Drosophila females undergo several important changes, some of which are reflected in their rest-activity cycles. To explore the hypothesis that mating modifies the temporal organization of locomotor activity patterns, we recorded fly activity by a video tracking method. Monitoring rest-activity patterns under light/dark (LD) cycles indicated that mated females lose their ability to anticipate the night-day transition, in stark contrast to males and virgins.

Circadian Structural Plasticity Drives Remodeling of E Cell Output.

Behavioral outputs arise as a result of highly regulated yet flexible communication among neurons. The Drosophila circadian network includes 150 neurons that dictate the temporal organization of locomotor activity; under light-dark (LD) conditions, flies display a robust bimodal pattern. The pigment-dispersing factor (PDF)-positive small ventral lateral neurons (sLNv) have been linked to the generation of the morning activity peak (the "M cells"), whereas the Cryptochrome (CRY)-positive dorsal lateral neurons (LNds) and the PDF-negative sLNv are necessary for the evening activity peak (the "E cells") [1, 2].

Communication Among Photoreceptors and the Central Clock Affects Sleep Profile.

Light is one of the most important factors regulating rhythmical behavior of . It is received by different photoreceptors and entrains the circadian clock, which controls sleep. The retina is known to be essential for light perception, as it is composed of specialized light-sensitive cells which transmit signal to deeper parts of the brain.

Coupling Neuropeptide Levels to Structural Plasticity in Drosophila Clock Neurons.

We have previously reported that pigment dispersing factor (PDF) neurons, which are essential in the control of rest-activity cycles in Drosophila, undergo circadian remodeling of their axonal projections, a phenomenon called circadian structural plasticity. Axonal arborizations display higher complexity during the day and become simpler at night, and this remodeling involves changes in the degree of connectivity. This phenomenon depends on the clock present within the ventrolateral neurons (LNvs) as well as in glia.

Heterotopic auxiliary liver transplantation with portal flow. Gradual development of the collateral circulation.

One of the causes of auxiliary liver transplantation failure is the inter-liver competition between the host liver and the graft for the hepatotrophic factors of the portal blood. We have developed an experimental model of heterotopic partial (30%) liver isotransplant using Wistar rats so as to study this competition. Splenoportography and dissection demonstrate the existence of collateral circulation.

[Immunosuppression with cyclosporin after orthoptic liver transplant in pigs].

The immunosuppressive effect of cyclosporine A (CsA) was studied in six pigs that underwent orthotopic liver transplant (OLT). The drug was administered i.v.