Neuronal landmark

Immunofluorescence (IF) and genetic fluorescent labeling have become standard techniques to study the anatomy, fimction, and development of the Drosophila nervous system. This chapter provides an introduction into these techniques and is aimed to the novice in the field. Besides standard protocols for staining in whole mounts and vibratome sections, we give background information on usefiil antibodies and fly lines and provide guidelines on how to present IF data. We also introduce into the use of neuronal landmarks as a tool for precise and detailed anatomical descriptions. 

Studies of release of noradrenaline from sympathetic neurons provided the first convincing evidence that impulse (Ca +)-dependent release of any transmitter depended on vesicular exocytosis. Landmark studies carried out in the 1960s, using the perfused cat spleen preparation, showed that stimulation of the splenic nerve not only led to the detection of noradrenaline in the effluent perfusate but the vesicular enzyme, DpH, was also present. As mentioned above, this enzyme is found only within the noradrenaline storage vesicles and so its appearance along with noradrenaline indicated that both these factors were released from the vesicles. By contrast, there was no sign in the perfusate of any lactate dehydrogenase, an enzyme that is found only in the cell cytosol. The processes by which neuronal excitation increases transmitter release were described in Chapter 4. 

As noted, the formation of LB is a landmark process in the pathology of PD, although the exact process of the formation of these inclusion bodies remains unclear. In this context, it is worth noting that parkin immunoreactivity is present in LB of sporadic PD (Shimura et al 1999), although a recent study challenged this view (Huynh et al 2000). Thus, it is also possible that parkin is responsible for the formation of LB. If true, it may explain why LB are absent in AR-JP. According to model-2, mutation of parkin increases accumulation of abnormal proteins, and reaches early the threshold level necessary to cause death of neuronal cells. In other words, loss of parkin function accelerates the promotion step and thus AR-JP... 

Braun and Stent (1989b) found that ablation of peripheral neurons in the leech embryo has a variety of effects on axon outgrowth from central neurons. Ablation of individual peripheral neurons that form part of a chain of closely spaced peripheral neurons with which efferent axons associate, has no effect on the formation of those efferent axons. However, ablation of peripheral neurons nz 1, 2, 3 and pz8, which lie along nerve paths where putative landmark cells are spaced widely apart, results in the failure of nerve path formation (Fig. 

The stochastic resonanoe peradigm is compatible with single-neuron models or synaptic and channels properties and ap>phes to neuronal assembhes activated by sensory inputs and perceptual processes as well. In hterature, the landmark experiments including psychophysics, electrophysiology, functional MRI, human vision, hearing and tactile... 

For a precise anatomical description of neurons labeled via antibodies or by genetically encoded fluorescent markers, characteristic landmarks are needed. Landmark labeling is also essential as a reference to compute individual stainings into a standard brain. ... 

Neuronal tracts can be labeled with the mAb 1D4 (DSHB 1 55-1 75, provided by Corey Goodman) directed against Fasciclin II (FasII), a membrane-bound adhesion molecule. The FasII landmark system in the ventral nerve cord (VNC) of the larva is originally described by Landgraf et al. [50] see also [51]. In the VNC, FasII-positive tracts provide a sort of 3D grid as they run... 

---