Neurons molecular markers

With this in mind, the search for molecular markers that define populations of neurons in areas important for arousal is clearly warranted. In this chapter we describe the identification of four peptidergic systems that modulate different aspects of the sleep-wakefulness cycle. The success of this strategy demonstrates the need for new markers of neuronal cell types, which may define populations of neurons critical for our understanding of cortical activity and sleep. 

The EST has continued to be a popular test subject to further optimization, especially through the addition of alternative pathways of differentiation and the addition of molecular markers of effects. Besides cardiac muscle differentiation, other cell types such as neurons (29-31), osteoblasts (32), adipocytes (33), and hepato-cytes (34) have been generated in dedicated differentiation protocols, providing additional opportunities for testing the interference of differentiation pathways with chemical exposures. The addition of transcriptomics approaches to measure differential gene expression, both as influenced by the differentiation process as well as due to chemical exposure, has proven informative and may enhance the predictability of EST assays (35). The extension of this concept to human embryonic stem cell lines is still in its infancy, but has opened a new realm of options that bypasses the need for interspecies extrapolation (36). 

Though it is now accepted that neurogenesis occurs in the adult brain and that NSCs reside in the adult CNS, questions and controversy remain What is the origin of newly generated neuronal cells in the adult brain What are their molecular markers What are the factors and mechanisms controlling NSC growth and fate specification What is the potential of adult-derived stem cells What are the functions of newly generated neuronal cells in the adult brain How can we use adult NSCs therapeutically ... 

The tumors are positive for synaptophysin, chromogranin, and neuron-specific enolase and may express a variety of hormones (growth hormone, prolactin, TSH, ACTH, and FSH). A few are hormone negative and are designated as null-cell adenomas. Almost all are positive for CAM 5.2, either focally or diffusely, and about half are positive for AE 1/3. They are negative for cytokeratin 7, 19, and 20, as well as S-100 protein. Pituitary transcription factor-1 is selectively expressed in tumors that express growth hormone, prolactin, and TSH. No diagnostic molecular markers are currently in use for sporadic pituitary lesions. ... 

Combined neurotracing and immunolabeling can also be applied for electron microscopic analysis. We usually visualize BDA-labeled CFs with immunoperoxidase and DAB, and molecular markers with pre-embedding silver-enhanced immunogold. With this technique, CFs of different neuronal origins are differentially... 

Figure 4. DDC (A), serotonin (B), and tyrosine hydroxylase (C) immunore-activity in the posterior region of a wild-type Drosophila ventral ganglion. Tyrosine hydroxylase (TH) encodes the rate-limiting step in dopamine biosynthesis and is a marker for dopamine cells. B and C are the same CNS assayed for both serotonin and TH. M, medial dopamine neurons VL, ventrolateral serotonin neurons DL, dorsolateral dopamine neurons. Short unmarked arrows in C show vacuolated cells that do not contain DDC immunoreactivity. The immunoreactivity in these cells may represent a nonspecific cross-reactivity of the rat TH antibody. The length bar in A is 50 pM. The images are confocal projections generated on a Molecular Dynamics-2000 confocal laser scanning microscope.

Peripheral tissue markers include high-molecular-weight complex biomolecules (receptors) and enzyme systems that can be obtained from outside the CNS (e.g., in platelets, lymphocytes, skin fibroblasts, and erythrocytes) and are thought to reflect or parallel central neuronal activity. 

Intense investigations on the cellular and molecular chemical neuroanatomy of the NAc, as well as on its connections, neuropharmacology and electrophysiology, have identified two main sub territories, namely the shell and the core (initially identified by Herkenham et al., 1984 Zaborsky, 1985) a third subdivision, represented by the rostral pole, has also been recognized (see for review Kelly, 1999 Meredith, 1999 Zham, 1999, 2000). The organization in subregions has led to theories on a modular function of the NAc as a complex of neuronal ensembles (Pennartz et al., 1994). The shell and the core of the NAc have been demarcated also in primates, and calbindin is the most consistent marker for the shell across species (Haber, 1999). 

Fig. 1 Molecular neuroanatomy of the zebrafish olfactory epithelium, a The zebrafish olfactory rosette, b A section of the olfactory rosette hybridized with an olfactory marker protein (OMP) complementary RNA probe. Dark signals represent ciliated olfactory sensory neurons (OSNs) in the olfactory epithelium (OE). c Three types of olfactory sensory neurons in fish, d Distinct locations and molecular signatures of ciliated and microvillous OSNs. The ciliated OSNs locate in a...

Couto A, Alenius M, Dickson BJ (2005) Molecular, anatomical, and functional organization of the Drosophila olfactory system. Curr Biol 15 1535-1547 Crittenden JR, Skoulakis EM, Han KA, Kalderon D, Davis RL (1998) Tripartite mushroom body architecture revealed by antigenic markers. Learn Mem 5 38-51 Dahanukar A, Foster K, van der Goes van Naters WM, Carlson JR (2001) A Gr receptor is required for response to the sugar trehalose in taste neurons of Drosophila. Nat Neurosci 4 1182-1186 Dahanukar A, Lei Y-T, Kwon JY, Carlson JR (2007) Two Gr genes underlie sugar reception in Drosophila. Neuron 56 503-516... 

---