SCG postnatal remodelling - hypertrophy and neuron number stability - in Spix's Yellow-toothed Cavies (Galea spixii)

Whilst a fall in neuron numbers seems a common pattern during postnatal development, several authors have nonetheless reported an increase in neuron number, which may be associated with any one of a number of possible processes encapsulating either neurogenesis or late maturation and incomplete differentiation. Recent publications have thus added further fuel to the notion that a postnatal neurogenesis may indeed exist in sympathetic ganglia. In the light of these uncertainties surrounding the effects exerted by postnatal development on the number of superior cervical ganglion (SCG) neurons, we have used state-of-the-art design-based stereology to investigate the quantitative structure of SCG at four distinct timepoints after birth, viz., 1-3 days, 1 month, 12 months and 36 months. The main effects exerted by ageing on the SCG structure were: (i) a 77% increase in ganglion volume; (ii) stability in the total number of the whole population of SCG nerve cells (no change - either increase or decrease) during post-natal development; (iii) a higher proportion of uninucleate neurons to binucleate neurons only in newborn animals; (iv) a 130% increase in the volume of uninucleate cell bodies; and (v) the presence of BrdU positive neurons in animals at all ages. At the time of writing our results support the idea that neurogenesis takes place in the SCG of preas, albeit it warrants confirmation by further markers. We also hypothesise that a portfolio of other mechanisms: cell repair, maturation, differentiation and death may be equally intertwined and implicated in the numerical stability of SCG neurons during postnatal development. (C) 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

Neural differentiation of rat aorta pericyte cells

Pericyte perivascular cells, believed to originate mesenchymal stem cells (MSC), are characterized by their capability to differentiate into various phenotypes and participate in tissue reconstruction of different organs, including the brain. We show that these cells can be induced to differentiation into neural-like phenotypes. For these studies, pericytes were obtained from aorta ex-plants of Sprague-Dawley rats and differentiated into neural cells following induction with trans retinoic acid (RA) in serum-free defined media or differentiation media containing nerve growth and brain-derived neuronal factor, B27, N2, and IBMX. When induced to differentiation with RA, cells express the pluripotency marker protein stage-specific embryonic antigen-1, neural-specific proteins beta 3-tubulin, neurofilament-200, and glial fibrillary acidic protein, suggesting that pericytes undergo differentiation, similar to that of neuroectodermal cells. Differentiated cells respond with intracellular calcium transients to membrane depolarization by KCl indicating the presence of voltage-gated ion channels and express functional N-methyl-D-aspartate receptors, characteristic for functional neurons. The study of neural differentiation of pericytes contributes to the understanding of induction of neuroectodermal differentiation as well as providing a new possible stem-cell source for cell regeneration therapy in the brain. (C) 2011 International Society for Advancement of Cytometry