Developing neural crest cells in culture: correlation of cytochrome oxidase activity with SSEA-1 and dopamine-beta-hydroxylase immunoreactivity

Neural crest metabolism: At the crossroads of development and disease

The neural crest is a migratory stem cell population that contributes to various tissues and organs during vertebrate embryonic development. These cells possess remarkable developmental plasticity and give rise to many different cell types, including chondrocytes, osteocytes, peripheral neurons, glia, melanocytes, and smooth muscle cells. Although the genetic mechanisms underlying neural crest development have been extensively studied, many facets of this process remain unexplored. One key aspect of cellular physiology that has gained prominence in the context of embryonic development is metabolic regulation. Recent discoveries in neural crest biology suggest that metabolic regulation may play a central role in the formation, migration, and differentiation of these cells. This possibility is further supported by clinical studies that have demonstrated a high prevalence of neural crest anomalies in babies with congenital metabolic disorders. Here, we examine why neural crest development is prone to metabolic disruption and discuss how carbon metabolism regulates developmental processes like epithelial-to-mesenchymal transition (EMT) and cell migration. Finally, we explore how understanding neural crest metabolism may inform upon the etiology of several congenital birth defects.

Enhanced metabolic activity coincides with survival and differentiation of cultured rat retinal ganglion cells exposed to glutamate

Neurotransmitters are prominent candidates for trans-cellular signals that influence the development of the CNS. The present study has examined the effect of glutamate on survival, differentiation and metabolic activity of cultured rat retinal ganglion cells at 3 days in vitro. Retinal cultures from neonatal Wistar rats were treated with glutamate for 48 h. The metabolic activity was markedly increased in the retinal ganglion cells exposed to 20 microM glutamate. This was accompanied by an enhanced survival of these neurons. The number of differentiated retinal ganglion cells as determined by microtubule-associated protein-2 labeling was significantly increased following exposure to low but not higher doses of glutamate. The effect of glutamate on the metabolic activity and differentiation was blocked by tetrodotoxin. The results of the present study shows that glutamate has a significant effect on survival, differentiation and metabolic activity. An increase in the metabolic activity indicates an enhancement in the electrical activity. Thus, our results are consistent with the hypothesis that glutamate is critically involved in the regulation of electrical activity in developing rat retinal ganglion cells.

Cytochrome oxidase activity in rat retinal ganglion cells during postnatal development

In this study, the metabolic activity of rat retinal ganglion cells during postnatal development has been examined in vivo using cytochrome oxidase histochemistry. The intensity of staining was measured by optical densitometry. The activity of cytochrome oxidase in retinal ganglion cells progressively increased from postnatal day 0 (P0) and reached a peak during the second week of postnatal development (P10-P14) and declined thereafter. Our data show that the increased levels of cytochrome oxidase seen in developing retinal ganglion cells occur at the same time, when neuronal maturity and synaptogenesis reach their peaks.

Neuron-specific enolase reflects metabolic activity in mesencephalic neurons of the rat

Numerous studies on the local rate of energy metabolism of various brain regions during development and following experimental manipulation have been conducted using 2-deoxyglucose uptake and cytochrome oxidase (CO) histochemistry, both considered to be reliable indicators of long-term and short-term alterations in neuronal activity, respectively. Another method which has been related to neuronal activity is neuron-specific enolase (NSE) immunohistochemistry. An isoenzyme of enolase, a key element in the glycolytic pathway, NSE is present in neurons and neural-related cells e.g. neuroendocrine cells, pituicytes, and many tumor cells, but not in glia. The distribution on adjacent tissue sections of immunoreactive NSE and histochemically determined CO were mapped in the rat mesencephalon and adrenal medulla. Both methods showed highly restricted localization of staining which coincided with few exceptions in the most reactive areas, namely the superior colliculus, medial and lateral geniculate nuclei, red nucleus, lateral mammillary nucleus, interpeduncular nucleus and substantia nigra pars lateralis and pars reticulata. Immunoreactivity of varying intensity for NSE was also observed in perikarya and in processes of numerous scattered neurons throughout the mesencephalon, including the substantia nigra pars compacta, and reticular formation. The general correspondence in staining patterns between CO and NSE in the midbrain, supports the utility of NSE as a useful index of metabolic activity in neurons.