Neuronal death in the spinal ganglia of the chick embryo and its reduction by nerve growth factor

Abstract

In the spinal ganglia of the chick embryo, two neuronal populations can be distinguished:large, early differentiating ventrolateral (VL) cells and small, late differentiating dorsomedial (DM) cells. It was found that, beginning with stage 25, the DM cells originate from a narrow band of small, immature cells at the medial border of the ganglion, extending to the dorsolateral border. We have designated this band as the inner and outer marginal zone.Neuronal death was investigated in thoracic ganglion 18 and brachial ganglion 15 by counting degenerating cells, separately for the VL and DM populations, at every stage from stage 24 (4% days) to stage 38 (12 days). In both ganglia, separate degeneration periods were found for the VL and DM populations which do not overlap. The peaks of degeneration are: stage 27 (5% days) for the VL population in ganglion 18, stage 30 (6% to 7 days) for VL in ganglion 16, and stage 35 (8% days) for DM in both ganglia.Daily injections of 6 pg of nerve growth factor, (NGF) in 6 to 12 ~1 of 0.9% sterile salt solution into the yolk sac from stage 21 (3% days) to the day of sacrifice resulted in a significant reduction of neuronal death in the VL population of ganglion 18 and in the rescue of practically all VL neurons in ganglion 15 and all DM neurons in both ganglia, which normally would have died. This is the first demonstration of an NGF effect on VL neurons.In the analysis of the multiple effects of nerve growth factor (NGF), the sympathetic ganglia have played the dominant role; the sensory ganglia which are the other target of NGF have attracted much less attention. Yet, if one entertains the notion that NGF might be the natural trophic maintenance agent for these two neuron types (i.e., that NGF is actually produced by their target organs), then one approach to the testing of this hypothesis would be to engage in in viva experiments.For this ' Dedicated to Dr. Rita Levi-Montalcini.

Expression of seven members of the ADAM family in developing chicken spinal cord

“…Two subtypes of sensory neurons in the developing chicken DRG are distinguished by their anatomical location from E6 onward: (1) a group of early differentiated large-diameter neurons located in the ventrolateral part expressing neurotrophic tyrosine receptor kinase C (TrkC), and (2) a group of late differentiated small-diameter neurons located in the dorsomedial part expressing TrkA (Hamburger et al, 1981;Avivi and Goldstein, 2003). The distinct sensory neurons project their axons into the spinal cord and generate subtype-specific sensory-motoneuron connectivity.…”

Development of anomalous rectification (Ih) and of a tetrodotoxin‐resistant sodium current in embryonic quail neurones.

“…In the chick, ciliary neurones are post-mitotic at E4-5 (Landmesser & Pilar, 1978) and cell death occurs between E7 and E12 (Landmesser & Pilar, 1974). Similarly, in sensory ganglia, neuronal production takes place between E2 and E7 (Carr & Simpson, 1978;D'Amico-Martel & Noden, 1980) and cell death between E7 and E12 (Hamburger, Brunso-Berchtold & Yip, 1981;Straznicky & Rush, 1985). Interestingly, 80 % of the sensory neurones acquired INa(TR) between E12 and E14 whereas parasympathetic neurones never expressed this current during embryonic life.…”

Pancreatic acinar AR42J cells express functional nerve growth factor receptors

“…This does suggest that NGF may not be necessary for the endocrine differentiation of these cells. However, it is known that, in other systems, NGF and the other neurotrophic factors are implicated not only in neuronal differentiation, but also in the survival of neurones and neuronal precursors (Hamburger et al 1981, Johnson et al 1980, protecting these cells from apoptotic death (ElShamy & Ernfors 1996, Ferrari 1996. Such a protective role of NGF in AR42J should now be tested.…”