Retinoic acid and development of the central nervous system

✍ Scribed by Malcolm Maden; Nigel Holder

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 987 KB
• Volume: 14
• Category: Article
• ISSN: 0265-9247
• DOI: 10.1002/bies.950140702

✦ Synopsis

exogenously applied RA has also been used to assess its effects on an teroposterior axial specification in the primary body axis and the central nervous system. In these systems the effects support the prediction that positional signalling molecules are likely to be utilised repeatedly in different parts of the embryo(6).

In this article we consider the evidence that the developing CNS and its derivative, the neural crest, is, indeed, another embryonic system in which R A iy involved in the patterning process. The kinds of evidence that support this contention are, firstly, the observations that RA stimulates neurite outgrowth in cell cultures and explants of neural tissue. Secondly, that both an excess and a deficiency of vitamin A has profound effects on the CNS. Thirdly, that RA itself as well as cytoplasmic proteins which specifically bind RA and nuclear receptors for RA are expressed in precise domains and neuronal cell types within the CNS. Each of these will now be considered in turn.

Summary

We consider the evidence that RAT, the vitamin A metabolite, is involved in three fundamental aspects of the development of the CNS: 1) the stimulation of axon outgrowth in particular neuronal sub-types; 2) the migration of the neural crest; and 3) the specification of rostrocaudal position in the developing CNS (forebrain, midbrain, hindbrain, spinal cord). The evidence we discuss involves RA-induction of neurites in cell cultures and explants of neural tissue; the teratological effects of RA on the embryo's nervous system; the observation that RA can be detected endogenously in the spinal cord; and the fact that the receptors and binding proteins for RA are expressed in precise domains and neuronal cell types within the nervous system.