Recent experiments have provided new insights into the way in which the synthesis of nerve growth factor (NGF) is regulated. In particular, a variety of agents have been found to influence the cellular concentration of mRNANGF and NGF both in vitro and in vivo. However, no clear mechanism has been found to indicate the existence of a feedback regulation of NGF synthesis by effector tissue innervation. We have argued in this review that some form of feedback control is likely to exist between the innervation and the cells producing the factor. One such possibility, the regulation of the availability of NGF by control of its secretion, is discussed.
- feedback regulation
- neuronal control