Immunohistological demonstration of a CRF-like material in the central nervous system of the annelid Dendrobaena.

CSF is the most recently isolated and synthetized hypothalamic releasing factor in vertebrates. The use of an antiserum raised against CRF made it possible to reveal, in an oligochaetous annelid, immunoreactive cells in the suboesophageal ganglion and in all ganglia of the ventral nerve cord. Ten cells were numbered in each ganglion and each presents a pattern which is identical from one somite to the next. It thus appears that in the case of CRF as well as other vertebrate neuropeptides, there exist immunologically related neurosecretory products in the central nervous systems of some invertebrates.