  Hormonal processes along with enzymatic processing similar to that found in
vertebrates occur in annelids. Amino acid sequence determination of annelids
precursor gene products reveals the presence of the respective peptides that
exhibit high sequence identity to their mammalian counterparts. Furthermore,
these neuropeptides exert similar physiological function in annelids than the
ones found in vertebrates. In this respect, the high conservation in course of
evolution of these molecules families reflects their importance. Nevertheless,
some specific neuropeptides to annelids or invertebrates have also been in
these animals.
