Functions, Receptors, and Mechanisms of the FMRFamide-Related Peptides

We have surveyed the functions, receptors, and mechanisms of the FMRFamide-related peptides by focussing primarily on preparations we have studied. Even these few examples clearly illustrate the versatility of the FaRPs: acting as neurotransmitters, they can directly excite or inhibit target cells; or they can potentiate or oppose the actions of a variety of other neuroeffector molecules. In the end, there are no general characteristics that can be assigned to the effects of FMRFamide or its analogs. Rather, the results show that the FaRPs exhibit multiple actions on various tissues, reflecting the structural variation, not only of the peptides, but also of their receptors.