This family contain neuropeptides, isolated from ganglia of the African giant snail, Achatina fulica. Each peptide has a Trp residue at both the N- and C-termini. Purified WWamide-1, -2 and -3 showed an inhibitory effect on the phasic contractions of the anterior byssus retractor muscle (ABRM) [1].

1: WWamide-1, -2 and -3: novel neuromodulatory peptides isolated from ganglia of the African giant snail, Achatina fulica. Minakata H, Ikeda T, Muneoka Y, Kobayashi M, Nomoto K; FEBS Lett 1993;323:104-108. PMID:8495720