K. Ukena et al., INHIBITORY PENTAPEPTIDES ISOLATED FROM THE GUT OF THE EARTHWORM, EISENIA-FOETIDA, Comparative biochemistry and physiology. Part A, Physiology, 114(3), 1996, pp. 245-249
The isolated anterior gut (crop-gizzard) of the oligochaete annelid, E
isenia foetida, was used as a bioassay system to identify the bioactiv
e peptides that regulate rhythmic spontaneous contractions of the gut.
Three pentapeptides were purified from the extract of the gut (crop,
gizzard and intestine) of the earthworm. These peptides showed inhibit
ory actions on gut motility and were termed Eisenia inhibitory pentape
ptides (EIPPs). EIPPs had the most remarkable effect on the crop among
the various parts of the gut with a threshold concentration as low as
10(-10)-10(-9) M. From the pharmacological results, the inhibitory ac
tions of EIPPs on the gut motility seem to be different from those of
FMRFamide. The amino acid sequences of EIPPs were very similar to cert
ain molluscan and echiuroid peptides previously identified. This is th
e first isolation of annelid peptides inhibiting gut motility except f
or FMRFamide.