Isolation, sequence, and bioactivity of PDVDHVFLRFamide and ADVGHVFLRFamide peptides from the locust central nervous system.

The brain and the retrocerebral complex of the locust, Locusta migratoria, were examined for the presence of FMRFamide-related peptides (FaRPs) using an RIA specific for -RFamide. RP-HPLC of these extracts using both C18 and phenyl columns revealed the presence of several FaRPs eluting at different percentages of acetonitrile. The sequences of two peptides were determined. One sequence is identical to the previously described SchistoFLRFamide (PDVDHVFLRFamide), whereas a second peptide is novel and differs from SchistoFLRFamide in positions 1 and 4 (ADVGHVFLRFamide). The bioactivity of these native and synthetic FaRPs on locust oviduct contractions has been examined. Both peptides showed inhibitory activity on the locust oviduct. Truncated versions of PDVDHVFLRFamide revealed that the essential features for inhibition lay in the sequence HVFLRFamide.