COMPARISON BETWEEN ARGININE-VASOPRESSIN (AVP)-LIKE PEPTIDES IN 2 ACRIDIANS, LOCUSTA-MIGRATORIA AND SCHISTOCERCA-GREGARIA

The arginine-vasopressin-like Insect Diuretic Hormone (AVP-like IDH) i s a biologically active antiparallel dimer present together with its n on active monomeric form in two cells of the Locusta migratoria sub-oe sophageal ganglion, the vasopressine-like immunoreactive (VPLI) neuron s, as well as in the haemolymph where they are released. Two AVP-like peptides are also present in another locust, Schistocerca gregaria. Al though they exhibit chromatographic properties highly similar to those of their Locusta counterparts, their structure and biology must be di fferent. Indeed, we demonstrate here 1) the absence of AVP-like peptid es in Schistocerca haemolymph, 2) differences between these peptides a nd their Locusta homologues in the binding to receptors and in their b iological activities, 3) a non-involvement of deltamethrin, an insecti cide acting on Locusta via the AVP-like IDH metabolism, on the Schisto cerca AVP-like peptides metabolism. Our results state the heterogeneit y of a neuropeptide pattern between closely related species and lead t o a discussion about structure activity relationships.