Diuretic and myotropic activities of N-terminal truncated analogs of Musca domestica kinin neuropeptide.
Musca kinin (Musdo-K; NTVVLGKKQRFHSWG-NH(2)) and N-terminal truncated analogs of 4-14 residues in length were assayed for diuretic and myotropic activity on housefly Malpighian tubules and hindgut, respectively. The pentapeptide was the minimum sequence required for biological activity, but it was > 5 orders of magnitude less potent than the intact peptide. The pharmacological profiles of the different analogs in the two assays were very similar, suggesting the same receptor is present on both tissues. Potency was little affected by the deletion of Asn(1), but was reduced > 10-fold after the removal of Thr(2). Deletion of the next 5 residues had relatively little effect, but after the second lysyl residue (Lys(8)) was removed potency fell by one to two orders of magnitude. There was a similar drop in potency after the removal of Arg(10), and at 100 microM the pentapeptide had only 20% of the diuretic activity of the intact peptide. The importance of Arg(10) was confirmed by comparing dose-response curves for Musdo-K [6-15] and Acheta kinin-V (AFSHWG-NH(2)) in the diuretic assay; the substitution of arginine by alanine produced a significant reduction in potency and some loss of activity.
Coast
Geoffrey M
GM
School of Biological and Chemical Sciences, Birkbeck College, WC1E 7HX, London, UK. g.coast@bbk.ac.uk
Zabrocki
Janusz
J
Nachman
Ronald J
RJ
D000818:Animals; D004231:Diuresis; D004305:Dose-Response Relationship, Drug; D005260:Female; D006793:Houseflies / Q000502:physiology*; D066298:In Vitro Techniques; D019476:Insect Proteins / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D007705:Kinins / Q000737:chemistry / Q000494:pharmacology*; D008317:Malpighian Tubules / Q000187:drug effects / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009479:Neuropeptides / Q000737:chemistry / Q000494:pharmacology*
D019476:Insect Proteins; D007705:Kinins; D009479:Neuropeptides