New proctolin analogues and their myotropic effects on heart of yellow mealworm Tenebrio molitor L. and foregut of locust-Schistocerca gregaria L.
We have extended our work on structure/activity relationship of neuropeptide proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH) by evaluating the effects of the following proctolin analogues: H-X1-Tyr-Leu-Pro-Thr-OH, where X1 = D-Arg (1), N-Me-Arg (2), Can (3), D-Tyr2, D-Leu3, D-Thr5]-proctolin (12). In analogues 1-9, the N-terminal Arg-residue was replaced by basic amino acid derivatives with peptides containing amino acid residues with an isosteric system on the back side chain relative to Arg (compounds 3, 5 and 6) or homo-Arg (compound 7). Analogues 1-12 were evaluated for myotropic action on in vitro heart preparation of Tenebrio molitor, whereas peptides 2, 5 and 7-12 were tested for contractile action on isolated foregut of Schistocerca gregaria. Peptides 2 and 3 retained full cardiotropic activity in Tenebrio molitor while peptides 5 and 7 preserved 40% and 15%, respectively, locust-gut contracting activity of proctolin. Peptides 11 and 12 showed antagonistic activity in Schistocerca gregaria foregut.
Kuczer
M
M
Faculty of Chemistry, University of Wrocław, Poland.
Rosiński
G
G
Issberner
J
J
Osborne
R
R
Konopińska
D
D
D000818:Animals; D004305:Dose-Response Relationship, Drug; D006110:Grasshoppers / Q000502:physiology*; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009479:Neuropeptides; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D013712:Tenebrio / Q000502:physiology*
D009479:Neuropeptides; D009842:Oligopeptides; C011536:proctolin