A compound of formula I A-B wherein A represents a region of the peptide having a sequence His1-Xaa2-Gln3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Xaa10-Ser11-Xaa12-Tyr13-Leu14-Xaa15-Xaa16-Xaa17-Xaa18-Xaa19-Xaa20-Xaa21-Phe22-Xaa23-Xaa24-Xaa25-Leu26-Xaa27-Xaa28-Xaa29; wherein B is the sequence selected from: His30-His31 or; His30-His31-NH 2. wherein -NH 2 represents C-terminal amidation of the peptide; wherein Xaa2 is Ser2, Gly2 or an α-aminoisobutyric acid residue; Xaa10 is Tyr10, Leu10 or Val10; Xaa12 is Lys12, His12 or Arg12; Xaa15 is Asp15, Asn15, Gln15, Glu15, Lys15 or His15; Xaa16 is Ser16, Glu16, Gln16 or Gly16; Xaa17 is Glu17, Glnl7, Arg17, Ser17 or Lys17; Xaal8 is Alal8, Ile18, His18 or Argl8; Xaa19 is Ala19, His19 or Val19; Xaa20 is Lys20, Arg20, His20 or Gln20; Xaa21 is Glu21, Tyr21, Leu21, His21 or Lys21; Xaa23 is Ile23, His23 or Val23; Xaa24 is Glu24 or Gln24; Xaa25 is Trp25, His25, Lys25, Tyr25 or Leu25; Xaa27 is Val27, Met27, Lys27, His27 or Leu27; Xaa28 is Lys28, His28 or Asn28; Xaa29 is Gly29, Thr29, His29 or Arg29; or a salt and/or solvate of said peptide or said compound, with the proviso that at least one of the following criteria apply: t) an α-aminoisobutyric acid residue is present at position 2 of the peptide sequence; u) Val10 is present at position 10 of the peptide sequence; v) Ser17 is present at position 17 of the peptide sequence; w) Ile18 is present at position 18 of the peptide sequence; x) His25 is present at position 25 of the peptide sequence; y) Lys25 is present at position 25 of the peptide sequence; z) Leu27 is present at position 27 of the peptide sequence; aa) Val 27 is present at position 27 of the peptide sequence. wherein A represents a region of the peptide having a sequence His1-Xaa2-Gln3-Gly4-Thr5-Phe6-Thr7-Ser8-Asp9-Xaa10-Ser11-Xaa12-Tyr13-Leu14-Xaa15-Xaa16-Xaa17-Xaa18-Xaa19-Xaa20-Xaa21-Phe22-Xaa23-Xaa24-Xaa25-Leu26-Xaa27-Xaa28-Xaa29; wherein B is the sequence selected from: His30-His31 or; His30-His31-NH 2. His30-His31 or; His30-His31-NH 2. wherein -NH 2 represents C-terminal amidation of the peptide; wherein Xaa2 is Ser2, Gly2 or an α-aminoisobutyric acid residue; Xaa10 is Tyr10, Leu10 or Val10; Xaa12 is Lys12, His12 or Arg12; Xaa15 is Asp15, Asn15, Gln15, Glu15, Lys15 or His15; Xaa16 is Ser16, Glu16, Gln16 or Gly16; Xaa17 is Glu17, Glnl7, Arg17, Ser17 or Lys17; Xaal8 is Alal8, Ile18, His18 or Argl8; Xaa19 is Ala19, His19 or Val19; Xaa20 is Lys20, Arg20, His20 or Gln20; Xaa21 is Glu21, Tyr21, Leu21, His21 or Lys21; Xaa23 is Ile23, His23 or Val23; Xaa24 is Glu24 or Gln24; Xaa25 is Trp25, His25, Lys25, Tyr25 or Leu25; Xaa27 is Val27, Met27, Lys27, His27 or Leu27; Xaa28 is Lys28, His28 or Asn28; Xaa29 is Gly29, Thr29, His29 or Arg29; t) an α-aminoisobutyric acid residue is present at position 2 of the peptide sequence; u) Val10 is present at position 10 of the peptide sequence; v) Ser17 is present at position 17 of the peptide sequence; w) Ile18 is present at position 18 of the peptide sequence; x) His25 is present at position 25 of the peptide sequence; y) Lys25 is present at position 25 of the peptide sequence; z) Leu27 is present at position 27 of the peptide sequence; aa) Val 27 is present at position 27 of the peptide sequence.