Differences between ranamargarin and other tachykinins in the stimulation of ion transport in frog skin.
In frog skin, tachykinins stimulate ion transport by interaction with NK1-like receptors. The structural requirements of the peptide are the presence of the C-terminal sequence Phe-X-Gly-Leu-Met-NH(2) and at least one Pro residue in the N-terminal sequence. In this paper, we demonstrate that the C-terminal amino acid must be amidated but it can be different from Met, and that the sequence cannot be longer or shorter than 11-12 amino acids. Unexpectedly, Ranamargarin (14 amino acids, no Pro residue) increased the short circuit current value by 48 +/- 0.3%. On the basis of considerable experimental evidence, we suggest that Ranamargarin interacts with a receptor different from those of other tachykinins.
Lippe
C
C
Dipartimento di Fisiologia Generale ed Ambientale, Università di Bari -Via Amendola 165/A -70126, Bari, Italy. c.lippe@biologia.uniba.it
Bellantuono
V
V
Cassano
G
G
Quaranta
A
A
Ardizzone
C
C
D000595:Amino Acid Sequence; D000818:Animals; D017136:Ion Transport; D008969:Molecular Sequence Data; D011893:Rana esculenta; D012867:Skin / Q000378:metabolism*; D015320:Tachykinins / Q000737:chemistry / Q000502:physiology*
D015320:Tachykinins; C061715:ranamargarin