Interaction of xenin with the neurotensin receptor of guinea pig enteral smooth muscles.
Xenin, a 25 amino acid peptide, interacts with the neurotensin receptor subtype 1 of intestinal muscles of the guinea pig. Replacement of the C-terminal Lys-Arg peptide bond in xenin 6 by a reduced pseudo-peptide bond augmented binding affinity to isolated jejunal and colonic muscle membranes by factors of 7.7 and 21.0 respectively; the potency to contract the jejunum and to relax the colon was increased by factors of 3.2 and 1.3. The C-terminus Trp-Ile-Leu (WIL) of xenin, in contrast to the C-terminus Tyr-Ile-Leu (YIL) of neurotensin, bound competitively to the muscle membranes. WIL blocked the contractile action of xenin in the jejunum and was synergistic with the relaxing action in the colon. The Lys-Arg motif and Trp in the C-terminus of xenin are essential structures in the action of xenin on the enteral smooth muscle receptors.
DRK-Krankenhous Neuwied, Medizinische Klinik, Rheinische Friedrich-Wilhelms Universität, Bonn, Germany. g.feurle@uni-bonn.de
Gerhard E
GE
Feurle
Jörg W
JW
Metzger
Alexandra
A
Grudinki
Gerd
G
Hamscher
D000818:Animals; D005768:Gastrointestinal Hormones / Q000378:metabolism / Q000494:pharmacology; D006168:Guinea Pigs; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009496:Neurotensin; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D018028:Receptors, Neurotensin / Q000378:metabolism*
D005768:Gastrointestinal Hormones; D010455:Peptides; D018028:Receptors, Neurotensin; C077659:xenin 25; D009496:Neurotensin