Effects of various neuropeptide Y/peptide YY fragments on electrically-evoked contractions of the rat vas deferens.
1. The effects of various neuropeptide Y (NPY) and peptide YY (PYY) fragments on electrically-evoked twitches in the rat isolated vas deferens were studied and compared with the effects of full length NPY and PYY. The aim was to identify the shortest NPY/PYY fragments that are capable of suppressing the contractions. 2. NPY (1-36) and C-terminal fragments of NPY (from 11-36 to 22-36) suppressed the electrically-evoked twitches in a concentration-dependent manner. On the whole there seemed to be a gradual lowering of the pIC50 values with progressive shortening of the NPY fragments (except for fragments 16-36 and 22-36 that had rather high pIC50 values). NPY 23-36, 24-36 and 25-36 suppressed the twitches at high concentrations (3 microM). NPY 26-36 was without effect as were C-terminal carboxy-deaminated NPY and glycine extended NPY (NPY-Gly-Lys-Arg). 3. PYY (1-36) and C-terminal fragments of PYY (from 11-36 to 23-36) suppressed the electrically-evoked twitches in a concentration-dependent manner. PYY 1-36 was more potent than any of the fragments. There was a tendency for shorter fragments to have lower pIC50 values. PYY 24-36 and 25-36 suppressed the twitches at high concentrations (3 microM). PYY 26-36 was without effect. 4. The findings suggest that the 12 C-terminal amino acid residues of NPY and PYY are the minimum length required to activate the Y2-receptor.
Grundemar
L
L
Department of Pharmacology, University of Lund, Sweden.
Håkanson
R
R
D000595:Amino Acid Sequence; D000818:Animals; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009478:Neuropeptide Y / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology; D019894:Peptide YY; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine; D014649:Vas Deferens / Q000187:drug effects / Q000502:physiology
D009478:Neuropeptide Y; D010446:Peptide Fragments; D010455:Peptides; D019894:Peptide YY