Antagonism of the inhibitory action of neuropeptide Y (NPY) in guinea-pig trachea by the C-terminal fragment NPY (2-36).
The C-terminal fragment of neuropeptide Y (NPY), NPY(2-36) was used as a means of discriminating between two differently located NPY receptor sites in guinea-pig trachea. Both NPY and NPY(2-36) reduced the maximal relaxation elicited by vasoactive intestinal peptide (VIP). In contrast, the C-terminal fragment did not mimic the inhibitory action of NPY on the noradrenaline-(NA) evoked response. However, pretreatment of the trachea with 30 nM NPY(2-36), 5 min before generating NA and VIP concentration-response curves in the presence of NPY, abolished the inhibitory effect of NPY on NA-elicited response but did not affect the modulatory action of NPY on VIP-induced relaxation. These results suggest that the two differently located NPY receptor sites in guinea-pig trachea are of two distinct subpopulations.
Taoudi Benchekroun
M
M
Department of Pharmacology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
St-Pierre
S
S
Fournier
A
A
Cadieux
A
A
D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D017476:Receptors, Neuropeptide Y / Q000187:drug effects; D014132:Trachea / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D009478:Neuropeptide Y; D010446:Peptide Fragments; D017476:Receptors, Neuropeptide Y; C083514:neuropeptide Y (2-36); D014660:Vasoactive Intestinal Peptide; D009638:Norepinephrine