Mt. Benchekroun et al., ANTAGONISM OF THE INHIBITORY-ACTION OF NEUROPEPTIDE-Y (NPY) IN GUINEA-PIG TRACHEA BY THE C-TERMINAL FRAGMENT NPY (2-36), British Journal of Pharmacology, 109(4), 1993, pp. 902-904
The C-terminal fragment of neuropeptide Y (NPY), NPY(2-36) was used as
a means of discriminating between two differently located NPY recepto
r sites in guinea-pig trachea. Both NPY and NPY(2-36) reduced the maxi
mal relaxation elicited by vasoactive intestinal peptide (VIP). In con
trast, the C-terminal fragment did not mimic the inhibitory action of
NPY on the noradrenaline-(NA) evoked response. However, pretreatment o
f 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 i
nhibitory effect of NPY on NA-elicited response but did not affect the
modulatory action of NPY on VIP-induced relaxation. These results sug
gest that the two differently located NPY receptor sites in guinea-pig
trachea are of two distinct subpopulations.