Pre- and postjunctional actions of neuropeptide Y and related peptides.
The effects of neuropeptide Y (NPY) and related peptide fragments on blood pressure and vagal action at the heart were compared in the anaesthetized rat. A change in vagal action was taken as a measure of presynaptic activity and a change in blood pressure was taken as a measure of postsynaptic activity. NPY, NPY-(13-36), PYY-(13-36), des-Ser22-NPY-(13-36) and a stabilized 13-36 analogue of NPY (ANA NPY) all exerted pressor actions and attenuated vagal action at the heart. The maximum vagal inhibitory or presynaptic action in order of potency was NPY, ANA-NPY, PYY-(13-36) significantly greater than NPY-(13-36), des-Ser22-NPY-(13-36). The order of potency for the half time of this effect was NPY, ANA-NPY significantly longer than PYY-(13-36) and NPY-(13-36), which were significantly longer than des Ser22-NPY-(13-36). For the pressor or postsynaptic effects, NPY increased blood pressure significantly more and for a longer duration than all the 13-36 fragments, which were not demonstrably different in this respect. These results are consistent with the proposal that there are two populations of NPY receptors. The C-terminal flanking peptide of NPY (CPON) and desamido-NPY had no effect on either vagal action at the heart or on blood pressure.
School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia.
E K
EK
Potter
L
L
Mitchell
M J
MJ
McCloskey
A
A
Tseng
A E
AE
Goodman
J
J
Shine
D I
DI
McCloskey
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005768:Gastrointestinal Hormones / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D009478:Neuropeptide Y / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D019894:Peptide YY; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D013552:Swine; D013569:Synapses / Q000187:drug effects*; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology
D005768:Gastrointestinal Hormones; D009478:Neuropeptide Y; D010446:Peptide Fragments; D010455:Peptides; D019894:Peptide YY