Coinjections of NPY(1-36) or [Leu31,Pro34]NPY with adrenaline in the nucleus tractus solitarius of the rat counteract the vasodepressor responses to adrenaline.
The cardiovascular effects of adrenaline microinjected alone or together with neuropeptide Y (NPY) receptor agonists into the nucleus tractus solitarius (Sol) of the anaesthetized rat have been investigated in order to evaluate NPY/adrenergic receptor interactions. In the dose range 0.05-20 nmol, adrenaline microinjected unilaterally into the Sol produced significant dose-related reductions in mean arterial blood pressure and heart rate. The vasodepressor action of a close to ED50 dose of adrenaline (0.5 nmol) was significantly counteracted by a threshold dose of NPY (1-36) (1 pmol) and of the NPY Y1 receptor agonist [Leu31,Pro34]NPY (2.5 pmol) microinjected into the Sol, but not by a threshold dose of NPY(13-36)(50 fmol), a selective Y2 receptor agonist. The present study provides evidence for an antagonistic NPY Y1/adrenergic receptor interaction in the Sol of the rat, involved in cardiovascular regulation.
Yang
S N
SN
Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Fior
D R
DR
Hedlund
P B
PB
Narváez
J A
JA
Agnati
L F
LF
Fuxe
K
K
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D008845:Microinjections; D009478:Neuropeptide Y / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors; D017552:Solitary Nucleus / Q000502:physiology*
D009478:Neuropeptide Y; D010446:Peptide Fragments; D017476:Receptors, Neuropeptide Y; C062924:neuropeptide Y (13-36); C062259:neuropeptide Y, Leu(31)-Pro(34)-; D004837:Epinephrine