Beta-adrenoceptor stimulation increases neuropeptide Y release from sympathetic nerves in intact rats.
This study was undertaken to assess in conscious normotensive rats the effects of beta-adrenoceptor stimulation on plasma neuropeptide Y (NPY) levels. Wistar rats were subjected to adrenal demedullation on the right side and were either adrenalectomized or sham-operated on the left side. Eleven days later, the conscious rats were infused i.v. for 30 min with either isoproterenol (10 ng/min) or its vehicle. Plasma NPY levels were significantly lower (23.8 +/- 2.6 pM, means +/- S.E.M., n = 12, P < 0.01) in vehicle-treated medullectomized rats than in corresponding sham-operated controls (36.7 +/- 4.1 pM, n = 12). The medullectomized rats infused with isoproterenol showed plasma NPY levels (36.7 +/- 3.3 pM, n = 11) comparable to those of sham-operated rats having received the vehicle. These data therefore demonstrate that plasma NPY levels are lower in rats without adrenal medulla and that in these animals isoproterenol increases NPY release, most likely by activating pre-synaptic beta-adrenoceptors.
Evéquoz
D
D
Division of Hypertension, University Hospital, CHUV, Lausanne, Switzerland.
Grouzmann
E
E
Nussberger
J
J
Niederberger
M
M
Brunner
H R
HR
Waeber
B
B
D000313:Adrenal Medulla / Q000502:physiology*; D000315:Adrenalectomy; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009478:Neuropeptide Y / Q000097:blood / Q000378:metabolism*; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D000318:Adrenergic beta-Agonists; D009478:Neuropeptide Y; D007545:Isoproterenol; D009638:Norepinephrine; D004837:Epinephrine