Neuropeptide Y and [Leu31,Pro34]neuropeptide Y potentiate potassium-induced noradrenaline release in the paraventricular nucleus of the aged rat.
This microdialysis study investigated the effects of NPY and the Y1 selective agonist [Leu31, Pro34]NPY on basal and potassium-stimulated noradrenaline release in the PVN of 18-month-old anaesthetised male Sprague-Dawley rats. Microdialysate noradrenaline, DOPAC and HVA concentrations were measured by HPLC after i.c.v. administration of 2 nmol NPY, [Leu31, Pro34]NPY or vehicle. [Leu31, Pro34]NPY produced a significant 40% reduction in basal noradrenaline concentration (P < 0.05). Aged rats had blunted noradrenaline response to potassium stimulation, however stimulated noradrenaline release was similar in 18-month-old NPY-treated animals and 3-month-old saline treated age controls (2.8 and 3.2 times resting, respectively). [Leu31, Pro34]NPY induced a significantly greater release of noradrenaline in response to KC1 (5.0 times resting, P < 0.05). Thus, in 18-month-old animals with reduced endogenous hypothalamic NPY content, administration of NPY or [Leu31, Pro34]NPY increased potassium-induced noradrenaline release to levels seen in 3-month-old rats. This effect may be mediated by an NPY Y1 receptor.
Hastings
J A
JA
School of Biological and Chemical Sciences, Deakin University, Victoria, Australia.
Pavia
J M
JM
Morris
M J
MJ
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D004357:Drug Synergism; D006719:Homovanillic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D017551:Microdialysis; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D009478:Neuropeptide Y; D015102:3,4-Dihydroxyphenylacetic Acid; C062259:neuropeptide Y, Leu(31)-Pro(34)-; D011188:Potassium; D009638:Norepinephrine; D006719:Homovanillic Acid