Neuropeptide Y inhibits alpha-MSH release from rat hypothalamic slices through a pertussis toxin-sensitive G protein.
The arcuate nucleus of the hypothalamus contains various types of peptidergic neurons. In particular, two distinct populations of neurosecretory neurons containing neuropeptide Y (NPY)- and alpha-melanocyte-stimulating hormone (alpha-MSH)-like immunoreactivity have been identified in the arcuate nucleus. Double-labeling immunocytochemical data have recently shown that NPY-containing fibers make synaptic contacts with proopiomelanocortin (POMC) immunoreactive neurons. We have thus investigated the possible effect of NPY on the release of alpha-MSH from rat hypothalamic slices in vitro, using the perifusion technique. NPY significantly inhibited KCl-stimulated alpha-MSH release in a dose-dependent manner. The inhibitory effect of NPY was mimicked by the Y2 agonist, NPY-(13-36), while the Y1 agonist, [Leu31,Pro34]NPY, was devoid of effect. Pretreatment of hypothalamic slices with pertussis toxin (PTX) blocked the inhibitory effect of NPY, suggesting that the action of NPY on POMC neurons is mediated through a PTX-sensitive G protein. These results support the notion that NPY may play a physiological role in the regulation of alpha-MSH release from hypothalamic neurons.
Blasquez
C
C
European Institute for Peptide Research, CNRS URA 650, UA INSERM, University of Rouen, Mont-Saint-Aignan, France.
Jégou
S
S
Tranchand Bunel
D
D
Fournier
A
A
Vaudry
H
H
D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D009478:Neuropeptide Y / Q000494:pharmacology* / Q000502:physiology; D037342:Pertussis Toxin; D011189:Potassium Chloride / Q000494:pharmacology; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D000521:alpha-MSH / Q000037:antagonists & inhibitors* / Q000378:metabolism
D009478:Neuropeptide Y; D010566:Virulence Factors, Bordetella; D000521:alpha-MSH; D011189:Potassium Chloride; D011333:Pro-Opiomelanocortin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins