Neuropeptide Y enhances the inhibitory effects of clonidine on 3H-noradrenaline release in synaptosomes isolated from the medulla oblongata of the male rat.
In studies on superfused synaptosomes from the rat medulla oblongata, the inhibitory effects of the alpha 2-adrenergic agonist clonidine (0.1 microM) on potassium (15 mM K+) induced 3H-noradrenaline (NA) release was potentiated by 20%, when neuropeptide Y was added to the system. The effect of NPY was detectable at low concentrations (1 nM) and was not dose-dependent. Neuropeptide Y alone produced no significant effects on 3H-NA release. The results may indicate the existence of a presynaptic NPY receptor on the noradrenaline and/or adrenaline nerve terminals, which may enhance the presynaptic alpha 2-adrenoreceptor function to inhibit 3H-NA release.
D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects* / Q000378:metabolism; D009478:Neuropeptide Y / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000187:drug effects
D009478:Neuropeptide Y; D003000:Clonidine; D011188:Potassium; D009638:Norepinephrine