Release of neuropeptide Y (NPY) induced by tyramine in the isolated vas deferens of rat.
The effect of tyramine on the isolated vas deferens of rats was investigated. Tyramine induced a dose-dependent contraction which was blocked by phentolamine and disappeared in adrenergic denervated tissues. In the presence of an antiserum to neuropeptide Y (NPY), the contraction induced by concentrations of tyramine greater than 10 microM was markedly increased. In addition to inducing the release of 3H-norepinephrine (NE), tyramine evoked a concentration-dependent efflux of NPY-like immunoreactivity (NPY-LI) from synaptosomal preparations. This action was not modified either by the removal of calcium ion from the medium or by the pretreatment with tetrodotoxin (0.5 microM). Desipramine suppressed the NPY-LI release induced by tyramine apparently by the inhibition of the uptake of tyramine is suggested by the significant positive correlation between the reduction of 14C-tyramine uptake and the inhibition of NPY-LI release induced by desipramine (r = 0.946). Therefore, we suggest that tyramine does induce the release of NPY from rat vas deferens, in addition to effecting NE secretion.
D000818:Animals; D003891:Desipramine / Q000494:pharmacology; D006145:Guanethidine / Q000494:pharmacology; D006892:Hydroxydopamines / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009478:Neuropeptide Y / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013563:Sympathectomy, Chemical; D013574:Synaptosomes / Q000187:drug effects; D014439:Tyramine / Q000494:pharmacology*; D014649:Vas Deferens / Q000187:drug effects
D006892:Hydroxydopamines; D009478:Neuropeptide Y; D016627:Oxidopamine; D003891:Desipramine; D009638:Norepinephrine; D014439:Tyramine; D006145:Guanethidine