Presence of neuropeptide Y in human circle of Willis and its possible role in cerebral vasospasm.
Neuropeptide Y (NPY) has been demonstrated in the human circle of Willis by specific radioimmunoassay. Concentrations were similar in cadaver and peroperative specimens. NPY concentrations were highest around the basilar bifurcation (2.9 +/- 1.0 pmol/g), anterior cerebral artery (2.7 +/- 0.5 pmol/g), and carotid trifurcation (2.4 +/- 0.6 pmol/g). Concentrations were lowest in the basilar artery (1.0 +/- 0.4 pmol/g). Intracarotid administration of NPY (50 pmol to 2 nmol) to rats reduced mean cerebral cortical blood flow by 40-98%. This vasoconstriction lasted for at least 2 h. These findings suggest that NPY may be involved in the cerebral vasospasm which follows subarachnoid haemorrhage and in the maintenance of normal vascular tone.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002941:Circle of Willis / Q000032:analysis*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000139:chemically induced / Q000209:etiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology; D009478:Neuropeptide Y; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y