Aim: To investigate the pathophysiological role of platelet neuropeptide Y (NPY) in hypertension.
Methods: The content of NPY in plasma and platelets from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKR) were measured by radioimmunoassay.
Results: There was no difference in NPY concentration between SHR plasma and WKR plasma (2.1 +/- 1.0 vs 1.8 + 1.0 microgram.L-1), but higher amounts of NPY in SHR platelets than in WKR platelets (32 +/- 6 vs 22 +/- 9 micrograms.L-1, P < 0.05). The platelet aggregation and the release of NPY from platelets induced by thrombin and collagen were increased in SHR; ADP did not cause NPY release from platelets, although it produced severe aggregation in both SHR and WKR.
Conclusion: The content of NPY in platelets and thrombin- and collagen-induced NPY release from platelets are higher in SHR than in WKR.