P2 purinoceptor‐mediated control of rat cerebral (pial) microvasculature; contribution of P2X and P2Y receptors

摘要: 1 Purine and pyrimidine nucleotides evoke changes in the vascular tone of medium to large cerebral vessels through activation P2 purinoceptors. We have applied receptor drugs rat pial arterioles measured arteriole diameter (o.d. 40–84 μm at rest), recorded currents from arteriolar smooth muscle cells using patch-clamp techniques. 2 Transient vasoconstrictions rapidly inactivating were evoked by α,β-methylene ATP (0.1–30 μm) sensitive antagonists suramin iso-PPADS. 3 UTP UDP (0.1–1000 sustained suramin-sensitive vasoconstrictions. 4 ATP 2-methylthioATP (2MeSATP, 300 transient followed vasodilatations. ADP application resulted only vasodilatation (EC50∼4 μm). Vasodilator responses ATP, 2MeSATP or unaffected (100 μm). 5 RT-PCR analysis indicated that P2X1–7 P2Y1,2,6 RNA can be amplified sheet. Our results provide direct evidence for presence functional P2X receptors with a phenotype resembling P2X1 subtype on resistance arterioles. The pharmacological properties pyrimidine-evoked suggest combination P2Y2- P2Y6-like are responsible vasoconstrictions. It is therefore likely their associated involved complicated regulatory system control blood pressure.