The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Effect of thromboxane A2/endoperoxide antagonist SQ29548 on the contractile response to acetylcholine in newborn piglet cerebral arteries.

Previous studies have shown that cholinergic stimulation results in a prostanoid-dependent cerebral vasoconstriction in piglets. The present study specifically investigated the contribution of thromboxane A2 (TXA2)/prostaglandin endoperoxide and prostaglandin F2 alpha (PGF2 alpha) to the cerebral vascular response to exogenous acetylcholine (ACh). Effects of TXA2/prostaglandin endoperoxide-receptor antagonist SQ29548 on responsiveness of pial arterioles to ACh (10(-7) and 10(-4) M), PGF2 alpha (10(-7)-10(-5) M), TXA2 mimetic 9,11-methanoepoxy prostaglandin H2 (U46619, 5 and 10 ng/ml), and norepinephrine (10(-6)-10(-4) M) were studied by use of a closed cranial window in 37 anesthetized mechanically ventilated newborn piglets. Pial arteriolar diameter was measured by intravital microscopy. Topical application of exogenous PGF2 alpha and U46619 resulted in dose-dependent cerebral vasoconstriction, and the dose-response curve for each agonist was shifted to the right by the increasing concentrations of SQ29548 (10(-6)-10(-8) M). Topical application of high concentration of ACh (10(-4) M) caused a transient 34 +/- 4% decrease in pial arteriolar diameter from 98 +/- 6 to 65 +/- 5 microns (p less than 0.05). This constriction was attenuated (16 +/- 3%) in the presence of 10(-8) M SQ29548 and abolished with 10(-6) or 10(-4) M SQ29548. SQ29548 (10(-6) M) was without effect on the vasoconstrictor response to exogenous norepinephrine. Low concentration of ACh (10(-7) M) had no consistent effect on pial arterioles in the absence or presence of TXA2/prostaglandin endoperoxide-receptor blockade. The data suggest that vascular prostaglandin/endoperoxide receptors mediate cerebral vasoconstriction upon muscarinic-receptor stimulation.[1]


WikiGenes - Universities