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)

Control of myocardial oxygen tension by sympathetic coronary vasoconstriction in the dog.

The effect of sympathetic alpha-receptor coronary vasoconstriction on myocardial oxygen tension was studied in open- and closed-chest, chloralose-anesthetized dogs. Blood oxygen tension in the coronary sinus and blood flow in the circumflex coronary artery were continuously measured in a three-part experiment. With stimulation of the left stellate ganglion (15 Hz, 3 msec, 4-7 v, 90-second train) under vagotomy control conditions (part 1), heart rate, blood pressure, and coronary blood flow increased, but coronary sinus oxygen tension decreased from 19 mm Hg to 15 mm Hg. In part 2, beta-receptor blockade with propranolol (2.0 mg/kg. iv) in the same dogs blunted the positive inotropic and chronotropic effects of sympathetic stimulation; coronary alpha-receptor vasoconstriction was unmasked, and coronary sinus blood oxygen tension fell from 17 mm Hg to 11 mm Hg. Since increases in oxygen metabolism were blunted, it appeared that the decrease in coronary sinus oxygen tension was caused by alpha-receptor coronary artery vasoconstriction. This hypothesis was tested in part 3 by the addition of alpha-receptor blockade with Dibozane (3.0 mg/kg, iv). Sympathetic stimulation no longer resulted in a change in either coronary vascular resistance or coronary sinus oxygen tension. These results indicate that the fall in oxygen tension during beta-receptor blockade in part 2 was due to alpha-receptor coronary vasoconstriction. Thus, myocardial oxygen tension may be regulated by coronary sympathetic vasomotion as well as by myocardial oxygen metabolism and local vascular control mechanisms.[1]


WikiGenes - Universities