Chemoreceptor stimulation interferes with regional XXXX pulmonary vasoconstriction.

@entity5728 @entity4486 @entity235 @entity26 @entity1503 @entity519 @entity358
@entity519 interferes with the diversion of blood flow away from @entity519 regions of the lung, possibly through activation of the arterial chemoreceptor reflex. The purpose of this study was to determine if selective stimulation of carotid chemoreceptors reduces the diversion of flow ( @entity519 vasoconstriction) when normal systemic @entity26 levels are present. @entity4486 anesthetized @entity235 were paralyzed and each lung was separately ventilated via a dual-lumen endobronchial tube. @entity358 (QL) and @entity1503 flows were measured with electromagnetic flow probes. Chemoreceptors were stimulated by perfusion of the carotid sinuses with @entity519 , hypercapnic blood. QL/QT averaged 46 +/- 4, 29 +/- 2, and 36 +/- 4% during bilateral O2 ventilation (control), left lung N2 ventilation, and left lung N2 plus chemoreceptor stimulation in @entity235 treated with the cyclo-oxygenase inhibitor @entity5728 . After vagotomy, QL/QT averaged 45 +/- 4, 27 +/- 3, and 28 +/- 2% during the same conditions. QL/QT decreased significantly from control (P less than 0.05) during left lung N2 alone but did not decrease during left lung N2 plus chemoreceptor stimulation in @entity235 with intact vagi. In contrast, QL/QT decreased significantly both before and during chemoreceptor stimulation in vagotomized @entity235 . The same responses were observed in @entity235 not treated with @entity5728 . These results indicate that selective stimulation of arterial chemoreceptors can interfere with regional @entity519 vasoconstriction and suggest that the vagus nerves may mediate this effect.
