Pulmonary vein-atrial junction stretch receptors and the inhibition of drinking

A chronically implanted inflatable balloon was used to produce distension of a left pulmonary vein at its junction with the left atrium in trained conscious dogs. Balloon inflation caused a fall in the amounts of water drunk in response to injection of isoproterenol, infusion of hypertonic NaCl, or overnight water deprivation. There was also a significant increase in heart rate, but arterial, central venous, and left atrial pressures were unaltered. Blockade of the left vagosympathetic nerve prevented the inhibitory action of distension of a pulmonary vein on water intake in response to injection of isoproterenol. In experiments where the balloon was left inflated for 24 h, distension also caused a fall in the spontaneous daily water intake, whereas food intake was unaffected. Despite the fall in water intake, urine flow increased so that the dog went into negative fluid balance. In conclusion, distension of a pulmonary vein at its junction with the left atrium causes reduction in both spontaneous and induced water intake, and this inhibition is not secondary to circulatory changes or fluid retention by the kidney. The action of the receptors concerned may complement the actions of the same or similar receptors on renal function whose effects have been observed previously in acute experiments in anesthetized animals and here for the first time in conscious animals.