The diuretic and natriuretic responses to stimulation of left atrial receptors in dogs with different blood volumes.

The diuretic and natriuretic responses to stimulation of atrial receptors were compared in two groups of anaesthetized dogs, one group with a high blood volume and another group with a low blood volume. A diuretic response to stimulation of the atrial receptors was obtained in the two groups of animals. Both the diuretic and the natriuretic responses to stimulation of the atrial receptors were greater in the dogs with high blood volume than in the dogs with low blood volume. In a second series of experiments, a diuretic response to stimulation of the atrial receptors was demonstrated in both groups of animals following surgical denervation of the kidney. In the denervated kidney, a large increase in heart rate, associated with stimulation of the atrial receptors, significantly contributed to the diuretic response in the dogs with high blood volume but not to the response in dogs with low blood volume. In the denervated kidney, a natriuretic response was only obtained in the dogs with high blood volume in which a large increase in heart rate was associated with stimulation of the atrial receptors. The present results show that the diuretic and natriuretic responses to stimulation of atrial receptors are greater in dogs with high blood volume than in dogs with low blood volume, and that increases in heart rate, associated with stimulation of atrial receptors, significantly contribute to the diuretic and natriuretic responses in acutely denervated kidneys in the dogs with high blood volume.