[Role of the atrial stretch receptors in the regulation of the fluids of the anesthetized dog (author's transl)]. / Papel dos receptores de distensão atriais na regulação do volume dos fluidos do cão anestesiado.

The role of the atrial stretch receptors in the regulation of the body fluids was investigated in the anesthetized dog. Two groups of 15 animals each were used. In the first group the distention was performed by the inflation with saline solution of a balloon previously introduced in the left atrium. In the second group the right atrium was distended. In the experiments with the left atrium diuresis was induced in all animals. In the right atrium only in 5 dogs the distention resulted in diuresis, in the remaining 10 animals there was, on the contrary, antidiuresis. In the experiments with diuresis, this was accompanied by a urine with a lower osmolarity than in the control period and a greater sodium excretion. Being more pronounced the hemodynamic changes in the animals in which the right atrium was distended, one could not in this experimental set-up conclude that the right atrium plays a role similar to the one of the left atrium in regulating the body fluids in the anesthetized animal.