Blood volume and carotid body size responses in spontaneously hypertensive rats during chronic treatment with hypobaric hypoxia or almitrine bismesylate.

The influence of chronic stimulation of the peripheral arterial chemoreceptors on plasma and red cell volumes and on carotid body volume was studied in spontaneously hypertensive rats (SHR). The animals were exposed to chronic hypobaric hypoxia or a chronic treatment with almitrine bismesylate from the 17th to the 30th week of life. At the end of the experiment the plasma volume was significantly lower in chronic hypobaric and almitrine-treated animals; the red cell volume was significantly higher in chronic hypoxic SHR only. The carotid body volume was also higher only in chronic hypoxic animals. It can be concluded that long-term stimulation of the peripheral arterial chemoreceptors influences the adjustment of the plasma volume.