The paraganglia within the carotid bifurcation regions of young and old spontaneously hypertensive rats (SHR) after exposure to chronic hypobaric hypoxia. II. The carotid body-like organs

The following paraganglia in the carotid bifurcations regions of spontaneously hypertensive rats (SHR) were studied: Endoneural paraganglia within the external carotid nerve, the carotid sinus nerve, the glossopharyngeal nerve, and the pharyngeal branch of the vagus nerve, the so-called periadventitial type I cells, and so-called miniglomera. Number and distribution of these paraganglia vary among different individuals. After chronically hypobaric hypoxia the volume of these paraganglia was increased but their number remained unchanged. The increase of volume was dependent on the duration of hypoxia. There were no differences between young and old SHR when the hypoxia-time was the same.