Influence of age on the carotid bodies of spontaneously hypertensive (SHR) and normotensive rats. I. Arterial blood supply.

In normotensive Wistar rats (NWR) of a random-bred strain and spontaneously hypertensive rats (SHR) of the OKAMOTO-AOKI-strain origin, course, and histological features of the carotid body arteries were examined. The studies were carried out in animals aging 3 d up to 70 weeks using serial sections and light microscopic methods. In both strains of animals the single carotid body was supplied by only one artery. In the NWR the glomic artery originated in nearly equal numbers from the occipital and the external carotid artery usually far distally from the carotid bifurcation. In the SHR in most cases the glomic artery arose from the external carotid artery near the carotid bifurcation and only seldom also from the occipital artery. In both strains of rats only in a few cases the carotid body artery originated from the internal carotid artery. In the normotensive animals in all age-groups at the origin of the glomic artery almost regularly intra-arterial, circular cushions were found. In contrast, in the spontaneously hypertensive rats (SHR) these cushions were often not demonstrable or flat and dumpy. In such cases the origin of the carotid body artery looked funnelled. The functional meaning of these structures as well as the influence of systemic arterial hypertension on them is briefly discussed.