The carotid bodies in spontaneously hypertensive (SHR) and normotensive rats--a study concerning size, location and blood supply.

Size, anatomical position and blood supply of the carotid bodies were studied by light microscopic methods in spontaneously hypertensive rats of the Okamoto-strain (SHR) and in normotensive Wistar rats (NWR) of a random-bred strain. In both groups of animals the single carotid body was usually supplied by only one glomic artery which most frequently derived from the external carotid artery, more rarely from the occipital artery and very seldom from the internal carotid artery. In general the carotid bodies were of ellipsoide shape and compact structure and as a rule closely located to the internal carotid artery. In the NWR at the origins of their glomic arteries almost regularly circular intraarterial cushions were found; in the SHR such cushions were only seen in a few cases, and if so than they were less clearly developed. In the SHR, never in the NWR, within the carotid body the lumen of some branches of the glomic arteries was narrowed by pad-like structures. When compared with the NWR the SHR showed enlarged carotid bodies and a respiratory alcalosis, suggesting that systemic hypertension leads to morphologically and functionally detectable alterations of both carotid body structure and function.