Some observatoons on the carotid bodies of the New Zealand strain of genetically hypertensive rats.

We report preliminary studies of the carotid bodies in the New Zealand strain of hypertensive rats. Female animals have a higher blood pressure than males of the same colony, but in both sexes mean arterial pressure is elevated significantly when compared to normal animals. The carotid bodies are enlarged in both the hypertensive and normotensive animals and there is no correlation between carotid body size and arterial pressure. The only structural abnormality detected in the hypertensive carotid bodies was a gross thickening of the intimal layer of the arterioles. The content of dopamine in the organs was similar in normotensives and hypertensives but the noradrenaline levels were some 50% lower in the hypotensives. These results are discussed and compared with data available for SHR animals.