Reduced blood pressure response to carotid body chemoreceptor stimulation in spontaneously hypertensive rats

In nine 20-24-week-old spontaneously hypertensive rats (SHR) and twelve age-matched normotensive control rats (NCR) carotid body chemoreceptors were stimulated by acid saline injected into the common carotid artery. The animals were paralyzed and atropinized. The reflex blood pressure rise in NCR (27 +/- 2 mm Hg) was significantly greater than in SHR (4 +/- 2 mm Hg). We conclude that the sensitivity of the vascular-sympathetic component of the arterial chemoreflex is decreased in adult SHR.