Effect of age on blood pressure and small vessel reactivity in male rabbits

Direct blood pressure measurements were made on male rabbits from 3 to 55 months old to determine if blood pressure increases with age in this animal model as it does in humans. To assess the effects of age on vascular reactivity, strips of small ear artery and skeletal muscle artery were taken from these animals and tested with norepinephrine, potassium, histamine, and isoproterenol in vitro. Heart rate did not differ between age groups, but blood pressure was significantly higher in older age groups compared to 3-month-old-rabbits. Vessels from older animals were thicker and less sensitive to norepinephrine. Responses to potassium, histamine, and isoproterenol were not different between age groups. The results suggest that male rabbits offer a good model of age-related increases in blood pressure, and that changes in vascular adrenergic reactivity may occur with age in male rabbits.