Effect of maternal high‐salt diet during pregnancy on blood pressure and heart rate of adult offspring: A radiotelemetry study

We have reported that giving Sprague Dawley rats a 8% NaCl diet during pregnancy produced offspring that were hypertensive (~13 mm Hg) at 5 weeks of age. In the present investigation, we sought to determine whether the increase in blood pressure was still present in 8–9 week old male offspring. Female rats were fed a high‐salt (HS, 8%) or normal salt (NS, 0.7%) diet for 1 week before mating and throughout pregnancy. After delivery, all dams were given standard chow throughout the suckling period. Pups were weaned to standard chow at 21 days. At age 7–8 weeks, radiotelemetry probes were implanted into the abdominal aorta (n=4 for both groups). One week later, mean arterial pressure (MAP) and heart rate (HR) were recorded for 30‐second intervals every 20 minutes for four days. The high‐salt diet was then given to all rats and parameters were measured for an additional 4 days. Baseline MAP averaged over the entire dark cycle for four days was not significantly different between the two groups (HS, 119.1 ± 1.3; NS, 116.5 ± 1.5 mm Hg), but HR was significantly lower in the HS rats (407 ± 2 vs 419 ± 2 bpm, p=0.035). Switching all rats to a HS diet produced a significant increase in MAP in both groups by the second day and persisted for the ensuing 2 days. HR decreased significantly in both groups on the 1 st and 2 nd days of the HS diet, but returned to baseline by the 3 rd day. These preliminary studies suggest that any hypertension imparted to offspring by feeding their mothers HS during pregnancy does not persist into adulthood. However, a long‐term decrease in HR does persist and may explain the absence of hypertension. Supported by AHA, Western States Affiliate