High dietary NaCl early in development enhances mean arterial pressure of adult rats

We investigated the long-term influence of early dietary NaCl on adult mean arterial pressure (MAP) and heart rate (HR), assessed continuously for 7 w eeks when fed water and chow containing 1% NaCl (weeks 1, 4, 7), 0% NaCl (w eeks 2-3), and 3% NaCl (weeks 5-6) while on a 12:12 light/dark cycle. Subje cts were offspring of female Sprague-Dawley rats fed solid chow consisting of either 0.1% (basal), 1% (intermediate), or 3% (high) NaCl throughout pre gnancy and lactation. After weaning on postnatal day (PD) 21, offspring wer e fed the same NaCl diet of their mother until PD 30, at which time all off spring were given Purina 5001 diet (1% NaCl) as their solid chow. On PD 60, 22 adult male offspring (eight basals, six intermediates, eight highs) wer e implanted with an aortic electronic sensor for transmitting blood-pressur e signals by telemetry. MAP and HR varied significantly across the 7-week t esting period in association with dietary NaCl levels. The three perinatal salt groups had similar HR levels on normal 1% NaCl chow. However, HR incre ased in all groups during 0% NaCl and decreased in all groups during 3% NaC l. In contrast, the average MAP levels were significantly greater in the hi ghs compared to both the intermediate and basal groups during both dark and light periods. MAP increased in high and basal groups during both 0% and 3 %; however, the increase was more pronounced in the highs. In conclusion, e xposure to high levels of dietary NaCl early in development led to a persis tent increase in MAP in adulthood. (C) 2000 Elsevier Science Inc. All right s reserved.