Early environmental influences can attenuate the blood pressure response to acute stress in borderline hypertensive rats

The objective of this experiment was to test the hypothesis that early environmental influences could affect cardiovascular reactivity to acute stress in borderline hypertensive rats. This study utilized a cross-fostering paradigm in which borderline hypertensive rat (BHR) pups were reared by their natural spontaneously hypertensive rat (SHR) mothers, by an adoptive SHR dam, or by an adoptive Wistar-Kyoto female. Several maternal behavior measures were taken throughout weaning. Cardiovascular responses to acute stress were measured in adult BHR offspring. SHR dams spent significantly more time engaged in arched as contrasted with passive, nursing behaviors throughout the preweaning period Although strain of dam had no effect on resting blood pressure or heart rate, BHR reared by WKY darns had a greatly reduced blood pressure response to acute stress compared with BHR raised by either natural or adoptive SHR dams. These results suggest that the expression of cardiovascular characteristics in the BHR can be modified by early environmental influences and support the hypothesis that the expression of the hypertensive phenotype in the BHR is dependent upon information that is conveyed both genetically and environmentally. (C) 1997 Elsevier Science Inc.