The borderline hypertensive rat (BHR) as a model for environmentally-induced hypertension: a review and update

In recent years, the burgeoning disciplines of health psychology and behavioral medicine have renewed interest in the important role that environmental factors can play in the disease process. Nowhere is this concern more well-founded than in the area of cardiovascular disorders, particularly hypertension. Epidemiologists and clinicians have long suspected that stressful life events can be a sufficient trigger for the expression of hypertension in some individuals. To understand better the ways in which these variables interact in the disease process, researchers have tried, with limited success, to produce experimental hypertension in animals by exposing them to stressful environmental paradigms. Additionally, recent investigations using the borderline hypertensive rat (BHR) have demonstrated the important role genetic factors can play in mediating both the behavioral and cardiovascular responses to environmental stressors. The current paper will review these attempts and discuss recent data from experiments using a relatively new animal model that appears to be especially appropriate for the study of environmental-genetic factors in the elaboration of essential hypertension. We will also discuss potential mechanisms by which environmental stress influences arterial pressure and suggest avenues for further inquiry into the stress-disease relationship.