Early life stress results in an exaggerated pressor response to acute air jet stress in adult male, but not female rats

Abstract

Clinical studies have associated adverse childhood experiences with increased risk for cardiovascular events in adulthood, but the mechanism(s) are unknown. In animal studies, repeated separation from the mother (maternal separation, MS) during the first two weeks of life results in an exaggerated behavioral response to aversive environmental stimuli in male but not female rats. Therefore, we hypothesized that MS would influence the hypertensive response to acute stress in adulthood. Wild-type (wt) and endothelin B receptor deficient (sl/sl) rats were separated from their mothers for 3 hr/day on days 2–14 after birth (n=4–9/group). Un-separated littermates served as controls (C). At 10 weeks of age, 24 hr mean arterial pressure (MAP; telemetry) in wt rats was not different between MS and C rats. Similarly, MS had no effect on 24 hr MAP in sl/sl rats. Rats were then placed in a restraining cage and subjected to a 3 min period of air jet pulses. The total pressor response to air jet stress (area under the curve) in male rats was significantly elevated in MS compared to C groups (49±3 vs 35±5 mmHgx3min, respectively, P<0.05). In contrast, the response to air jet stress in female wt rats was similar between MS and C (43±5 vs 48±5 mmHgx3min, respectively). The exaggerated response to air jet stress was not evident in male sl/sl rats (42±10 mmHg in MS vs 44±10 mmHgx3min in C). These results are the first to demonstrate that early life stressors result in exaggerated cardiovascular responses in adulthood.