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Physiologic response to stress is attenuated in rats with coronary ligation‐induced myocardial infarction
Author(s) -
Hunt Joseph L,
Zaretsky Dmitry V,
DiMicco Joseph A
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1375
Subject(s) - medicine , ligation , myocardial infarction , heart rate , cardiology , blood pressure , mean arterial pressure , hemodynamics , anesthesia
In patients who have sustained a large myocardial infarction (MI), sympathetic activation has been linked to increased mortality. Since acute psychological stressors are known to increase sympathetic activity, post‐MI patients may be more susceptible to the adverse effects of further sympathoexcitation caused by stress. However, the effects of the post‐MI state on responses to stress remain unclear. We examined the effects of large MIs produced by coronary artery ligation on the changes in heart rate (HR), mean arterial blood pressure (MAP), and body temperature (BT) evoked by experimental stress in rats instrumented for telemetry. Three weeks after ligation of the left anterior descending artery or sham surgery, rats were subjected to air jet stress for 10 min and monitored for an additional 60 min after release from the restraint tube. Baseline HR and BT were not different between MI (n=11) and sham (n=7) animals, but MAP was lower in rats with large MIs (>35%) than in shams (97 ± 1 v. 107 ± 3 mmHg). Compared to shams, MI rats exhibited significantly attenuated stress‐induced increases from baseline HR (105 ± 16 vs. 172 ± 11 bpm), MAP (11 ± 2 vs. 29 ± 2 mmHg), and BT (0.32 ± 0.17 vs. 0.96 ± 0.18 °C). The results demonstrate that large MIs attenuate the increase in HR, MAP, and BT evoked by experimental stress in rats. (Supported by NIH grant NS 19883 and AHA Pre‐Doctoral Fellowship 0515520Z.)