Neuropeptide and cardiovascular responses to intravenous catheterization in normotensive and hypertensive blacks and whites.

Research suggests that heightened cardiovascular and neuroendocrine (typically catecholamine) responses to stressors may lead to the development of hypertension and that there may be race differences in patterns of reactivity that are potentially pathogenic. Certain neuropeptides exert profound effects on blood pressure (BP) and heart rate (HR), yet no published studies have examined relationships between these peptides, hypertensive status, race, and reactivity. Seventeen Black and 20 White normotensive and borderline-hypertensive male 19- to 50-year-olds underwent intravenous catheterization while cardiovascular and neuropeptide responses to the stress of being catheterized were examined. Results indicate that, in response to the stressor, Black hypertensives, showed significantly lower endorphin levels compared to Black normotensives, and White hypertensives showed significantly higher levels of beta-endorphin compared to White normotensives. Groups were not significantly different in endorphin levels at recovery. Black hypertensives also showed significantly higher stressor-induced HR and systolic and diastolic BP compared to White hypertensives and normotensives. Lower levels of beta-endorphin and lower urine sodium excretion were associated with higher BP and HR.