The effect of ethnicity and sex on the cardiovascular responses to environmental stressors and contribution of prostaglandins (PGs) to these responses were investigated in young White European (WE), Black African (BA) and South Asian (SA) men and women. Mental stress elicited responses consistent with the pattern of the alerting response in WEs, BA and SA men including endothelium-dependent forearm vasodilatation, but BA and SA women showed forearm vasoconstriction and BA women showed exaggerated pressor responses. Repetition of mental stress did not induce short, or medium term habituation of alerting responses in any group, but BA women showed sensitization of pressor responses and forearm vasoconstriction indicating vulnerability to mental stress-induced hypertension. On the other hand, BA and SA men, but not women show blunted endothelium-dependent dilatation relative to WEs during reactive hyperaemia and exercise hyperaemia. Vasodilator and vasoconstrictor PGs contributed to the vascular components of the alerting response in BAs and SAs, but not WEs. Further, PGs contributed to reactive hyperaemia and exercise hyperaemia in WE men and women, but in BAs and SAs, PGs played a minimal role in women. `We propose that this endothelial dysfunction makes BA and SA women especially vulnerable to cardiovascular disease caused by mental stress
