The goal of this study was to estimate sex particularities in activity of cholinergic, adrenergic and nitrergic influence to cardiovascular system in normotensive and hypertensive (2 kidney, 1 clip) rats under rest and stress conditions.

Rats of both sexes were instrumented with catheters in artery for measuring of mean arterial pressure (MAP) and heart rate (HR) responses to acetylcholine (0.3 μg/100g), adrenaline (10 μg/100g) and Nω-nitroarginine (L-NNA, 0.25 mg/100g) injection.

We found that hypertension was attenuated in females vs. males. During stress both normotensive and hypertensive females demonstrated more favorable pattern of MAP and HR than males. The cardiovascular sensitivity to stimulate of cholinergic and adrenergic influence was higher in normotensive group vs. hypertensive state under rest and stress. Interestingly, that normotensive and hypertensive females compared with males of both groups have greater vascular reactivity to acetylcholine/adrenaline and compensatory myocardial responses in normal and, especially, stress conditions. The vascular sensitivity to nitric oxide blockade was decreased in hypertensive rats vs. normotensive animals. Impotence, that we found more pronounced MAP response to L-NNA in both healthy and hypertensive females compared with healthy and hypertensive males under rest and stress.

Thus, an enhanced cardiovascular sensitivity to autonomic and nitrergic influence in normotensive and hypertensive females compared with males of both groups may contribute to 1) higher cardiovascular adaptation to stress, 2) a lower incidence of hypertension, 3) development less severe of hypertension in female gender.