Description:
<jats:sec><jats:label /><jats:p>There is epidemiological evidence that multiparity (multiple pregnancies) increases the long‐term risk for cardiovascular disease. We have shown that multiparous rats have an augmented pressor response to stress. This is due, at least in part, to an oxidative stress induced increase in vascular reactivity. We proposed that the augmented pressor response in the multiparous rats was also the result of a greater increase in sympathetic outflow. Age‐matched multiparous and virgin rats were implanted with telemetric devices to monitor renal sympathetic nerve activity (Telemetry Research) and blood pressure (DSI). One week later, they were exposed to 10 sec air jet. The stress‐induced increase in integrated mean amplitude of nerve activity was significantly higher in the virgin animals (Virgin: 3.2±1.6 uV to 36.5±12.2 uV; Multiparous: 0.8±0.6 uV to 8.9±6.2 uV; P<0.05). There was no difference between the groups with respect to the increase in spike frequency (Virgin: 28.2±7.8 to 36.6±10.0 spikes/sec; Multiparous: 16.6±2.8 to 28.6±1.4 spikes/sec; P>0.05). We conclude that, contrary to our hypothesis, the augmented pressor response of multiparous rats is due solely to increased vascular reactivity, not to a greater increase in sympathetic outflow. (HSFC)</jats:p></jats:sec>