Cardiac Output and the Blood Pressure Increase in Deoxycorticosterone Acetate-Salt Hypertension After Nicotine Infusion

We wished to determine if nicotine exaggerates the blood pressure increase in deoxycorticosterone (DOCA)-salt hypertension. Uninephrectomized, male Sprague-Dawley rats were implanted with DOCA pellets (75 mg) and placed on a 5.2% salt diet for sixteen days and then infused with nicotine (DOCA-Nicotine; 2.4 mg/kg/day) or vehicle (DOCA-Sham). Control animals were treated with vehicle (Control) or nicotine (Control-Nicotine). The DOCA-Nicotine group had significantly greater tail-cuff blood pressures than the DOCA-Sham group by one week of nicotine infusion. At 2.5 weeks of nicotine infusion the DOCA-Nicotine rats had significantly greater tail-cuff blood pressures, direct arterial blood pressures, and cardiac outputs compared to the DOCA-Sham animals. Renal blood flows were similar in the two groups. Control-Nicotine animals demonstrated no response to nicotine during 2.5 weeks of infusion. We conclude that in the DOCA-salt rat nicotine induces an exaggerated rise in blood pressure and that the mechanism involves an increase in cardiac output.