Metoclopramide-Induced Vascular Hyperreactivity: A Comparative Study Between Normotensive and Hypertensive Subjects

In the present study, we have evaluated the cardiovascular responses to the cold pressor test (CPT) under intravenous metoclopramide (MTC) treatment (7.5 &mgr;g kg(minus sign1) min(minus sign1)) during a 30-min period and two additional periods, before and after MTC by using 5% glucose solution. There was a vascular hyperreactivity induced by MTC, Delta mm Hg was 21.4/24/1 mm Hg (systolic/diastolic blood pressure [BP]) during MTC versus Delta 17.2/17.9 mm Hg during 5% glucose infusion. In nine hypertensive subjects, Delta mm Hg was 36.8/25.7 during MTC versus Delta 31/24 mm Hg during 5% glucose. Bromocriptine pretreatment (7.5 mg daily for 7 days) antagonized MTC-BP increase during CPT. We conclude the following: (1) MTC induces a greater BP response during CPT which is blocked by using bromocriptine, a known DA(2) dopaminergic agonist. (2) A dopaminergic influence is present during CPT in normotensive and hypertensive subjects.