[Hemodynamic and biological effects of bromocriptine in essential hypertension].
Central dopaminergic dysfunction has been suggested as the cause of essential hypertension. Agonist dopaminergic substances (AD) possess documented anti-hypertensive properties. We studied the cardiovascular effects of a single oral dose of 10 mg of Bromocriptine (Br) in untreated subjects with essential hypertension. A number of hemodynamic and biological parameters (direct blood pressure, pulmonary arterial and capillary pressures, cardiac index, heart rate, right ventricular and left ventricular work indices, systemic arterial and pulmonary vascular resistance, plasma renin activity, prolactin, and circulating Br levels) were measured before and after ingestion of the drug (at I, 1,5, 2, 3, 4, 5, 6, 8, 10 and 12 hours). Despite great individual variability, under the experimental conditions, Br displayed a strong anti-hypertensive action. The fall in blood pressure was early (Ist our) progressive, stabilising between the 3rd and 6th hour and prolonged (12 hour). This response was independent of the basal blood pressure with basal plasma renin activity (R = 0.64; p less than 0.05) but not with the prolactin level. The left ventricular work index underwent a similar change. Systemic arterial resistance fell, but this occurred after the fall in blood pressure. There was an independent and significant fall in pulmonary arterial pressure and pulmonary vascular resistance. The prolactin level fell very quickly and remained low throughout the 12 hours. There was an excellent correlation between the direct blood pressure and prolactin level (r = 0.97; p less than 0.01). Plasma renin activity rose after the third hour to reach a maximum at the 8th hour. There was a weak correlation between the blood pressure and plasma renin activity (r = 0.65, p less than 0.05). The serum Br level varied from patient to patient but reached a maximum at 1 hour, remaining stable until the 6th hour before decreasing. There was a correlation between the plasma renin activity and prolactin levels at each dosage (r = 0.66; p less than 0.005). The hemodynamic effects of Br are similar to those of central anti-hypertensive agents. The changes in plasma renin activity are comparable to those observed in central dopaminergic dysfunction. The excellent chronological correlation between the change in blood pressure and prolactin level is compatible with the hypothesis of this type of dysfunction in essential hypertension, if the inhibition of prolactin is accepted as a central dopaminergic effect of bromocriptine.
D000328:Adult; D001971:Bromocriptine / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000097:blood
D001971:Bromocriptine; D011388:Prolactin
Effets hémodynamiques et biologiques de la bromocriptine dans l'hypertension artérielle essentielle.