Modification of arterial baroreflexes by captopril in essential hypertension

Giuseppe Mancia, Gianfranco Parati, Guido Pomidossi, Guido Grassi, Giovanni Bertinieri, Nunzio Buccino, Alberto Ferrari, Luisa Gregorini, Lucia Rupoli, Alberto Zanchetti

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Abstract

Captopril lowers blood pressure without increasing heart rate and plasma norepinephrine, which suggests that this drug may potentiate arterial baroreflexes. In eight subjects with untreated essential hypertension, blood pressure was monitored intraarterially and the effects of baroreceptor stimulation or deactivation were assessed by measuring (1) the slopes of the relations between increase or reduction in systolic pressure (intravenous phenylephrine or nitroglycerin) and the resulting lengthening or shortening in R-R interval, and (2) the increase or decrease in mean arterial pressure induced by increasing and decreasing carotid transmural pressure (neck chamber). The measurements were made before and after a hypotensive oral dose of captopril (50 mg). Before captopril, the slopes of the R-R interval changes with increase and reduction in systolic pressure were 8 and 4 ms/mm Hg, respectively. The slopes of the mean arterial pressure changes with increase and reduction in carotid transmural pressure were 0.51 and 0.40 mm Hg, respectively. After captopril, the responses to baroreceptor stimulation were unaltered but those to baroreceptor deactivation were augmented. The presser and heart rate responses to hand-grip and cold exposure were unchanged by captopril. Administration of captopril is accompanied by a baroreflex potentiation which involves the lower portion of the stimulus-response curve of the reflex. This phenomenon (which may originate at the afferent baroreceptor fibers or centrally) may avoid a reduction in the tonic baroreflex influence during captopril-induced hypotension, thus contributing to the hemodynamic effects of the drug.

Original languageEnglish
Pages (from-to)1415-1419
Number of pages5
JournalThe American Journal of Cardiology
Volume49
Issue number6
DOIs
Publication statusPublished - Apr 21 1982

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ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Mancia, G., Parati, G., Pomidossi, G., Grassi, G., Bertinieri, G., Buccino, N., Ferrari, A., Gregorini, L., Rupoli, L., & Zanchetti, A. (1982). Modification of arterial baroreflexes by captopril in essential hypertension. The American Journal of Cardiology, 49(6), 1415-1419. https://doi.org/10.1016/0002-9149(82)90353-8