Calcium channel blockade with nifedipine reduces the systemic and the pulmonary vascular reactivity to adrenergic activation in hypertension

In hypertension the systemic and the pulmonary circulation show exaggerated vascular tone and responsiveness to adrenergic stimuli. In 22 hypertensive men we tested whether the regulation of the two vascular beds is improved by calcium entry blockade with nifedipine. Mental arithmetic raised epineph...

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Bibliographic Details
Published inJournal of hypertension. Supplement Vol. 4; no. 5; p. S465
Main Authors Guazzi, M D, Bartorelli, A, Loaldi, A, Moruzzi, P, Fiorentini, C
Format Journal Article
LanguageEnglish
Published England 01.12.1986
Subjects
Adult
Calcium Channel Blockers - therapeutic use
Epinephrine - antagonists & inhibitors
Humans
Hypertension - drug therapy
Hypertension - physiopathology
Male
Nifedipine - therapeutic use
Norepinephrine - antagonists & inhibitors
Pulmonary Circulation - drug effects
Vasomotor System - drug effects
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Summary:In hypertension the systemic and the pulmonary circulation show exaggerated vascular tone and responsiveness to adrenergic stimuli. In 22 hypertensive men we tested whether the regulation of the two vascular beds is improved by calcium entry blockade with nifedipine. Mental arithmetic raised epinephrine plasma concentration (by 80%), cardiac output (CO) and blood pressure in both circuits, and caused systemic vasodilatation and pulmonary vasoconstriction. After the drug the epinephrine reaction was diminished (+20%), variations in CO and systemic blood pressure were almost unchanged and pulmonary vasoconstriction was abolished. A cold pressor test increased norepinephrine plasma concentration (by 24%), systemic and pulmonary pressure and resistance and did not alter CO. The norepinephrine response to cold was enhanced (+35%) by nifedipine, while systemic and pulmonary resistance rises were importantly attenuated (from +24% to +7% and from +41% to +1%, respectively), and greatly diminished the pressure reactivity. A sympatho-adrenal modulation by calcium blockade, per se, might have restrained the vasomotion during arithmetic. The impressive attenuation of the constrictor responses to cold, which was possibly associated with a potentiated sympathetic drive, prospects that the two circuits share a vascular contractile disorder in which calcium ions are involved.
ISSN:0952-1178