Studies of the mechanisms underlying impairment of beta-adrenoceptor-mediated effects in human hypertension

B. Trimarco, M. Volpe, B. Ricciardelli, G. B. Picotti, M. D. Galva, R. Petracca, M. Condorelli

Research output: Contribution to journalArticlepeer-review

Abstract

To investigate the impairment of beta-adrenoceptor responsiveness in human hypertension, we evaluated the effect of an oral salt load (400 mEq/day of NaCl for 7 days) on plasma catecholamine concentrations and beta-adrenoceptor-mediated effects in 11 young patients with mild essential hypertension. Responses of heart rate and plasma cAMP to isoproterenol administration were used as indices of beta-adrenoceptor responsiveness. Salt loading induced a significant reduction in the dose of isoproterenol required to raise the heart rate by 25 bpm (CD25) (from 7.6 ± 1.5 to 5.3 ± 0.9 μg, p <0.05) and an increase in the slopes of the regression lines for heart rate changes and isoproterenol doses (ΔHR/IS) (from 3.3 ± 0.6 to 4.7 ± 0.7, p <0.05) and for plasma cyclic AMP (cAMP) level changes and isoproterenol doses (ΔcAMP/IS) (from 0.3 ± 0.06 to 1.4 ± 0.3, p <0.05). After salt loading there was a significant reduction in plasma catecholamine concentrations with a significant relationship between changes in upright plasma epinephrine levels and changes in CD25 (r = 0.904, p <0.01) and in the slopes for ΔHR/IS (r = 0.983, p <0.001) and ΔcAMP/IS (r = 0.922, p <0.001). These results support the hypothesis that the impairment of beta-adrenoceptor sensitivity observed in human hypertension is associated with a beta-adrenoceptor overstimulation due to chronically elevated adrenergic tone.

Original languageEnglish
Pages (from-to)584-590
Number of pages7
JournalHypertension
Volume5
Issue number4
Publication statusPublished - 1983

ASJC Scopus subject areas

  • Internal Medicine

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